maybe_add_column
函数
maybe_add_column ( $table_name, $column_name, $create_ddl )
- 参数
-
-
(string)
$table_name
Database table name.- Required: 是
-
(string)
$column_name
Table column name.- Required: 是
-
(string)
$create_ddl
SQL statement to add column.- Required: 是
-
(string)
- 返回值
-
- (bool) True on success or if the column already exists. False on failure.
- 定义位置
-
-
wp-admin/install-helper.php
, line 88
-
wp-admin/install-helper.php
- 引入
- 1.0.0
- 弃用
- –
Adds column to database table, if it doesn’t already exist.
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. */
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