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File: phpbb/db/tools.php

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Line 1Line 1
<?php
/**
*
* This file is part of the phpBB Forum Software package.
*
* @copyright (c) phpBB Limited <https://www.phpbb.com>
* @license GNU General Public License, version 2 (GPL-2.0)
*
* For full copyright and license information, please see
* the docs/CREDITS.txt file.
*
*/

namespace phpbb\db;

/**
* Database Tools for handling cross-db actions such as altering columns, etc.
* Currently not supported is returning SQL for creating tables.
*/
class tools
{
/**
* Current sql layer
*/
var $sql_layer = '';

/**
* @var object DB object
*/
var $db = null;

/**
* The Column types for every database we support
* @var array
*/
var $dbms_type_map = array();

/**
* Is the used MS SQL Server a SQL Server 2000?
* @var bool
*/
protected $is_sql_server_2000;

/**
* Get the column types for every database we support
*
* @return array
*/
public static function get_dbms_type_map()
{
return array(
'mysql_41' => array(
'INT:' => 'int(%d)',
'BINT' => 'bigint(20)',
'UINT' => 'mediumint(8) UNSIGNED',
'UINT:' => 'int(%d) UNSIGNED',
'TINT:' => 'tinyint(%d)',
'USINT' => 'smallint(4) UNSIGNED',
'BOOL' => 'tinyint(1) UNSIGNED',
'VCHAR' => 'varchar(255)',
'VCHAR:' => 'varchar(%d)',
'CHAR:' => 'char(%d)',
'XSTEXT' => 'text',
'XSTEXT_UNI'=> 'varchar(100)',
'STEXT' => 'text',
'STEXT_UNI' => 'varchar(255)',
'TEXT' => 'text',
'TEXT_UNI' => 'text',
'MTEXT' => 'mediumtext',
'MTEXT_UNI' => 'mediumtext',
'TIMESTAMP' => 'int(11) UNSIGNED',
'DECIMAL' => 'decimal(5,2)',
'DECIMAL:' => 'decimal(%d,2)',
'PDECIMAL' => 'decimal(6,3)',
'PDECIMAL:' => 'decimal(%d,3)',
'VCHAR_UNI' => 'varchar(255)',
'VCHAR_UNI:'=> 'varchar(%d)',
'VCHAR_CI' => 'varchar(255)',
'VARBINARY' => 'varbinary(255)',
),

'mysql_40' => array(
'INT:' => 'int(%d)',
'BINT' => 'bigint(20)',
'UINT' => 'mediumint(8) UNSIGNED',
'UINT:' => 'int(%d) UNSIGNED',
'TINT:' => 'tinyint(%d)',
'USINT' => 'smallint(4) UNSIGNED',
'BOOL' => 'tinyint(1) UNSIGNED',
'VCHAR' => 'varbinary(255)',
'VCHAR:' => 'varbinary(%d)',
'CHAR:' => 'binary(%d)',
'XSTEXT' => 'blob',
'XSTEXT_UNI'=> 'blob',
'STEXT' => 'blob',
'STEXT_UNI' => 'blob',
'TEXT' => 'blob',
'TEXT_UNI' => 'blob',
'MTEXT' => 'mediumblob',
'MTEXT_UNI' => 'mediumblob',
'TIMESTAMP' => 'int(11) UNSIGNED',
'DECIMAL' => 'decimal(5,2)',
'DECIMAL:' => 'decimal(%d,2)',
'PDECIMAL' => 'decimal(6,3)',
'PDECIMAL:' => 'decimal(%d,3)',
'VCHAR_UNI' => 'blob',
'VCHAR_UNI:'=> array('varbinary(%d)', 'limit' => array('mult', 3, 255, 'blob')),
'VCHAR_CI' => 'blob',
'VARBINARY' => 'varbinary(255)',
),

'mssql' => array(
'INT:' => '[int]',
'BINT' => '[float]',
'UINT' => '[int]',
'UINT:' => '[int]',
'TINT:' => '[int]',
'USINT' => '[int]',
'BOOL' => '[int]',
'VCHAR' => '[varchar] (255)',
'VCHAR:' => '[varchar] (%d)',
'CHAR:' => '[char] (%d)',
'XSTEXT' => '[varchar] (1000)',
'STEXT' => '[varchar] (3000)',
'TEXT' => '[varchar] (8000)',
'MTEXT' => '[text]',
'XSTEXT_UNI'=> '[varchar] (100)',
'STEXT_UNI' => '[varchar] (255)',
'TEXT_UNI' => '[varchar] (4000)',
'MTEXT_UNI' => '[text]',
'TIMESTAMP' => '[int]',
'DECIMAL' => '[float]',
'DECIMAL:' => '[float]',
'PDECIMAL' => '[float]',
'PDECIMAL:' => '[float]',
'VCHAR_UNI' => '[varchar] (255)',
'VCHAR_UNI:'=> '[varchar] (%d)',
'VCHAR_CI' => '[varchar] (255)',
'VARBINARY' => '[varchar] (255)',
),

'mssqlnative' => array(
'INT:' => '[int]',
'BINT' => '[float]',
'UINT' => '[int]',
'UINT:' => '[int]',
'TINT:' => '[int]',
'USINT' => '[int]',
'BOOL' => '[int]',
'VCHAR' => '[varchar] (255)',
'VCHAR:' => '[varchar] (%d)',
'CHAR:' => '[char] (%d)',
'XSTEXT' => '[varchar] (1000)',
'STEXT' => '[varchar] (3000)',
'TEXT' => '[varchar] (8000)',
'MTEXT' => '[text]',
'XSTEXT_UNI'=> '[varchar] (100)',
'STEXT_UNI' => '[varchar] (255)',
'TEXT_UNI' => '[varchar] (4000)',
'MTEXT_UNI' => '[text]',
'TIMESTAMP' => '[int]',
'DECIMAL' => '[float]',
'DECIMAL:' => '[float]',
'PDECIMAL' => '[float]',
'PDECIMAL:' => '[float]',
'VCHAR_UNI' => '[varchar] (255)',
'VCHAR_UNI:'=> '[varchar] (%d)',
'VCHAR_CI' => '[varchar] (255)',
'VARBINARY' => '[varchar] (255)',
),

'oracle' => array(
'INT:' => 'number(%d)',
'BINT' => 'number(20)',
'UINT' => 'number(8)',
'UINT:' => 'number(%d)',
'TINT:' => 'number(%d)',
'USINT' => 'number(4)',
'BOOL' => 'number(1)',
'VCHAR' => 'varchar2(255)',
'VCHAR:' => 'varchar2(%d)',
'CHAR:' => 'char(%d)',
'XSTEXT' => 'varchar2(1000)',
'STEXT' => 'varchar2(3000)',
'TEXT' => 'clob',
'MTEXT' => 'clob',
'XSTEXT_UNI'=> 'varchar2(300)',
'STEXT_UNI' => 'varchar2(765)',
'TEXT_UNI' => 'clob',
'MTEXT_UNI' => 'clob',
'TIMESTAMP' => 'number(11)',
'DECIMAL' => 'number(5, 2)',
'DECIMAL:' => 'number(%d, 2)',
'PDECIMAL' => 'number(6, 3)',
'PDECIMAL:' => 'number(%d, 3)',
'VCHAR_UNI' => 'varchar2(765)',
'VCHAR_UNI:'=> array('varchar2(%d)', 'limit' => array('mult', 3, 765, 'clob')),
'VCHAR_CI' => 'varchar2(255)',
'VARBINARY' => 'raw(255)',
),

'sqlite' => array(
'INT:' => 'int(%d)',
'BINT' => 'bigint(20)',
'UINT' => 'INTEGER UNSIGNED', //'mediumint(8) UNSIGNED',
'UINT:' => 'INTEGER UNSIGNED', // 'int(%d) UNSIGNED',
'TINT:' => 'tinyint(%d)',
'USINT' => 'INTEGER UNSIGNED', //'mediumint(4) UNSIGNED',
'BOOL' => 'INTEGER UNSIGNED', //'tinyint(1) UNSIGNED',
'VCHAR' => 'varchar(255)',
'VCHAR:' => 'varchar(%d)',
'CHAR:' => 'char(%d)',
'XSTEXT' => 'text(65535)',
'STEXT' => 'text(65535)',
'TEXT' => 'text(65535)',
'MTEXT' => 'mediumtext(16777215)',
'XSTEXT_UNI'=> 'text(65535)',
'STEXT_UNI' => 'text(65535)',
'TEXT_UNI' => 'text(65535)',
'MTEXT_UNI' => 'mediumtext(16777215)',
'TIMESTAMP' => 'INTEGER UNSIGNED', //'int(11) UNSIGNED',
'DECIMAL' => 'decimal(5,2)',
'DECIMAL:' => 'decimal(%d,2)',
'PDECIMAL' => 'decimal(6,3)',
'PDECIMAL:' => 'decimal(%d,3)',
'VCHAR_UNI' => 'varchar(255)',
'VCHAR_UNI:'=> 'varchar(%d)',
'VCHAR_CI' => 'varchar(255)',
'VARBINARY' => 'blob',
),

'sqlite3' => array(
'INT:' => 'INT(%d)',
'BINT' => 'BIGINT(20)',
'UINT' => 'INTEGER UNSIGNED',
'UINT:' => 'INTEGER UNSIGNED',
'TINT:' => 'TINYINT(%d)',
'USINT' => 'INTEGER UNSIGNED',
'BOOL' => 'INTEGER UNSIGNED',
'VCHAR' => 'VARCHAR(255)',
'VCHAR:' => 'VARCHAR(%d)',
'CHAR:' => 'CHAR(%d)',
'XSTEXT' => 'TEXT(65535)',
'STEXT' => 'TEXT(65535)',
'TEXT' => 'TEXT(65535)',
'MTEXT' => 'MEDIUMTEXT(16777215)',
'XSTEXT_UNI'=> 'TEXT(65535)',
'STEXT_UNI' => 'TEXT(65535)',
'TEXT_UNI' => 'TEXT(65535)',
'MTEXT_UNI' => 'MEDIUMTEXT(16777215)',
'TIMESTAMP' => 'INTEGER UNSIGNED', //'int(11) UNSIGNED',
'DECIMAL' => 'DECIMAL(5,2)',
'DECIMAL:' => 'DECIMAL(%d,2)',
'PDECIMAL' => 'DECIMAL(6,3)',
'PDECIMAL:' => 'DECIMAL(%d,3)',
'VCHAR_UNI' => 'VARCHAR(255)',
'VCHAR_UNI:'=> 'VARCHAR(%d)',
'VCHAR_CI' => 'VARCHAR(255)',
'VARBINARY' => 'BLOB',
),

