maybe_convert_table_to_utf8mb4

If a table only contains utf8 or utf8mb4 columns, convert it to utf8mb4.

Description

maybe_convert_table_to_utf8mb4( (string) $table ); 

Parameters (1)

0. $table (string)
The table to convert.

Usage

  1. if ( !function_exists( 'maybe_convert_table_to_utf8mb4' ) ) { 
  2.     require_once ABSPATH . '/wp-admin/includes/upgrade.php'; 
  3. } 
  4.   
  5. // The table to convert. 
  6. $table = ''; 
  7.   
  8. // NOTICE! Understand what this does before running. 
  9. $result = maybe_convert_table_to_utf8mb4($table); 
  10.     

Defined (1)

The function is defined in the following location(s).

/wp-admin/includes/upgrade.php  
  1. function maybe_convert_table_to_utf8mb4( $table ) { 
  2.     global $wpdb; 
  3.  
  4.     $results = $wpdb->get_results( "SHOW FULL COLUMNS FROM `$table`" ); 
  5.     if ( ! $results ) { 
  6.         return false; 
  7.     } 
  8.  
  9.     foreach ( $results as $column ) { 
  10.         if ( $column->Collation ) { 
  11.             list( $charset ) = explode( '_', $column->Collation ); 
  12.             $charset = strtolower( $charset ); 
  13.             if ( 'utf8' !== $charset && 'utf8mb4' !== $charset ) { 
  14.                 // Don't upgrade tables that have non-utf8 columns. 
  15.                 return false; 
  16.             } 
  17.         } 
  18.     } 
  19.  
  20.     $table_details = $wpdb->get_row( "SHOW TABLE STATUS LIKE '$table'" ); 
  21.     if ( ! $table_details ) { 
  22.         return false; 
  23.     } 
  24.  
  25.     list( $table_charset ) = explode( '_', $table_details->Collation ); 
  26.     $table_charset = strtolower( $table_charset ); 
  27.     if ( 'utf8mb4' === $table_charset ) { 
  28.         return true; 
  29.     } 
  30.  
  31.     return $wpdb->query( "ALTER TABLE $table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci" ); 
  32. }