dbDelta( string[]|string $queries = '', bool $execute = true )
Modifies the database based on specified SQL statements.
Description
Useful for creating new tables and updating existing tables to a new structure.
Parameters
- $queries
-
(Optional) The query to run. Can be multiple queries in an array, or a string of queries separated by semicolons.
Default value: ''
- $execute
-
(Optional) Whether or not to execute the query right away.<br>
Default value: true
Return
(array) Strings containing the results of the various update queries.
Source
File: wp-admin/includes/upgrade.php
function dbDelta( $queries = '', $execute = true ) {
global $wpdb;
if ( in_array( $queries, array( '', 'all', 'blog', 'global', 'ms_global' ), true ) )
$queries = wp_get_db_schema( $queries );
// Separate individual queries into an array
if ( !is_array($queries) ) {
$queries = explode( ';', $queries );
$queries = array_filter( $queries );
}
/**
* Filters the dbDelta SQL queries.
*
* @since WP-3.3.0
*
* @param array $queries An array of dbDelta SQL queries.
*/
$queries = apply_filters( 'dbdelta_queries', $queries );
$cqueries = array(); // Creation Queries
$iqueries = array(); // Insertion Queries
$for_update = array();
// Create a tablename index for an array ($cqueries) of queries
foreach ($queries as $qry) {
if ( preg_match( "|CREATE TABLE ([^ ]*)|", $qry, $matches ) ) {
$cqueries[ trim( $matches[1], '`' ) ] = $qry;
$for_update[$matches[1]] = 'Created table '.$matches[1];
} elseif ( preg_match( "|CREATE DATABASE ([^ ]*)|", $qry, $matches ) ) {
array_unshift( $cqueries, $qry );
} elseif ( preg_match( "|INSERT INTO ([^ ]*)|", $qry, $matches ) ) {
$iqueries[] = $qry;
} elseif ( preg_match( "|UPDATE ([^ ]*)|", $qry, $matches ) ) {
$iqueries[] = $qry;
} else {
// Unrecognized query type
}
}
/**
* Filters the dbDelta SQL queries for creating tables and/or databases.
*
* Queries filterable via this hook contain "CREATE TABLE" or "CREATE DATABASE".
*
* @since WP-3.3.0
*
* @param array $cqueries An array of dbDelta create SQL queries.
*/
$cqueries = apply_filters( 'dbdelta_create_queries', $cqueries );
/**
* Filters the dbDelta SQL queries for inserting or updating.
*
* Queries filterable via this hook contain "INSERT INTO" or "UPDATE".
*
* @since WP-3.3.0
*
* @param array $iqueries An array of dbDelta insert or update SQL queries.
*/
$iqueries = apply_filters( 'dbdelta_insert_queries', $iqueries );
$text_fields = array( 'tinytext', 'text', 'mediumtext', 'longtext' );
$blob_fields = array( 'tinyblob', 'blob', 'mediumblob', 'longblob' );
$global_tables = $wpdb->tables( 'global' );
foreach ( $cqueries as $table => $qry ) {
// Upgrade global tables only for the main site. Don't upgrade at all if conditions are not optimal.
if ( in_array( $table, $global_tables ) && ! wp_should_upgrade_global_tables() ) {
unset( $cqueries[ $table ], $for_update[ $table ] );
continue;
}
// Fetch the table column structure from the database
$suppress = $wpdb->suppress_errors();
$tablefields = $wpdb->get_results("DESCRIBE {$table};");
$wpdb->suppress_errors( $suppress );
if ( ! $tablefields )
continue;
// Clear the field and index arrays.
$cfields = $indices = $indices_without_subparts = array();
// Get all of the field names in the query from between the parentheses.
preg_match("|\((.*)\)|ms", $qry, $match2);
$qryline = trim($match2[1]);
// Separate field lines into an array.
$flds = explode("\n", $qryline);
// For every field line specified in the query.
foreach ( $flds as $fld ) {
$fld = trim( $fld, " \t\n\r\0\x0B," ); // Default trim characters, plus ','.
// Extract the field name.
preg_match( '|^([^ ]*)|', $fld, $fvals );
$fieldname = trim( $fvals[1], '`' );
$fieldname_lowercased = strtolower( $fieldname );
// Verify the found field name.
$validfield = true;
switch ( $fieldname_lowercased ) {
case '':
case 'primary':
case 'index':
case 'fulltext':
case 'unique':
case 'key':
case 'spatial':
$validfield = false;
/*
* Normalize the index definition.
*
* This is done so the definition can be compared against the result of a
* `SHOW INDEX FROM $table_name` query which returns the current table
* index information.