'postgres' => array(
'INT:' => 'INT4',
'BINT' => 'INT8',
'UINT' => 'INT4', // unsigned
'UINT:' => 'INT4', // unsigned
'USINT' => 'INT2', // unsigned
'BOOL' => 'INT2', // unsigned
'TINT:' => 'INT2',
'VCHAR' => 'varchar(255)',
'VCHAR:' => 'varchar(%d)',
'CHAR:' => 'char(%d)',
'XSTEXT' => 'varchar(1000)',
'STEXT' => 'varchar(3000)',
'TEXT' => 'varchar(8000)',
'MTEXT' => 'TEXT',
'XSTEXT_UNI'=> 'varchar(100)',
'STEXT_UNI' => 'varchar(255)',
'TEXT_UNI' => 'varchar(4000)',
'MTEXT_UNI' => 'TEXT',
'TIMESTAMP' => 'INT4', // unsigned
'DECIMAL' => 'decimal(5,2)',
'DECIMAL:' => 'decimal(%d,2)',
'PDECIMAL' => 'decimal(6,3)',
'PDECIMAL:' => 'decimal(%d,3)',
'VCHAR_UNI' => 'varchar(255)',
'VCHAR_UNI:'=> 'varchar(%d)',
'VCHAR_CI' => 'varchar_ci',
'VARBINARY' => 'bytea',
),
);
}

/**
* A list of types being unsigned for better reference in some db's
* @var array
*/
var $unsigned_types = array('UINT', 'UINT:', 'USINT', 'BOOL', 'TIMESTAMP');

/**
* A list of supported DBMS. We change this class to support more DBMS, the DBMS itself only need to follow some rules.
* @var array
*/
var $supported_dbms = array('mssql', 'mssqlnative', 'mysql_40', 'mysql_41', 'oracle', 'postgres', 'sqlite', 'sqlite3');

/**
* This is set to true if user only wants to return the 'to-be-executed' SQL statement(s) (as an array).
* This mode has no effect on some methods (inserting of data for example). This is expressed within the methods command.
*/
var $return_statements = false;

/**
* Constructor. Set DB Object and set {@link $return_statements return_statements}.
*
* @param \phpbb\db\driver\driver_interface $db Database connection
* @param bool $return_statements True if only statements should be returned and no SQL being executed
*/
public function __construct(\phpbb\db\driver\driver_interface $db, $return_statements = false)
{
$this->db = $db;
$this->return_statements = $return_statements;

$this->dbms_type_map = self::get_dbms_type_map();

// Determine mapping database type
switch ($this->db->get_sql_layer())
{
case 'mysql':
$this->sql_layer = 'mysql_40';
break;

case 'mysql4':
if (version_compare($this->db->sql_server_info(true), '4.1.3', '>='))
{
$this->sql_layer = 'mysql_41';
}
else
{
$this->sql_layer = 'mysql_40';
}
break;

case 'mysqli':
$this->sql_layer = 'mysql_41';
break;

case 'mssql':
case 'mssql_odbc':
$this->sql_layer = 'mssql';
break;

case 'mssqlnative':
$this->sql_layer = 'mssqlnative';
break;

default:
$this->sql_layer = $this->db->get_sql_layer();
break;
}
}

/**
* Setter for {@link $return_statements return_statements}.
*
* @param bool $return_statements True if SQL should not be executed but returned as strings
* @return null
*/
public function set_return_statements($return_statements)
{
$this->return_statements = $return_statements;
}

/**
* Gets a list of tables in the database.
*
* @return array Array of table names (all lower case)
*/
function sql_list_tables()
{
switch ($this->db->get_sql_layer())
{
case 'mysql':
case 'mysql4':
case 'mysqli':
$sql = 'SHOW TABLES';
break;

case 'sqlite':
$sql = 'SELECT name
FROM sqlite_master
WHERE type = "table"';
break;

case 'sqlite3':
$sql = 'SELECT name
FROM sqlite_master
WHERE type = "table"
AND name <> "sqlite_sequence"';
break;

case 'mssql':
case 'mssql_odbc':
case 'mssqlnative':
$sql = "SELECT name
FROM sysobjects
WHERE type='U'";
break;

case 'postgres':
$sql = 'SELECT relname
FROM pg_stat_user_tables';
break;

case 'oracle':
$sql = 'SELECT table_name
FROM USER_TABLES';
break;
}

$result = $this->db->sql_query($sql);

$tables = array();
while ($row = $this->db->sql_fetchrow($result))
{
$name = current($row);
$tables[$name] = $name;
}
$this->db->sql_freeresult($result);

return $tables;
}

/**
* Check if table exists
*
*
* @param string $table_name The table name to check for
* @return bool true if table exists, else false
*/
function sql_table_exists($table_name)
{
$this->db->sql_return_on_error(true);
$result = $this->db->sql_query_limit('SELECT * FROM ' . $table_name, 1);
$this->db->sql_return_on_error(false);

if ($result)
{
$this->db->sql_freeresult($result);
return true;
}

return false;
}

/**
* Create SQL Table
*
* @param string $table_name The table name to create
* @param array $table_data Array containing table data.
* @return array Statements if $return_statements is true.
*/
function sql_create_table($table_name, $table_data)
{
// holds the DDL for a column
$columns = $statements = array();

if ($this->sql_table_exists($table_name))
{
return $this->_sql_run_sql($statements);
}

// Begin transaction
$statements[] = 'begin';

// Determine if we have created a PRIMARY KEY in the earliest
$primary_key_gen = false;

// Determine if the table requires a sequence
$create_sequence = false;

// Begin table sql statement
switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
$table_sql = 'CREATE TABLE [' . $table_name . '] (' . "\n";
break;

default:
$table_sql = 'CREATE TABLE ' . $table_name . ' (' . "\n";
break;
}

if ($this->sql_layer == 'mssql' || $this->sql_layer == 'mssqlnative')
{
if (!isset($table_data['PRIMARY_KEY']))
{
$table_data['COLUMNS']['mssqlindex'] = array('UINT', null, 'auto_increment');
$table_data['PRIMARY_KEY'] = 'mssqlindex';
}
}

// Iterate through the columns to create a table
foreach ($table_data['COLUMNS'] as $column_name => $column_data)
{
// here lies an array, filled with information compiled on the column's data
$prepared_column = $this->sql_prepare_column_data($table_name, $column_name, $column_data);

if (isset($prepared_column['auto_increment']) && $prepared_column['auto_increment'] && strlen($column_name) > 26) // "${column_name}_gen"
{
trigger_error("Index name '${column_name}_gen' on table '$table_name' is too long. The maximum auto increment column length is 26 characters.", E_USER_ERROR);
}

// here we add the definition of the new column to the list of columns
switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
$columns[] = "\t [{$column_name}] " . $prepared_column['column_type_sql_default'];
break;

default:
$columns[] = "\t {$column_name} " . $prepared_column['column_type_sql'];
break;
}

// see if we have found a primary key set due to a column definition if we have found it, we can stop looking
if (!$primary_key_gen)
{
$primary_key_gen = isset($prepared_column['primary_key_set']) && $prepared_column['primary_key_set'];
}

// create sequence DDL based off of the existance of auto incrementing columns
if (!$create_sequence && isset($prepared_column['auto_increment']) && $prepared_column['auto_increment'])
{
$create_sequence = $column_name;
}
}

// this makes up all the columns in the create table statement
$table_sql .= implode(",\n", $columns);

// Close the table for two DBMS and add to the statements
switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
$table_sql .= "\n);";
$statements[] = $table_sql;
break;
}

// we have yet to create a primary key for this table,
// this means that we can add the one we really wanted instead
if (!$primary_key_gen)
{
// Write primary key
if (isset($table_data['PRIMARY_KEY']))
{
if (!is_array($table_data['PRIMARY_KEY']))
{
$table_data['PRIMARY_KEY'] = array($table_data['PRIMARY_KEY']);
}

switch ($this->sql_layer)
{
case 'mysql_40':
case 'mysql_41':
case 'postgres':
case 'sqlite':
case 'sqlite3':
$table_sql .= ",\n\t PRIMARY KEY (" . implode(', ', $table_data['PRIMARY_KEY']) . ')';
break;

case 'mssql':
case 'mssqlnative':
// We need the data here
$old_return_statements = $this->return_statements;
$this->return_statements = true;

$primary_key_stmts = $this->sql_create_primary_key($table_name, $table_data['PRIMARY_KEY']);
foreach ($primary_key_stmts as $pk_stmt)
{
$statements[] = $pk_stmt;
}

$this->return_statements = $old_return_statements;
break;

case 'oracle':
$table_sql .= ",\n\t CONSTRAINT pk_{$table_name} PRIMARY KEY (" . implode(', ', $table_data['PRIMARY_KEY']) . ')';
break;
}
}
}

// close the table
switch ($this->sql_layer)
{
case 'mysql_41':
// make sure the table is in UTF-8 mode
$table_sql .= "\n) CHARACTER SET `utf8` COLLATE `utf8_bin`;";
$statements[] = $table_sql;
break;

case 'mysql_40':
case 'sqlite':
case 'sqlite3':
$table_sql .= "\n);";
$statements[] = $table_sql;
break;

case 'postgres':
// do we need to add a sequence for auto incrementing columns?
if ($create_sequence)
{
$statements[] = "CREATE SEQUENCE {$table_name}_seq;";
}

