Question

maybe_convert_table_to_utf8mb4( string $table )

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

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description

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参数

$table

(string) (Required) The table to convert.

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返回值

(bool) true if the table was converted, false if it wasn't.

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源代码

File: wp-admin/includes/upgrade.php

function maybe_convert_table_to_utf8mb4( $table ) {
	global $wpdb;

	$results = $wpdb->get_results( "SHOW FULL COLUMNS FROM `$table`" );
	if ( ! $results ) {
		return false;
	}

	foreach ( $results as $column ) {
		if ( $column->Collation ) {
			list( $charset ) = explode( '_', $column->Collation );
			$charset = strtolower( $charset );
			if ( 'utf8' !== $charset && 'utf8mb4' !== $charset ) {
				// Don't upgrade tables that have non-utf8 columns.
				return false;
			}
		}
	}

	$table_details = $wpdb->get_row( "SHOW TABLE STATUS LIKE '$table'" );
	if ( ! $table_details ) {
		return false;
	}

	list( $table_charset ) = explode( '_', $table_details->Collation );
	$table_charset = strtolower( $table_charset );
	if ( 'utf8mb4' === $table_charset ) {
		return true;
	}

	return $wpdb->query( "ALTER TABLE $table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci" );
}

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更新日志

Version	description
4.2.0	Introduced.

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相关函数

Uses

• wp-includes/wp-db.php: wpdb::get_results()
• wp-includes/wp-db.php: wpdb::get_row()
• wp-includes/wp-db.php: wpdb::query()

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Used By

• wp-admin/includes/upgrade.php: pre_schema_upgrade()
• wp-admin/includes/upgrade.php: upgrade_network()

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User Contributed Notes