*/
// Extract type, name and columns from the definition.
preg_match(
'/^'
. '(?P<index_type>' // 1) Type of the index.
. 'PRIMARY\s+KEY|(?:UNIQUE|FULLTEXT|SPATIAL)\s+(?:KEY|INDEX)|KEY|INDEX'
. ')'
. '\s+' // Followed by at least one white space character.
. '(?:' // Name of the index. Optional if type is PRIMARY KEY.
. '`?' // Name can be escaped with a backtick.
. '(?P<index_name>' // 2) Name of the index.
. '(?:[0-9a-zA-Z$_-]|[\xC2-\xDF][\x80-\xBF])+'
. ')'
. '`?' // Name can be escaped with a backtick.
. '\s+' // Followed by at least one white space character.
. ')*'
. '\(' // Opening bracket for the columns.
. '(?P<index_columns>'
. '.+?' // 3) Column names, index prefixes, and orders.
. ')'
. '\)' // Closing bracket for the columns.
. '$/im',
$fld,
$index_matches
);
// Uppercase the index type and normalize space characters.
$index_type = strtoupper( preg_replace( '/\s+/', ' ', trim( $index_matches['index_type'] ) ) );
// 'INDEX' is a synonym for 'KEY', standardize on 'KEY'.
$index_type = str_replace( 'INDEX', 'KEY', $index_type );
// Escape the index name with backticks. An index for a primary key has no name.
$index_name = ( 'PRIMARY KEY' === $index_type ) ? '' : '`' . strtolower( $index_matches['index_name'] ) . '`';
// Parse the columns. Multiple columns are separated by a comma.
$index_columns = $index_columns_without_subparts = array_map( 'trim', explode( ',', $index_matches['index_columns'] ) );
// Normalize columns.
foreach ( $index_columns as $id => &$index_column ) {
// Extract column name and number of indexed characters (sub_part).
preg_match(
'/'
. '`?' // Name can be escaped with a backtick.
. '(?P<column_name>' // 1) Name of the column.
. '(?:[0-9a-zA-Z$_-]|[\xC2-\xDF][\x80-\xBF])+'
. ')'
. '`?' // Name can be escaped with a backtick.
. '(?:' // Optional sub part.
. '\s*' // Optional white space character between name and opening bracket.
. '\(' // Opening bracket for the sub part.
. '\s*' // Optional white space character after opening bracket.
. '(?P<sub_part>'
. '\d+' // 2) Number of indexed characters.
. ')'
. '\s*' // Optional white space character before closing bracket.
. '\)' // Closing bracket for the sub part.
. ')?'
. '/',
$index_column,
$index_column_matches
);
// Escape the column name with backticks.
$index_column = '`' . $index_column_matches['column_name'] . '`';
// We don't need to add the subpart to $index_columns_without_subparts
$index_columns_without_subparts[ $id ] = $index_column;
// Append the optional sup part with the number of indexed characters.
if ( isset( $index_column_matches['sub_part'] ) ) {
$index_column .= '(' . $index_column_matches['sub_part'] . ')';
}
}
// Build the normalized index definition and add it to the list of indices.
$indices[] = "{$index_type} {$index_name} (" . implode( ',', $index_columns ) . ")";
$indices_without_subparts[] = "{$index_type} {$index_name} (" . implode( ',', $index_columns_without_subparts ) . ")";
// Destroy no longer needed variables.
unset( $index_column, $index_column_matches, $index_matches, $index_type, $index_name, $index_columns, $index_columns_without_subparts );
break;
}
// If it's a valid field, add it to the field array.
if ( $validfield ) {
$cfields[ $fieldname_lowercased ] = $fld;
}
}
// For every field in the table.
foreach ( $tablefields as $tablefield ) {
$tablefield_field_lowercased = strtolower( $tablefield->Field );
$tablefield_type_lowercased = strtolower( $tablefield->Type );
// If the table field exists in the field array ...
if ( array_key_exists( $tablefield_field_lowercased, $cfields ) ) {
// Get the field type from the query.
preg_match( '|`?' . $tablefield->Field . '`? ([^ ]*( unsigned)?)|i', $cfields[ $tablefield_field_lowercased ], $matches );
$fieldtype = $matches[1];
$fieldtype_lowercased = strtolower( $fieldtype );
// Is actual field type different from the field type in query?
if ($tablefield->Type != $fieldtype) {
$do_change = true;
if ( in_array( $fieldtype_lowercased, $text_fields ) && in_array( $tablefield_type_lowercased, $text_fields ) ) {
if ( array_search( $fieldtype_lowercased, $text_fields ) < array_search( $tablefield_type_lowercased, $text_fields ) ) {
$do_change = false;
}
}
if ( in_array( $fieldtype_lowercased, $blob_fields ) && in_array( $tablefield_type_lowercased, $blob_fields ) ) {
if ( array_search( $fieldtype_lowercased, $blob_fields ) < array_search( $tablefield_type_lowercased, $blob_fields ) ) {
$do_change = false;
}
}
if ( $do_change ) {
// Add a query to change the column type.