$table_sql .= "\n);";
$statements[] = $table_sql;
break;

case 'oracle':
$table_sql .= "\n)";
$statements[] = $table_sql;

// do we need to add a sequence and a tigger for auto incrementing columns?
if ($create_sequence)
{
// create the actual sequence
$statements[] = "CREATE SEQUENCE {$table_name}_seq";

// the trigger is the mechanism by which we increment the counter
$trigger = "CREATE OR REPLACE TRIGGER t_{$table_name}\n";
$trigger .= "BEFORE INSERT ON {$table_name}\n";
$trigger .= "FOR EACH ROW WHEN (\n";
$trigger .= "\tnew.{$create_sequence} IS NULL OR new.{$create_sequence} = 0\n";
$trigger .= ")\n";
$trigger .= "BEGIN\n";
$trigger .= "\tSELECT {$table_name}_seq.nextval\n";
$trigger .= "\tINTO :new.{$create_sequence}\n";
$trigger .= "\tFROM dual;\n";
$trigger .= "END;";

$statements[] = $trigger;
}
break;
}

// Write Keys
if (isset($table_data['KEYS']))
{
foreach ($table_data['KEYS'] as $key_name => $key_data)
{
if (!is_array($key_data[1]))
{
$key_data[1] = array($key_data[1]);
}

$old_return_statements = $this->return_statements;
$this->return_statements = true;

$key_stmts = ($key_data[0] == 'UNIQUE') ? $this->sql_create_unique_index($table_name, $key_name, $key_data[1]) : $this->sql_create_index($table_name, $key_name, $key_data[1]);

foreach ($key_stmts as $key_stmt)
{
$statements[] = $key_stmt;
}

$this->return_statements = $old_return_statements;
}
}

// Commit Transaction
$statements[] = 'commit';

return $this->_sql_run_sql($statements);
}

/**
* Handle passed database update array.
* Expected structure...
* Key being one of the following
* drop_tables: Drop tables
* add_tables: Add tables
* change_columns: Column changes (only type, not name)
* add_columns: Add columns to a table
* drop_keys: Dropping keys
* drop_columns: Removing/Dropping columns
* add_primary_keys: adding primary keys
* add_unique_index: adding an unique index
* add_index: adding an index (can be column:index_size if you need to provide size)
*
* The values are in this format:
* {TABLE NAME} => array(
* {COLUMN NAME} => array({COLUMN TYPE}, {DEFAULT VALUE}, {OPTIONAL VARIABLES}),
* {KEY/INDEX NAME} => array({COLUMN NAMES}),
* )
*
* For more information have a look at /develop/create_schema_files.php (only available through SVN)
*/
function perform_schema_changes($schema_changes)
{
if (empty($schema_changes))
{
return;
}

$statements = array();
$sqlite = false;

// For SQLite we need to perform the schema changes in a much more different way
if (($this->db->get_sql_layer() == 'sqlite' || $this->db->get_sql_layer() == 'sqlite3') && $this->return_statements)
{
$sqlite_data = array();
$sqlite = true;
}

// Drop tables?
if (!empty($schema_changes['drop_tables']))
{
foreach ($schema_changes['drop_tables'] as $table)
{
// only drop table if it exists
if ($this->sql_table_exists($table))
{
$result = $this->sql_table_drop($table);
if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}
}

// Add tables?
if (!empty($schema_changes['add_tables']))
{
foreach ($schema_changes['add_tables'] as $table => $table_data)
{
$result = $this->sql_create_table($table, $table_data);
if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}

// Change columns?
if (!empty($schema_changes['change_columns']))
{
foreach ($schema_changes['change_columns'] as $table => $columns)
{
foreach ($columns as $column_name => $column_data)
{
// If the column exists we change it, else we add it ;)
if ($column_exists = $this->sql_column_exists($table, $column_name))
{
$result = $this->sql_column_change($table, $column_name, $column_data, true);
}
else
{
$result = $this->sql_column_add($table, $column_name, $column_data, true);
}

if ($sqlite)
{
if ($column_exists)
{
$sqlite_data[$table]['change_columns'][] = $result;
}
else
{
$sqlite_data[$table]['add_columns'][] = $result;
}
}
else if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}
}

// Add columns?
if (!empty($schema_changes['add_columns']))
{
foreach ($schema_changes['add_columns'] as $table => $columns)
{
foreach ($columns as $column_name => $column_data)
{
// Only add the column if it does not exist yet
if ($column_exists = $this->sql_column_exists($table, $column_name))
{
continue;
// This is commented out here because it can take tremendous time on updates
// $result = $this->sql_column_change($table, $column_name, $column_data, true);
}
else
{
$result = $this->sql_column_add($table, $column_name, $column_data, true);
}

if ($sqlite)
{
if ($column_exists)
{
continue;
// $sqlite_data[$table]['change_columns'][] = $result;
}
else
{
$sqlite_data[$table]['add_columns'][] = $result;
}
}
else if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}
}

// Remove keys?
if (!empty($schema_changes['drop_keys']))
{
foreach ($schema_changes['drop_keys'] as $table => $indexes)
{
foreach ($indexes as $index_name)
{
if (!$this->sql_index_exists($table, $index_name))
{
continue;
}

$result = $this->sql_index_drop($table, $index_name);

if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}
}

// Drop columns?
if (!empty($schema_changes['drop_columns']))
{
foreach ($schema_changes['drop_columns'] as $table => $columns)
{
foreach ($columns as $column)
{
// Only remove the column if it exists...
if ($this->sql_column_exists($table, $column))
{
$result = $this->sql_column_remove($table, $column, true);

if ($sqlite)
{
$sqlite_data[$table]['drop_columns'][] = $result;
}
else if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}
}
}

// Add primary keys?
if (!empty($schema_changes['add_primary_keys']))
{
foreach ($schema_changes['add_primary_keys'] as $table => $columns)
{
$result = $this->sql_create_primary_key($table, $columns, true);

if ($sqlite)
{
$sqlite_data[$table]['primary_key'] = $result;
}
else if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}

// Add unique indexes?
if (!empty($schema_changes['add_unique_index']))
{
foreach ($schema_changes['add_unique_index'] as $table => $index_array)
{
foreach ($index_array as $index_name => $column)
{
if ($this->sql_unique_index_exists($table, $index_name))
{
continue;
}

$result = $this->sql_create_unique_index($table, $index_name, $column);

if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}
}

// Add indexes?
if (!empty($schema_changes['add_index']))
{
foreach ($schema_changes['add_index'] as $table => $index_array)
{
foreach ($index_array as $index_name => $column)
{
if ($this->sql_index_exists($table, $index_name))
{
continue;
}

$result = $this->sql_create_index($table, $index_name, $column);

if ($this->return_statements)
{
$statements = array_merge($statements, $result);
}
}
}
}

if ($sqlite)
{
foreach ($sqlite_data as $table_name => $sql_schema_changes)
{
// Create temporary table with original data
$statements[] = 'begin';

$sql = "SELECT sql
FROM sqlite_master
WHERE type = 'table'
AND name = '{$table_name}'
ORDER BY type DESC, name;";
$result = $this->db->sql_query($sql);

if (!$result)
{
continue;
}

$row = $this->db->sql_fetchrow($result);
$this->db->sql_freeresult($result);

// Create a backup table and populate it, destroy the existing one
$statements[] = preg_replace('#CREATE\s+TABLE\s+"?' . $table_name . '"?#i', 'CREATE TEMPORARY TABLE ' . $table_name . '_temp', $row['sql']);
$statements[] = 'INSERT INTO ' . $table_name . '_temp SELECT * FROM ' . $table_name;
$statements[] = 'DROP TABLE ' . $table_name;

// Get the columns...
preg_match('#\((.*)\)#s', $row['sql'], $matches);

$plain_table_cols = trim($matches[1]);
$new_table_cols = preg_split('/,(?![\s\w]+\))/m', $plain_table_cols);
$column_list = array();

foreach ($new_table_cols as $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if ($entities[0] == 'PRIMARY')
{
continue;
}
$column_list[] = $entities[0];
}

// note down the primary key notation because sqlite only supports adding it to the end for the new table
$primary_key = false;
$_new_cols = array();

foreach ($new_table_cols as $key => $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if ($entities[0] == 'PRIMARY')
{
$primary_key = $declaration;
continue;
}
$_new_cols[] = $declaration;
}

$new_table_cols = $_new_cols;

// First of all... change columns
if (!empty($sql_schema_changes['change_columns']))
{
foreach ($sql_schema_changes['change_columns'] as $column_sql)
{
foreach ($new_table_cols as $key => $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if (strpos($column_sql, $entities[0] . ' ') === 0)
{
$new_table_cols[$key] = $column_sql;
}
}
}
}

if (!empty($sql_schema_changes['add_columns']))
{
foreach ($sql_schema_changes['add_columns'] as $column_sql)
{
$new_table_cols[] = $column_sql;
}
}

// Now drop them...
if (!empty($sql_schema_changes['drop_columns']))
{
foreach ($sql_schema_changes['drop_columns'] as $column_name)
{
// Remove from column list...
$new_column_list = array();
foreach ($column_list as $key => $value)
{
if ($value === $column_name)
{
continue;
}

$new_column_list[] = $value;
}

$column_list = $new_column_list;

// Remove from table...
$_new_cols = array();
foreach ($new_table_cols as $key => $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if (strpos($column_name . ' ', $entities[0] . ' ') === 0)
{
continue;
}
$_new_cols[] = $declaration;
}
$new_table_cols = $_new_cols;
}
}

// Primary key...
if (!empty($sql_schema_changes['primary_key']))
{
$new_table_cols[] = 'PRIMARY KEY (' . implode(', ', $sql_schema_changes['primary_key']) . ')';
}
// Add a new one or the old primary key
else if ($primary_key !== false)
{
$new_table_cols[] = $primary_key;
}

