Viewing file:  install-helper.php (5.93 KB) -rw-rw-r--
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<?php
/**
* Plugins may load this file to gain access to special helper functions for
* plugin installation. This file is not included by WordPress and it is
* recommended, to prevent fatal errors, that this file is included using
* require_once.
*
* These functions are not optimized for speed, but they should only be used
* once in a while, so speed shouldn't be a concern. If it is and you are
* needing to use these functions a lot, you might experience time outs. If you
* do, then it is advised to just write the SQL code yourself.
*
* check_column( 'wp_links', 'link_description', 'mediumtext' );
* if ( check_column( $wpdb->comments, 'comment_author', 'tinytext' ) ) {
* echo "ok\n";
* }
*
* $error_count = 0;
* $tablename = $wpdb->links;
* // Check the column.
* if ( ! check_column( $wpdb->links, 'link_description', 'varchar( 255 )' ) ) {
* $ddl = "ALTER TABLE $wpdb->links MODIFY COLUMN link_description varchar(255) NOT NULL DEFAULT '' ";
* $q = $wpdb->query( $ddl );
* }
*
* if ( check_column( $wpdb->links, 'link_description', 'varchar( 255 )' ) ) {
* $res .= $tablename . ' - ok <br />';
* } else {
* $res .= 'There was a problem with ' . $tablename . '<br />';
* ++$error_count;
* }
*
* @package WordPress
* @subpackage Plugin
*/
/** Load WordPress Bootstrap */
require_once dirname( __DIR__ ) . '/wp-load.php';
if ( ! function_exists( 'maybe_create_table' ) ) :
/**
* Creates a table in the database if it doesn't already exist.
*
* @since 1.0.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param string $table_name Database table name.
* @param string $create_ddl SQL statement to create table.
* @return bool True on success or if the table already exists. False on failure.
*/
function maybe_create_table( $table_name, $create_ddl ) {
global $wpdb;
foreach ( $wpdb->get_col( 'SHOW TABLES', 0 ) as $table ) {
if ( $table === $table_name ) {
return true;
}
}
// Didn't find it, so try to create it.
$wpdb->query( $create_ddl );
// We cannot directly tell that whether this succeeded!
foreach ( $wpdb->get_col( 'SHOW TABLES', 0 ) as $table ) {
if ( $table === $table_name ) {
return true;
}
}
return false;
}
endif;
if ( ! function_exists( 'maybe_add_column' ) ) :
/**
* Adds column to database table, if it doesn't already exist.
*
* @since 1.0.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param string $table_name Database table name.
* @param string $column_name Table column name.
* @param string $create_ddl SQL statement to add column.
* @return bool True on success or if the column already exists. False on failure.
*/
function maybe_add_column( $table_name, $column_name, $create_ddl ) {
global $wpdb;
foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {
if ( $column === $column_name ) {
return true;
}
}
// Didn't find it, so try to create it.
$wpdb->query( $create_ddl );
// We cannot directly tell that whether this succeeded!
foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {
if ( $column === $column_name ) {
return true;
}
}
return false;
}
endif;
/**
* Drops column from database table, if it exists.
*
* @since 1.0.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param string $table_name Database table name.
* @param string $column_name Table column name.
* @param string $drop_ddl SQL statement to drop column.
* @return bool True on success or if the column doesn't exist. False on failure.
*/
function maybe_drop_column( $table_name, $column_name, $drop_ddl ) {
global $wpdb;
foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {
if ( $column === $column_name ) {
// Found it, so try to drop it.
$wpdb->query( $drop_ddl );
// We cannot directly tell that whether this succeeded!
foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {
if ( $column === $column_name ) {
return false;
}
}
}
}
// Else didn't find it.
return true;
}
/**
* Checks that database table column matches the criteria.
*
* Uses the SQL DESC for retrieving the table info for the column. It will help
* understand the parameters, if you do more research on what column information
* is returned by the SQL statement. Pass in null to skip checking that
* criteria.
*
* Column names returned from DESC table are case sensitive and are listed:
* Field
* Type
* Null
* Key
* Default
* Extra
*
* @since 1.0.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @param string $table_name Database table name.
* @param string $col_name Table column name.
* @param string $col_type Table column type.
* @param bool $is_null Optional. Check is null.
* @param mixed $key Optional. Key info.
* @param mixed $default_value Optional. Default value.
* @param mixed $extra Optional. Extra value.
* @return bool True, if matches. False, if not matching.
*/
function check_column( $table_name, $col_name, $col_type, $is_null = null, $key = null, $default_value = null, $extra = null ) {
global $wpdb;
$diffs = 0;
$results = $wpdb->get_results( "DESC $table_name" );
foreach ( $results as $row ) {
if ( $row->Field === $col_name ) {
// Got our column, check the params.
if ( ( null !== $col_type ) && ( $row->Type !== $col_type ) ) {
++$diffs;
}
if ( ( null !== $is_null ) && ( $row->Null !== $is_null ) ) {
++$diffs;
}
if ( ( null !== $key ) && ( $row->Key !== $key ) ) {
++$diffs;
}
if ( ( null !== $default_value ) && ( $row->Default !== $default_value ) ) {
++$diffs;
}
if ( ( null !== $extra ) && ( $row->Extra !== $extra ) ) {
++$diffs;
}
if ( $diffs > 0 ) {
return false;
}
return true;
} // End if found our column.
}
return false;
}
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