$cqueries[] = "ALTER TABLE {$table} CHANGE COLUMN `{$tablefield->Field}` " . $cfields[ $tablefield_field_lowercased ];
$for_update[$table.'.'.$tablefield->Field] = "Changed type of {$table}.{$tablefield->Field} from {$tablefield->Type} to {$fieldtype}";
}
}
// Get the default value from the array.
if ( preg_match( "| DEFAULT '(.*?)'|i", $cfields[ $tablefield_field_lowercased ], $matches ) ) {
$default_value = $matches[1];
if ($tablefield->Default != $default_value) {
// Add a query to change the column's default value
$cqueries[] = "ALTER TABLE {$table} ALTER COLUMN `{$tablefield->Field}` SET DEFAULT '{$default_value}'";
$for_update[$table.'.'.$tablefield->Field] = "Changed default value of {$table}.{$tablefield->Field} from {$tablefield->Default} to {$default_value}";
}
}
// Remove the field from the array (so it's not added).
unset( $cfields[ $tablefield_field_lowercased ] );
} else {
// This field exists in the table, but not in the creation queries?
}
}
// For every remaining field specified for the table.
foreach ($cfields as $fieldname => $fielddef) {
// Push a query line into $cqueries that adds the field to that table.
$cqueries[] = "ALTER TABLE {$table} ADD COLUMN $fielddef";
$for_update[$table.'.'.$fieldname] = 'Added column '.$table.'.'.$fieldname;
}
// Index stuff goes here. Fetch the table index structure from the database.
$tableindices = $wpdb->get_results("SHOW INDEX FROM {$table};");
if ($tableindices) {
// Clear the index array.
$index_ary = array();
// For every index in the table.
foreach ($tableindices as $tableindex) {
// Add the index to the index data array.
$keyname = strtolower( $tableindex->Key_name );
$index_ary[$keyname]['columns'][] = array('fieldname' => $tableindex->Column_name, 'subpart' => $tableindex->Sub_part);
$index_ary[$keyname]['unique'] = ($tableindex->Non_unique == 0)?true:false;
$index_ary[$keyname]['index_type'] = $tableindex->Index_type;
}
// For each actual index in the index array.
foreach ($index_ary as $index_name => $index_data) {
// Build a create string to compare to the query.
$index_string = '';
if ($index_name == 'primary') {
$index_string .= 'PRIMARY ';
} elseif ( $index_data['unique'] ) {
$index_string .= 'UNIQUE ';
}
if ( 'FULLTEXT' === strtoupper( $index_data['index_type'] ) ) {
$index_string .= 'FULLTEXT ';
}
if ( 'SPATIAL' === strtoupper( $index_data['index_type'] ) ) {
$index_string .= 'SPATIAL ';
}
$index_string .= 'KEY ';
if ( 'primary' !== $index_name ) {
$index_string .= '`' . $index_name . '`';
}
$index_columns = '';
// For each column in the index.
foreach ($index_data['columns'] as $column_data) {
if ( $index_columns != '' ) {
$index_columns .= ',';
}
// Add the field to the column list string.
$index_columns .= '`' . $column_data['fieldname'] . '`';
}
// Add the column list to the index create string.
$index_string .= " ($index_columns)";
// Check if the index definition exists, ignoring subparts.
if ( ! ( ( $aindex = array_search( $index_string, $indices_without_subparts ) ) === false ) ) {
// If the index already exists (even with different subparts), we don't need to create it.
unset( $indices_without_subparts[ $aindex ] );
unset( $indices[ $aindex ] );
}
}
}
// For every remaining index specified for the table.
foreach ( (array) $indices as $index ) {
// Push a query line into $cqueries that adds the index to that table.
$cqueries[] = "ALTER TABLE {$table} ADD $index";
$for_update[] = 'Added index ' . $table . ' ' . $index;
}
// Remove the original table creation query from processing.
unset( $cqueries[ $table ], $for_update[ $table ] );
}
$allqueries = array_merge($cqueries, $iqueries);
if ($execute) {
foreach ($allqueries as $query) {
$wpdb->query($query);
}
}
return $for_update;
}
Changelog
Version | Description |
---|---|
6.1.0 | Ignores display width for integer data types on MySQL 8.0.17 or later, to match MySQL behavior. Note: This does not affect MariaDB. |
1.5.0 | Introduced. |