$columns = implode(',', $column_list);

// create a new table and fill it up. destroy the temp one
$statements[] = 'CREATE TABLE ' . $table_name . ' (' . implode(',', $new_table_cols) . ');';
$statements[] = 'INSERT INTO ' . $table_name . ' (' . $columns . ') SELECT ' . $columns . ' FROM ' . $table_name . '_temp;';
$statements[] = 'DROP TABLE ' . $table_name . '_temp';

$statements[] = 'commit';
}
}

if ($this->return_statements)
{
return $statements;
}
}

/**
* Gets a list of columns of a table.
*
* @param string $table Table name
*
* @return array Array of column names (all lower case)
*/
function sql_list_columns($table)
{
$columns = array();

switch ($this->sql_layer)
{
case 'mysql_40':
case 'mysql_41':
$sql = "SHOW COLUMNS FROM $table";
break;

// PostgreSQL has a way of doing this in a much simpler way but would
// not allow us to support all versions of PostgreSQL
case 'postgres':
$sql = "SELECT a.attname
FROM pg_class c, pg_attribute a
WHERE c.relname = '{$table}'
AND a.attnum > 0
AND a.attrelid = c.oid";
break;

// same deal with PostgreSQL, we must perform more complex operations than
// we technically could
case 'mssql':
case 'mssqlnative':
$sql = "SELECT c.name
FROM syscolumns c
LEFT JOIN sysobjects o ON c.id = o.id
WHERE o.name = '{$table}'";
break;

case 'oracle':
$sql = "SELECT column_name
FROM user_tab_columns
WHERE LOWER(table_name) = '" . strtolower($table) . "'";
break;

case 'sqlite':
case 'sqlite3':
$sql = "SELECT sql
FROM sqlite_master
WHERE type = 'table'
AND name = '{$table}'";

$result = $this->db->sql_query($sql);

if (!$result)
{
return false;
}

$row = $this->db->sql_fetchrow($result);
$this->db->sql_freeresult($result);

preg_match('#\((.*)\)#s', $row['sql'], $matches);

$cols = trim($matches[1]);
$col_array = preg_split('/,(?![\s\w]+\))/m', $cols);

foreach ($col_array as $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if ($entities[0] == 'PRIMARY')
{
continue;
}

$column = strtolower($entities[0]);
$columns[$column] = $column;
}

return $columns;
break;
}

$result = $this->db->sql_query($sql);

while ($row = $this->db->sql_fetchrow($result))
{
$column = strtolower(current($row));
$columns[$column] = $column;
}
$this->db->sql_freeresult($result);

return $columns;
}

/**
* Check whether a specified column exist in a table
*
* @param string $table Table to check
* @param string $column_name Column to check
*
* @return bool True if column exists, false otherwise
*/
function sql_column_exists($table, $column_name)
{
$columns = $this->sql_list_columns($table);

return isset($columns[$column_name]);
}

/**
* Check if a specified index exists in table. Does not return PRIMARY KEY and UNIQUE indexes.
*
* @param string $table_name Table to check the index at
* @param string $index_name The index name to check
*
* @return bool True if index exists, else false
*/
function sql_index_exists($table_name, $index_name)
{
if ($this->sql_layer == 'mssql' || $this->sql_layer == 'mssqlnative')
{
$sql = "EXEC sp_statistics '$table_name'";
$result = $this->db->sql_query($sql);

while ($row = $this->db->sql_fetchrow($result))
{
if ($row['TYPE'] == 3)
{
if (strtolower($row['INDEX_NAME']) == strtolower($index_name))
{
$this->db->sql_freeresult($result);
return true;
}
}
}
$this->db->sql_freeresult($result);

return false;
}

switch ($this->sql_layer)
{
case 'postgres':
$sql = "SELECT ic.relname as index_name
FROM pg_class bc, pg_class ic, pg_index i
WHERE (bc.oid = i.indrelid)
AND (ic.oid = i.indexrelid)
AND (bc.relname = '" . $table_name . "')
AND (i.indisunique != 't')
AND (i.indisprimary != 't')";
$col = 'index_name';
break;

case 'mysql_40':
case 'mysql_41':
$sql = 'SHOW KEYS
FROM ' . $table_name;
$col = 'Key_name';
break;

case 'oracle':
$sql = "SELECT index_name
FROM user_indexes
WHERE table_name = '" . strtoupper($table_name) . "'
AND generated = 'N'
AND uniqueness = 'NONUNIQUE'";
$col = 'index_name';
break;

case 'sqlite':
case 'sqlite3':
$sql = "PRAGMA index_list('" . $table_name . "');";
$col = 'name';
break;
}

$result = $this->db->sql_query($sql);
while ($row = $this->db->sql_fetchrow($result))
{
if (($this->sql_layer == 'mysql_40' || $this->sql_layer == 'mysql_41') && !$row['Non_unique'])
{
continue;
}

// These DBMS prefix index name with the table name
switch ($this->sql_layer)
{
case 'oracle':
case 'postgres':
case 'sqlite':
case 'sqlite3':
$row[$col] = substr($row[$col], strlen($table_name) + 1);
break;
}

if (strtolower($row[$col]) == strtolower($index_name))
{
$this->db->sql_freeresult($result);
return true;
}
}
$this->db->sql_freeresult($result);

return false;
}

/**
* Check if a specified index exists in table. Does not return PRIMARY KEY indexes.
*
* @param string $table_name Table to check the index at
* @param string $index_name The index name to check
*
* @return bool True if index exists, else false
*/
function sql_unique_index_exists($table_name, $index_name)
{
if ($this->sql_layer == 'mssql' || $this->sql_layer == 'mssqlnative')
{
$sql = "EXEC sp_statistics '$table_name'";
$result = $this->db->sql_query($sql);

while ($row = $this->db->sql_fetchrow($result))
{
// Usually NON_UNIQUE is the column we want to check, but we allow for both
if ($row['TYPE'] == 3)
{
if (strtolower($row['INDEX_NAME']) == strtolower($index_name))
{
$this->db->sql_freeresult($result);
return true;
}
}
}
$this->db->sql_freeresult($result);
return false;
}

switch ($this->sql_layer)
{
case 'postgres':
$sql = "SELECT ic.relname as index_name, i.indisunique
FROM pg_class bc, pg_class ic, pg_index i
WHERE (bc.oid = i.indrelid)
AND (ic.oid = i.indexrelid)
AND (bc.relname = '" . $table_name . "')
AND (i.indisprimary != 't')";
$col = 'index_name';
break;

case 'mysql_40':
case 'mysql_41':
$sql = 'SHOW KEYS
FROM ' . $table_name;
$col = 'Key_name';
break;

case 'oracle':
$sql = "SELECT index_name, table_owner
FROM user_indexes
WHERE table_name = '" . strtoupper($table_name) . "'
AND generated = 'N'
AND uniqueness = 'UNIQUE'";
$col = 'index_name';
break;

case 'sqlite':
case 'sqlite3':
$sql = "PRAGMA index_list('" . $table_name . "');";
$col = 'name';
break;
}

$result = $this->db->sql_query($sql);
while ($row = $this->db->sql_fetchrow($result))
{
if (($this->sql_layer == 'mysql_40' || $this->sql_layer == 'mysql_41') && ($row['Non_unique'] || $row[$col] == 'PRIMARY'))
{
continue;
}

if (($this->sql_layer == 'sqlite' || $this->sql_layer == 'sqlite3') && !$row['unique'])
{
continue;
}

if ($this->sql_layer == 'postgres' && $row['indisunique'] != 't')
{
continue;
}

// These DBMS prefix index name with the table name
switch ($this->sql_layer)
{
case 'oracle':
// Two cases here... prefixed with U_[table_owner] and not prefixed with table_name
if (strpos($row[$col], 'U_') === 0)
{
$row[$col] = substr($row[$col], strlen('U_' . $row['table_owner']) + 1);
}
else if (strpos($row[$col], strtoupper($table_name)) === 0)
{
$row[$col] = substr($row[$col], strlen($table_name) + 1);
}
break;

case 'postgres':
case 'sqlite':
case 'sqlite3':
$row[$col] = substr($row[$col], strlen($table_name) + 1);
break;
}

if (strtolower($row[$col]) == strtolower($index_name))
{
$this->db->sql_freeresult($result);
return true;
}
}
$this->db->sql_freeresult($result);

return false;
}

/**
* Private method for performing sql statements (either execute them or return them)
* @access private
*/
function _sql_run_sql($statements)
{
if ($this->return_statements)
{
return $statements;
}

// We could add error handling here...
foreach ($statements as $sql)
{
if ($sql === 'begin')
{
$this->db->sql_transaction('begin');
}
else if ($sql === 'commit')
{
$this->db->sql_transaction('commit');
}
else
{
$this->db->sql_query($sql);
}
}

return true;
}

/**
* Function to prepare some column information for better usage
* @access private
*/
function sql_prepare_column_data($table_name, $column_name, $column_data)
{
if (strlen($column_name) > 30)
{
trigger_error("Column name '$column_name' on table '$table_name' is too long. The maximum is 30 characters.", E_USER_ERROR);
}

// Get type
list($column_type, $orig_column_type) = $this->get_column_type($column_data[0]);

// Adjust default value if db-dependent specified
if (is_array($column_data[1]))
{
$column_data[1] = (isset($column_data[1][$this->sql_layer])) ? $column_data[1][$this->sql_layer] : $column_data[1]['default'];
}

$sql = '';

$return_array = array();

switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
$sql .= " {$column_type} ";
$sql_default = " {$column_type} ";

// For adding columns we need the default definition
if (!is_null($column_data[1]))
{
// For hexadecimal values do not use single quotes
if (strpos($column_data[1], '0x') === 0)
{
$return_array['default'] = 'DEFAULT (' . $column_data[1] . ') ';
$sql_default .= $return_array['default'];
}
else
{
$return_array['default'] = 'DEFAULT (' . ((is_numeric($column_data[1])) ? $column_data[1] : "'{$column_data[1]}'") . ') ';
$sql_default .= $return_array['default'];
}
}

if (isset($column_data[2]) && $column_data[2] == 'auto_increment')
{
// $sql .= 'IDENTITY (1, 1) ';
$sql_default .= 'IDENTITY (1, 1) ';
}

$return_array['textimage'] = $column_type === '[text]';

if (!is_null($column_data[1]) || (isset($column_data[2]) && $column_data[2] == 'auto_increment'))
{
$sql .= 'NOT NULL';
$sql_default .= 'NOT NULL';
}
else
{
$sql .= 'NULL';
$sql_default .= 'NULL';
}

$return_array['column_type_sql_default'] = $sql_default;

break;

case 'mysql_40':
case 'mysql_41':
$sql .= " {$column_type} ";

// For hexadecimal values do not use single quotes
if (!is_null($column_data[1]) && substr($column_type, -4) !== 'text' && substr($column_type, -4) !== 'blob')
{
$sql .= (strpos($column_data[1], '0x') === 0) ? "DEFAULT {$column_data[1]} " : "DEFAULT '{$column_data[1]}' ";
}

if (!is_null($column_data[1]) || (isset($column_data[2]) && $column_data[2] == 'auto_increment'))
{
$sql .= 'NOT NULL';
}
else
{
$sql .= 'NULL';
}

if (isset($column_data[2]))
{
if ($column_data[2] == 'auto_increment')
{
$sql .= ' auto_increment';
}
else if ($this->sql_layer === 'mysql_41' && $column_data[2] == 'true_sort')
{
$sql .= ' COLLATE utf8_unicode_ci';
}
}

break;

case 'oracle':
$sql .= " {$column_type} ";
$sql .= (!is_null($column_data[1])) ? "DEFAULT '{$column_data[1]}' " : '';

// In Oracle empty strings ('') are treated as NULL.
// Therefore in oracle we allow NULL's for all DEFAULT '' entries
// Oracle does not like setting NOT NULL on a column that is already NOT NULL (this happens only on number fields)
if (!preg_match('/number/i', $column_type))
{
$sql .= ($column_data[1] === '' || $column_data[1] === null) ? '' : 'NOT NULL';
}

$return_array['auto_increment'] = false;
if (isset($column_data[2]) && $column_data[2] == 'auto_increment')
{
$return_array['auto_increment'] = true;
}

break;

case 'postgres':
$return_array['column_type'] = $column_type;

$sql .= " {$column_type} ";

$return_array['auto_increment'] = false;
if (isset($column_data[2]) && $column_data[2] == 'auto_increment')
{
$default_val = "nextval('{$table_name}_seq')";
$return_array['auto_increment'] = true;
}
else if (!is_null($column_data[1]))
{
$default_val = "'" . $column_data[1] . "'";
$return_array['null'] = 'NOT NULL';
$sql .= 'NOT NULL ';
}
else
{
$default_val = "'" . $column_data[1] . "'";
$return_array['null'] = 'NULL';
$sql .= 'NULL ';
}

$return_array['default'] = $default_val;

$sql .= "DEFAULT {$default_val}";

// Unsigned? Then add a CHECK contraint
if (in_array($orig_column_type, $this->unsigned_types))
{
$return_array['constraint'] = "CHECK ({$column_name} >= 0)";
$sql .= " CHECK ({$column_name} >= 0)";
}

break;

case 'sqlite':
case 'sqlite3':
$return_array['primary_key_set'] = false;
if (isset($column_data[2]) && $column_data[2] == 'auto_increment')
{
$sql .= ' INTEGER PRIMARY KEY';
$return_array['primary_key_set'] = true;

if ($this->sql_layer === 'sqlite3')
{
$sql .= ' AUTOINCREMENT';
}
}
else
{
$sql .= ' ' . $column_type;
}

if (!is_null($column_data[1]))
{
$sql .= ' NOT NULL ';
$sql .= "DEFAULT '{$column_data[1]}'";
}

break;
}

$return_array['column_type_sql'] = $sql;

return $return_array;
}

/**
* Get the column's database type from the type map
*
* @param string $column_map_type
* @return array column type for this database
* and map type without length
*/
function get_column_type($column_map_type)
{
if (strpos($column_map_type, ':') !== false)
{
list($orig_column_type, $column_length) = explode(':', $column_map_type);
if (!is_array($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']))
{
$column_type = sprintf($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':'], $column_length);
}
else
{
if (isset($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['rule']))
{
switch ($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['rule'][0])
{
case 'div':
$column_length /= $this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['rule'][1];
$column_length = ceil($column_length);
$column_type = sprintf($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':'][0], $column_length);
break;
}
}

if (isset($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['limit']))
{
switch ($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['limit'][0])
{
case 'mult':
$column_length *= $this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['limit'][1];
if ($column_length > $this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['limit'][2])
{
$column_type = $this->dbms_type_map[$this->sql_layer][$orig_column_type . ':']['limit'][3];
}
else
{
$column_type = sprintf($this->dbms_type_map[$this->sql_layer][$orig_column_type . ':'][0], $column_length);
}
break;
}
}
}
$orig_column_type .= ':';
}
else
{
$orig_column_type = $column_map_type;
$column_type = $this->dbms_type_map[$this->sql_layer][$column_map_type];
}

return array($column_type, $orig_column_type);
}

/**
* Add new column
*/
function sql_column_add($table_name, $column_name, $column_data, $inline = false)
{
$column_data = $this->sql_prepare_column_data($table_name, $column_name, $column_data);
$statements = array();

switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
// Does not support AFTER, only through temporary table
$statements[] = 'ALTER TABLE [' . $table_name . '] ADD [' . $column_name . '] ' . $column_data['column_type_sql_default'];
break;

case 'mysql_40':
case 'mysql_41':
$after = (!empty($column_data['after'])) ? ' AFTER ' . $column_data['after'] : '';
$statements[] = 'ALTER TABLE `' . $table_name . '` ADD COLUMN `' . $column_name . '` ' . $column_data['column_type_sql'] . $after;
break;

case 'oracle':
// Does not support AFTER, only through temporary table
$statements[] = 'ALTER TABLE ' . $table_name . ' ADD ' . $column_name . ' ' . $column_data['column_type_sql'];
break;

case 'postgres':
// Does not support AFTER, only through temporary table
if (version_compare($this->db->sql_server_info(true), '8.0', '>='))
{
$statements[] = 'ALTER TABLE ' . $table_name . ' ADD COLUMN "' . $column_name . '" ' . $column_data['column_type_sql'];
}
else
{
// old versions cannot add columns with default and null information
$statements[] = 'ALTER TABLE ' . $table_name . ' ADD COLUMN "' . $column_name . '" ' . $column_data['column_type'] . ' ' . $column_data['constraint'];

if (isset($column_data['null']))
{
if ($column_data['null'] == 'NOT NULL')
{
$statements[] = 'ALTER TABLE ' . $table_name . ' ALTER COLUMN ' . $column_name . ' SET NOT NULL';
}
}

if (isset($column_data['default']))
{
$statements[] = 'ALTER TABLE ' . $table_name . ' ALTER COLUMN ' . $column_name . ' SET DEFAULT ' . $column_data['default'];
}
}

break;

case 'sqlite':
if ($inline && $this->return_statements)
{
return $column_name . ' ' . $column_data['column_type_sql'];
}

$recreate_queries = $this->sqlite_get_recreate_table_queries($table_name);
if (empty($recreate_queries))
{
break;
}

$statements[] = 'begin';

$sql_create_table = array_shift($recreate_queries);

// Create a backup table and populate it, destroy the existing one
$statements[] = preg_replace('#CREATE\s+TABLE\s+"?' . $table_name . '"?#i', 'CREATE TEMPORARY TABLE ' . $table_name . '_temp', $sql_create_table);
$statements[] = 'INSERT INTO ' . $table_name . '_temp SELECT * FROM ' . $table_name;
$statements[] = 'DROP TABLE ' . $table_name;

preg_match('#\((.*)\)#s', $sql_create_table, $matches);

$new_table_cols = trim($matches[1]);
$old_table_cols = preg_split('/,(?![\s\w]+\))/m', $new_table_cols);
$column_list = array();

foreach ($old_table_cols as $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if ($entities[0] == 'PRIMARY')
{
continue;
}
$column_list[] = $entities[0];
}

$columns = implode(',', $column_list);

$new_table_cols = $column_name . ' ' . $column_data['column_type_sql'] . ',' . $new_table_cols;

// create a new table and fill it up. destroy the temp one
$statements[] = 'CREATE TABLE ' . $table_name . ' (' . $new_table_cols . ');';
$statements = array_merge($statements, $recreate_queries);

$statements[] = 'INSERT INTO ' . $table_name . ' (' . $columns . ') SELECT ' . $columns . ' FROM ' . $table_name . '_temp;';
$statements[] = 'DROP TABLE ' . $table_name . '_temp';

$statements[] = 'commit';
break;

case 'sqlite3':
if ($inline && $this->return_statements)
{
return $column_name . ' ' . $column_data['column_type_sql'];
}

$statements[] = 'ALTER TABLE ' . $table_name . ' ADD ' . $column_name . ' ' . $column_data['column_type_sql'];
break;
}

return $this->_sql_run_sql($statements);
}

/**
* Drop column
*/
function sql_column_remove($table_name, $column_name, $inline = false)
{
$statements = array();

switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
// We need the data here
$old_return_statements = $this->return_statements;
$this->return_statements = true;

$indexes = $this->get_existing_indexes($table_name, $column_name);
$indexes = array_merge($indexes, $this->get_existing_indexes($table_name, $column_name, true));

// Drop any indexes
$recreate_indexes = array();
if (!empty($indexes))
{
foreach ($indexes as $index_name => $index_data)
{
$result = $this->sql_index_drop($table_name, $index_name);
$statements = array_merge($statements, $result);
if (sizeof($index_data) > 1)
{
// Remove this column from the index and recreate it
$recreate_indexes[$index_name] = array_diff($index_data, array($column_name));
}
}
}

// Drop default value constraint
$result = $this->mssql_get_drop_default_constraints_queries($table_name, $column_name);
$statements = array_merge($statements, $result);

// Remove the column
$statements[] = 'ALTER TABLE [' . $table_name . '] DROP COLUMN [' . $column_name . ']';

if (!empty($recreate_indexes))
{
// Recreate indexes after we removed the column
foreach ($recreate_indexes as $index_name => $index_data)
{
$result = $this->sql_create_index($table_name, $index_name, $index_data);
$statements = array_merge($statements, $result);
}
}

$this->return_statements = $old_return_statements;
break;

case 'mysql_40':
case 'mysql_41':
$statements[] = 'ALTER TABLE `' . $table_name . '` DROP COLUMN `' . $column_name . '`';
break;

case 'oracle':
$statements[] = 'ALTER TABLE ' . $table_name . ' DROP COLUMN ' . $column_name;
break;

case 'postgres':
$statements[] = 'ALTER TABLE ' . $table_name . ' DROP COLUMN "' . $column_name . '"';
break;

case 'sqlite':
case 'sqlite3':

if ($inline && $this->return_statements)
{
return $column_name;
}

$recreate_queries = $this->sqlite_get_recreate_table_queries($table_name, $column_name);
if (empty($recreate_queries))
{
break;
}

$statements[] = 'begin';

$sql_create_table = array_shift($recreate_queries);

// Create a backup table and populate it, destroy the existing one
$statements[] = preg_replace('#CREATE\s+TABLE\s+"?' . $table_name . '"?#i', 'CREATE TEMPORARY TABLE ' . $table_name . '_temp', $sql_create_table);
$statements[] = 'INSERT INTO ' . $table_name . '_temp SELECT * FROM ' . $table_name;
$statements[] = 'DROP TABLE ' . $table_name;

preg_match('#\((.*)\)#s', $sql_create_table, $matches);

$new_table_cols = trim($matches[1]);
$old_table_cols = preg_split('/,(?![\s\w]+\))/m', $new_table_cols);
$column_list = array();

foreach ($old_table_cols as $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if ($entities[0] == 'PRIMARY' || $entities[0] === $column_name)
{
continue;
}
$column_list[] = $entities[0];
}

$columns = implode(',', $column_list);

$new_table_cols = trim(preg_replace('/' . $column_name . '\b[^,]+(?:,|$)/m', '', $new_table_cols));
if (substr($new_table_cols, -1) === ',')
{
// Remove the comma from the last entry again
$new_table_cols = substr($new_table_cols, 0, -1);
}

// create a new table and fill it up. destroy the temp one
$statements[] = 'CREATE TABLE ' . $table_name . ' (' . $new_table_cols . ');';
$statements = array_merge($statements, $recreate_queries);

$statements[] = 'INSERT INTO ' . $table_name . ' (' . $columns . ') SELECT ' . $columns . ' FROM ' . $table_name . '_temp;';
$statements[] = 'DROP TABLE ' . $table_name . '_temp';

$statements[] = 'commit';
break;
}

return $this->_sql_run_sql($statements);
}

/**
* Drop Index
*/
function sql_index_drop($table_name, $index_name)
{
$statements = array();

switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
$statements[] = 'DROP INDEX ' . $table_name . '.' . $index_name;
break;

case 'mysql_40':
case 'mysql_41':
$statements[] = 'DROP INDEX ' . $index_name . ' ON ' . $table_name;
break;

case 'oracle':
case 'postgres':
case 'sqlite':
case 'sqlite3':
$statements[] = 'DROP INDEX ' . $table_name . '_' . $index_name;
break;
}

return $this->_sql_run_sql($statements);
}

/**
* Drop Table
*/
function sql_table_drop($table_name)
{
$statements = array();

if (!$this->sql_table_exists($table_name))
{
return $this->_sql_run_sql($statements);
}

// the most basic operation, get rid of the table
$statements[] = 'DROP TABLE ' . $table_name;

switch ($this->sql_layer)
{
case 'oracle':
$sql = 'SELECT A.REFERENCED_NAME
FROM USER_DEPENDENCIES A, USER_TRIGGERS B
WHERE A.REFERENCED_TYPE = \'SEQUENCE\'
AND A.NAME = B.TRIGGER_NAME
AND B.TABLE_NAME = \'' . strtoupper($table_name) . "'";
$result = $this->db->sql_query($sql);

// any sequences ref'd to this table's triggers?
while ($row = $this->db->sql_fetchrow($result))
{
$statements[] = "DROP SEQUENCE {$row['referenced_name']}";
}
$this->db->sql_freeresult($result);
break;

case 'postgres':
// PGSQL does not "tightly" bind sequences and tables, we must guess...
$sql = "SELECT relname
FROM pg_class
WHERE relkind = 'S'
AND relname = '{$table_name}_seq'";
$result = $this->db->sql_query($sql);

// We don't even care about storing the results. We already know the answer if we get rows back.
if ($this->db->sql_fetchrow($result))
{
$statements[] = "DROP SEQUENCE {$table_name}_seq;\n";
}
$this->db->sql_freeresult($result);
break;
}

return $this->_sql_run_sql($statements);
}

/**
* Add primary key
*/
function sql_create_primary_key($table_name, $column, $inline = false)
{
$statements = array();

switch ($this->sql_layer)
{
case 'postgres':
case 'mysql_40':
case 'mysql_41':
$statements[] = 'ALTER TABLE ' . $table_name . ' ADD PRIMARY KEY (' . implode(', ', $column) . ')';
break;

case 'mssql':
case 'mssqlnative':
$sql = "ALTER TABLE [{$table_name}] WITH NOCHECK ADD ";
$sql .= "CONSTRAINT [PK_{$table_name}] PRIMARY KEY CLUSTERED (";
$sql .= '[' . implode("],\n\t\t[", $column) . ']';
$sql .= ')';

$statements[] = $sql;
break;

case 'oracle':
$statements[] = 'ALTER TABLE ' . $table_name . ' add CONSTRAINT pk_' . $table_name . ' PRIMARY KEY (' . implode(', ', $column) . ')';
break;

case 'sqlite':
case 'sqlite3':

if ($inline && $this->return_statements)
{
return $column;
}

$recreate_queries = $this->sqlite_get_recreate_table_queries($table_name);
if (empty($recreate_queries))
{
break;
}

$statements[] = 'begin';

$sql_create_table = array_shift($recreate_queries);

// Create a backup table and populate it, destroy the existing one
$statements[] = preg_replace('#CREATE\s+TABLE\s+"?' . $table_name . '"?#i', 'CREATE TEMPORARY TABLE ' . $table_name . '_temp', $sql_create_table);
$statements[] = 'INSERT INTO ' . $table_name . '_temp SELECT * FROM ' . $table_name;
$statements[] = 'DROP TABLE ' . $table_name;

preg_match('#\((.*)\)#s', $sql_create_table, $matches);

$new_table_cols = trim($matches[1]);
$old_table_cols = preg_split('/,(?![\s\w]+\))/m', $new_table_cols);
$column_list = array();

foreach ($old_table_cols as $declaration)
{
$entities = preg_split('#\s+#', trim($declaration));
if ($entities[0] == 'PRIMARY')
{
continue;
}
$column_list[] = $entities[0];
}

$columns = implode(',', $column_list);

// create a new table and fill it up. destroy the temp one
$statements[] = 'CREATE TABLE ' . $table_name . ' (' . $new_table_cols . ', PRIMARY KEY (' . implode(', ', $column) . '));';
$statements = array_merge($statements, $recreate_queries);

$statements[] = 'INSERT INTO ' . $table_name . ' (' . $columns . ') SELECT ' . $columns . ' FROM ' . $table_name . '_temp;';
$statements[] = 'DROP TABLE ' . $table_name . '_temp';

$statements[] = 'commit';
break;
}

return $this->_sql_run_sql($statements);
}

/**
* Add unique index
*/
function sql_create_unique_index($table_name, $index_name, $column)
{
$statements = array();

$table_prefix = substr(CONFIG_TABLE, 0, -6); // strlen(config)
if (strlen($table_name . '_' . $index_name) - strlen($table_prefix) > 24)
{
$max_length = strlen($table_prefix) + 24;
trigger_error("Index name '{$table_name}_$index_name' on table '$table_name' is too long. The maximum is $max_length characters.", E_USER_ERROR);
}

switch ($this->sql_layer)
{
case 'postgres':
case 'oracle':
case 'sqlite':
case 'sqlite3':
$statements[] = 'CREATE UNIQUE INDEX ' . $table_name . '_' . $index_name . ' ON ' . $table_name . '(' . implode(', ', $column) . ')';
break;

case 'mysql_40':
case 'mysql_41':
$statements[] = 'ALTER TABLE ' . $table_name . ' ADD UNIQUE INDEX ' . $index_name . '(' . implode(', ', $column) . ')';
break;

case 'mssql':
case 'mssqlnative':
$statements[] = 'CREATE UNIQUE INDEX [' . $index_name . '] ON [' . $table_name . ']([' . implode('], [', $column) . '])';
break;
}

return $this->_sql_run_sql($statements);
}

/**
* Add index
*/
function sql_create_index($table_name, $index_name, $column)
{
$statements = array();

$table_prefix = substr(CONFIG_TABLE, 0, -6); // strlen(config)
if (strlen($table_name . $index_name) - strlen($table_prefix) > 24)
{
$max_length = strlen($table_prefix) + 24;
trigger_error("Index name '{$table_name}_$index_name' on table '$table_name' is too long. The maximum is $max_length characters.", E_USER_ERROR);
}

// remove index length unless MySQL4
if ('mysql_40' != $this->sql_layer)
{
$column = preg_replace('#:.*$#', '', $column);
}

switch ($this->sql_layer)
{
case 'postgres':
case 'oracle':
case 'sqlite':
case 'sqlite3':
$statements[] = 'CREATE INDEX ' . $table_name . '_' . $index_name . ' ON ' . $table_name . '(' . implode(', ', $column) . ')';
break;

case 'mysql_40':
// add index size to definition as required by MySQL4
foreach ($column as $i => $col)
{
if (false !== strpos($col, ':'))
{
list($col, $index_size) = explode(':', $col);
$column[$i] = "$col($index_size)";
}
}
// no break
case 'mysql_41':
$statements[] = 'ALTER TABLE ' . $table_name . ' ADD INDEX ' . $index_name . '(' . implode(', ', $column) . ')';
break;

case 'mssql':
case 'mssqlnative':
$statements[] = 'CREATE INDEX [' . $index_name . '] ON [' . $table_name . ']([' . implode('], [', $column) . '])';
break;
}

return $this->_sql_run_sql($statements);
}

/**
* List all of the indices that belong to a table,
* does not count:
* * UNIQUE indices
* * PRIMARY keys
*/
function sql_list_index($table_name)
{
$index_array = array();

if ($this->sql_layer == 'mssql' || $this->sql_layer == 'mssqlnative')
{
$sql = "EXEC sp_statistics '$table_name'";
$result = $this->db->sql_query($sql);
while ($row = $this->db->sql_fetchrow($result))
{
if ($row['TYPE'] == 3)
{
$index_array[] = $row['INDEX_NAME'];
}
}
$this->db->sql_freeresult($result);
}
else
{
switch ($this->sql_layer)
{
case 'postgres':
$sql = "SELECT ic.relname as index_name
FROM pg_class bc, pg_class ic, pg_index i
WHERE (bc.oid = i.indrelid)
AND (ic.oid = i.indexrelid)
AND (bc.relname = '" . $table_name . "')
AND (i.indisunique != 't')
AND (i.indisprimary != 't')";
$col = 'index_name';
break;

case 'mysql_40':
case 'mysql_41':
$sql = 'SHOW KEYS
FROM ' . $table_name;
$col = 'Key_name';
break;

case 'oracle':
$sql = "SELECT index_name
FROM user_indexes
WHERE table_name = '" . strtoupper($table_name) . "'
AND generated = 'N'
AND uniqueness = 'NONUNIQUE'";
$col = 'index_name';
break;

case 'sqlite':
case 'sqlite3':
$sql = "PRAGMA index_info('" . $table_name . "');";
$col = 'name';
break;
}

$result = $this->db->sql_query($sql);
while ($row = $this->db->sql_fetchrow($result))
{
if (($this->sql_layer == 'mysql_40' || $this->sql_layer == 'mysql_41') && !$row['Non_unique'])
{
continue;
}

switch ($this->sql_layer)
{
case 'oracle':
case 'postgres':
case 'sqlite':
case 'sqlite3':
$row[$col] = substr($row[$col], strlen($table_name) + 1);
break;
}

$index_array[] = $row[$col];
}
$this->db->sql_freeresult($result);
}

return array_map('strtolower', $index_array);
}

/**
* Removes table_name from the index_name if it is at the beginning
*
* @param $table_name
* @param $index_name
* @return string
*/
protected function strip_table_name_from_index_name($table_name, $index_name)
{
return (strpos(strtoupper($index_name), strtoupper($table_name)) === 0) ? substr($index_name, strlen($table_name) + 1) : $index_name;
}

/**
* Change column type (not name!)
*/
function sql_column_change($table_name, $column_name, $column_data, $inline = false)
{
$original_column_data = $column_data;
$column_data = $this->sql_prepare_column_data($table_name, $column_name, $column_data);
$statements = array();

switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
// We need the data here
$old_return_statements = $this->return_statements;
$this->return_statements = true;

$indexes = $this->get_existing_indexes($table_name, $column_name);
$unique_indexes = $this->get_existing_indexes($table_name, $column_name, true);

// Drop any indexes
if (!empty($indexes) || !empty($unique_indexes))
{
$drop_indexes = array_merge(array_keys($indexes), array_keys($unique_indexes));
foreach ($drop_indexes as $index_name)
{
$result = $this->sql_index_drop($table_name, $index_name);
$statements = array_merge($statements, $result);
}
}

// Drop default value constraint
$result = $this->mssql_get_drop_default_constraints_queries($table_name, $column_name);
$statements = array_merge($statements, $result);

// Change the column
$statements[] = 'ALTER TABLE [' . $table_name . '] ALTER COLUMN [' . $column_name . '] ' . $column_data['column_type_sql'];

if (!empty($column_data['default']))
{
// Add new default value constraint
$statements[] = 'ALTER TABLE [' . $table_name . '] ADD CONSTRAINT [DF_' . $table_name . '_' . $column_name . '_1] ' . $this->db->sql_escape($column_data['default']) . ' FOR [' . $column_name . ']';
}

if (!empty($indexes))
{
// Recreate indexes after we changed the column
foreach ($indexes as $index_name => $index_data)
{
$result = $this->sql_create_index($table_name, $index_name, $index_data);
$statements = array_merge($statements, $result);
}
}

if (!empty($unique_indexes))
{
// Recreate unique indexes after we changed the column
foreach ($unique_indexes as $index_name => $index_data)
{
$result = $this->sql_create_unique_index($table_name, $index_name, $index_data);
$statements = array_merge($statements, $result);
}
}

$this->return_statements = $old_return_statements;
break;

case 'mysql_40':
case 'mysql_41':
$statements[] = 'ALTER TABLE `' . $table_name . '` CHANGE `' . $column_name . '` `' . $column_name . '` ' . $column_data['column_type_sql'];
break;

case 'oracle':
// We need the data here
$old_return_statements = $this->return_statements;
$this->return_statements = true;

// Get list of existing indexes
$indexes = $this->get_existing_indexes($table_name, $column_name);
$unique_indexes = $this->get_existing_indexes($table_name, $column_name, true);

// Drop any indexes
if (!empty($indexes) || !empty($unique_indexes))
{
$drop_indexes = array_merge(array_keys($indexes), array_keys($unique_indexes));
foreach ($drop_indexes as $index_name)
{
$result = $this->sql_index_drop($table_name, $this->strip_table_name_from_index_name($table_name, $index_name));
$statements = array_merge($statements, $result);
}
}

$temp_column_name = 'temp_' . substr(md5($column_name), 0, 25);
// Add a temporary table with the new type
$result = $this->sql_column_add($table_name, $temp_column_name, $original_column_data);
$statements = array_merge($statements, $result);

// Copy the data to the new column
$statements[] = 'UPDATE ' . $table_name . ' SET ' . $temp_column_name . ' = ' . $column_name;

// Drop the original column
$result = $this->sql_column_remove($table_name, $column_name);
$statements = array_merge($statements, $result);

// Recreate the original column with the new type
$result = $this->sql_column_add($table_name, $column_name, $original_column_data);
$statements = array_merge($statements, $result);

if (!empty($indexes))
{
// Recreate indexes after we changed the column
foreach ($indexes as $index_name => $index_data)
{
$result = $this->sql_create_index($table_name, $this->strip_table_name_from_index_name($table_name, $index_name), $index_data);
$statements = array_merge($statements, $result);
}
}

if (!empty($unique_indexes))
{
// Recreate unique indexes after we changed the column
foreach ($unique_indexes as $index_name => $index_data)
{
$result = $this->sql_create_unique_index($table_name, $this->strip_table_name_from_index_name($table_name, $index_name), $index_data);
$statements = array_merge($statements, $result);
}
}

// Copy the data to the original column
$statements[] = 'UPDATE ' . $table_name . ' SET ' . $column_name . ' = ' . $temp_column_name;

// Drop the temporary column again
$result = $this->sql_column_remove($table_name, $temp_column_name);
$statements = array_merge($statements, $result);

$this->return_statements = $old_return_statements;
break;

case 'postgres':
$sql = 'ALTER TABLE ' . $table_name . ' ';

$sql_array = array();
$sql_array[] = 'ALTER COLUMN ' . $column_name . ' TYPE ' . $column_data['column_type'];

if (isset($column_data['null']))
{
if ($column_data['null'] == 'NOT NULL')
{
$sql_array[] = 'ALTER COLUMN ' . $column_name . ' SET NOT NULL';
}
else if ($column_data['null'] == 'NULL')
{
$sql_array[] = 'ALTER COLUMN ' . $column_name . ' DROP NOT NULL';
}
}

if (isset($column_data['default']))
{
$sql_array[] = 'ALTER COLUMN ' . $column_name . ' SET DEFAULT ' . $column_data['default'];
}

// we don't want to double up on constraints if we change different number data types
if (isset($column_data['constraint']))
{
$constraint_sql = "SELECT consrc as constraint_data
FROM pg_constraint, pg_class bc
WHERE conrelid = bc.oid
AND bc.relname = '{$table_name}'
AND NOT EXISTS (
SELECT *
FROM pg_constraint as c, pg_inherits as i
WHERE i.inhrelid = pg_constraint.conrelid
AND c.conname = pg_constraint.conname
AND c.consrc = pg_constraint.consrc
AND c.conrelid = i.inhparent
)";

$constraint_exists = false;

$result = $this->db->sql_query($constraint_sql);
while ($row = $this->db->sql_fetchrow($result))
{
if (trim($row['constraint_data']) == trim($column_data['constraint']))
{
$constraint_exists = true;
break;
}
}
$this->db->sql_freeresult($result);

if (!$constraint_exists)
{
$sql_array[] = 'ADD ' . $column_data['constraint'];
}
}

$sql .= implode(', ', $sql_array);

$statements[] = $sql;
break;

case 'sqlite':
case 'sqlite3':

if ($inline && $this->return_statements)
{
return $column_name . ' ' . $column_data['column_type_sql'];
}

$recreate_queries = $this->sqlite_get_recreate_table_queries($table_name);
if (empty($recreate_queries))
{
break;
}

$statements[] = 'begin';

$sql_create_table = array_shift($recreate_queries);

// Create a temp table and populate it, destroy the existing one
$statements[] = preg_replace('#CREATE\s+TABLE\s+"?' . $table_name . '"?#i', 'CREATE TEMPORARY TABLE ' . $table_name . '_temp', $sql_create_table);
$statements[] = 'INSERT INTO ' . $table_name . '_temp SELECT * FROM ' . $table_name;
$statements[] = 'DROP TABLE ' . $table_name;

preg_match('#\((.*)\)#s', $sql_create_table, $matches);

$new_table_cols = trim($matches[1]);
$old_table_cols = preg_split('/,(?![\s\w]+\))/m', $new_table_cols);
$column_list = array();

foreach ($old_table_cols as $key => $declaration)
{
$declaration = trim($declaration);

// Check for the beginning of the constraint section and stop
if (preg_match('/[^\(]*\s*PRIMARY KEY\s+\(/', $declaration) ||
preg_match('/[^\(]*\s*UNIQUE\s+\(/', $declaration) ||
preg_match('/[^\(]*\s*FOREIGN KEY\s+\(/', $declaration) ||
preg_match('/[^\(]*\s*CHECK\s+\(/', $declaration))
{
break;
}

$entities = preg_split('#\s+#', $declaration);
$column_list[] = $entities[0];
if ($entities[0] == $column_name)
{
$old_table_cols[$key] = $column_name . ' ' . $column_data['column_type_sql'];
}
}

$columns = implode(',', $column_list);

// Create a new table and fill it up. destroy the temp one
$statements[] = 'CREATE TABLE ' . $table_name . ' (' . implode(',', $old_table_cols) . ');';
$statements = array_merge($statements, $recreate_queries);

$statements[] = 'INSERT INTO ' . $table_name . ' (' . $columns . ') SELECT ' . $columns . ' FROM ' . $table_name . '_temp;';
$statements[] = 'DROP TABLE ' . $table_name . '_temp';

$statements[] = 'commit';

break;
}

return $this->_sql_run_sql($statements);
}

/**
* Get queries to drop the default constraints of a column
*
* We need to drop the default constraints of a column,
* before being able to change their type or deleting them.
*
* @param string $table_name
* @param string $column_name
* @return array Array with SQL statements
*/
protected function mssql_get_drop_default_constraints_queries($table_name, $column_name)
{
$statements = array();
if ($this->mssql_is_sql_server_2000())
{
// http://msdn.microsoft.com/en-us/library/aa175912%28v=sql.80%29.aspx
// Deprecated in SQL Server 2005
$sql = "SELECT so.name AS def_name
FROM sysobjects so
JOIN sysconstraints sc ON so.id = sc.constid
WHERE object_name(so.parent_obj) = '{$table_name}'
AND so.xtype = 'D'
AND sc.colid = (SELECT colid FROM syscolumns
WHERE id = object_id('{$table_name}')
AND name = '{$column_name}')";
}
else
{
$sql = "SELECT dobj.name AS def_name
FROM sys.columns col
LEFT OUTER JOIN sys.objects dobj ON (dobj.object_id = col.default_object_id AND dobj.type = 'D')
WHERE col.object_id = object_id('{$table_name}')
AND col.name = '{$column_name}'
AND dobj.name IS NOT NULL";
}

$result = $this->db->sql_query($sql);
while ($row = $this->db->sql_fetchrow($result))
{
$statements[] = 'ALTER TABLE [' . $table_name . '] DROP CONSTRAINT [' . $row['def_name'] . ']';
}
$this->db->sql_freeresult($result);

return $statements;
}

/**
* Get a list with existing indexes for the column
*
* @param string $table_name
* @param string $column_name
* @param bool $unique Should we get unique indexes or normal ones
* @return array Array with Index name => columns
*/
public function get_existing_indexes($table_name, $column_name, $unique = false)
{
switch ($this->sql_layer)
{
case 'mysql_40':
case 'mysql_41':
case 'postgres':
case 'sqlite':
case 'sqlite3':
// Not supported
throw new \Exception('DBMS is not supported');
break;
}

$sql = '';
$existing_indexes = array();

switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
if ($this->mssql_is_sql_server_2000())
{
// http://msdn.microsoft.com/en-us/library/aa175912%28v=sql.80%29.aspx
// Deprecated in SQL Server 2005
$sql = "SELECT DISTINCT ix.name AS phpbb_index_name
FROM sysindexes ix
INNER JOIN sysindexkeys ixc
ON ixc.id = ix.id
AND ixc.indid = ix.indid
INNER JOIN syscolumns cols
ON cols.colid = ixc.colid
AND cols.id = ix.id
WHERE ix.id = object_id('{$table_name}')
AND cols.name = '{$column_name}'
AND INDEXPROPERTY(ix.id, ix.name, 'IsUnique') = " . ($unique) ? '1' : '0';
}
else
{
$sql = "SELECT DISTINCT ix.name AS phpbb_index_name
FROM sys.indexes ix
INNER JOIN sys.index_columns ixc
ON ixc.object_id = ix.object_id
AND ixc.index_id = ix.index_id
INNER JOIN sys.columns cols
ON cols.column_id = ixc.column_id
AND cols.object_id = ix.object_id
WHERE ix.object_id = object_id('{$table_name}')
AND cols.name = '{$column_name}'
AND ix.is_unique = " . ($unique) ? '1' : '0';
}
break;

case 'oracle':
$sql = "SELECT ix.index_name AS phpbb_index_name, ix.uniqueness AS is_unique
FROM all_ind_columns ixc, all_indexes ix
WHERE ix.index_name = ixc.index_name
AND ixc.table_name = '" . strtoupper($table_name) . "'
AND ixc.column_name = '" . strtoupper($column_name) . "'";
break;
}

$result = $this->db->sql_query($sql);
while ($row = $this->db->sql_fetchrow($result))
{
if (!isset($row['is_unique']) || ($unique && $row['is_unique'] == 'UNIQUE') || (!$unique && $row['is_unique'] == 'NONUNIQUE'))
{
$existing_indexes[$row['phpbb_index_name']] = array();
}
}
$this->db->sql_freeresult($result);

if (empty($existing_indexes))
{
return array();
}

switch ($this->sql_layer)
{
case 'mssql':
case 'mssqlnative':
if ($this->mssql_is_sql_server_2000())
{
$sql = "SELECT DISTINCT ix.name AS phpbb_index_name, cols.name AS phpbb_column_name
FROM sysindexes ix
INNER JOIN sysindexkeys ixc
ON ixc.id = ix.id
AND ixc.indid = ix.indid
INNER JOIN syscolumns cols
ON cols.colid = ixc.colid
AND cols.id = ix.id
WHERE ix.id = object_id('{$table_name}')
AND " . $this->db->sql_in_set('ix.name', array_keys($existing_indexes));
}
else
{
$sql = "SELECT DISTINCT ix.name AS phpbb_index_name, cols.name AS phpbb_column_name
FROM sys.indexes ix
INNER JOIN sys.index_columns ixc
ON ixc.object_id = ix.object_id
AND ixc.index_id = ix.index_id
INNER JOIN sys.columns cols
ON cols.column_id = ixc.column_id
AND cols.object_id = ix.object_id
WHERE ix.object_id = object_id('{$table_name}')
AND " . $this->db->sql_in_set('ix.name', array_keys($existing_indexes));
}
break;

case 'oracle':
$sql = "SELECT index_name AS phpbb_index_name, column_name AS phpbb_column_name
FROM all_ind_columns
WHERE table_name = '" . strtoupper($table_name) . "'
AND " . $this->db->sql_in_set('index_name', array_keys($existing_indexes));
break;
}

$result = $this->db->sql_query($sql);
while ($row = $this->db->sql_fetchrow($result))
{
$existing_indexes[$row['phpbb_index_name']][] = $row['phpbb_column_name'];
}
$this->db->sql_freeresult($result);

return $existing_indexes;
}

/**
* Is the used MS SQL Server a SQL Server 2000?
*
* @return bool
*/
protected function mssql_is_sql_server_2000()
{
if ($this->is_sql_server_2000 === null)
{
$sql = "SELECT CAST(SERVERPROPERTY('productversion') AS VARCHAR(25)) AS mssql_version";
$result = $this->db->sql_query($sql);
$properties = $this->db->sql_fetchrow($result);
$this->db->sql_freeresult($result);
$this->is_sql_server_2000 = $properties['mssql_version'][0] == '8';
}

return $this->is_sql_server_2000;
}

/**
* Returns the Queries which are required to recreate a table including indexes
*
* @param string $table_name
* @param string $remove_column When we drop a column, we remove the column
* from all indexes. If the index has no other
* column, we drop it completly.
* @return array
*/
protected function sqlite_get_recreate_table_queries($table_name, $remove_column = '')
{
$queries = array();

$sql = "SELECT sql
FROM sqlite_master
WHERE type = 'table'
AND name = '{$table_name}'";
$result = $this->db->sql_query($sql);
$sql_create_table = $this->db->sql_fetchfield('sql');
$this->db->sql_freeresult($result);

if (!$sql_create_table)
{
return array();
}
$queries[] = $sql_create_table;

$sql = "SELECT sql
FROM sqlite_master
WHERE type = 'index'
AND tbl_name = '{$table_name}'";
$result = $this->db->sql_query($sql);
while ($sql_create_index = $this->db->sql_fetchfield('sql'))
{
if ($remove_column)
{
$match = array();
preg_match('#(?:[\w ]+)\((.*)\)#', $sql_create_index, $match);
if (!isset($match[1]))
{
continue;
}

// Find and remove $remove_column from the index
$columns = explode(', ', $match[1]);
$found_column = array_search($remove_column, $columns);
if ($found_column !== false)
{
unset($columns[$found_column]);

// If the column list is not empty add the index to the list
if (!empty($columns))
{
$queries[] = str_replace($match[1], implode(', ', $columns), $sql_create_index);
}
}
else
{
$queries[] = $sql_create_index;
}
}
else
{
$queries[] = $sql_create_index;
}
}
$this->db->sql_freeresult($result);

return $queries;
}
}