wpdb::get_col_length( string $table, string $column )

Retrieve the maximum string length allowed in a given column.


Description Description

The length may either be specified as a byte length or a character length.


Parameters Parameters

$table

(string) (Required) Table name.

$column

(string) (Required) Column name.


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Return Return

(array|false|WP_Error) array( 'length' => (int), 'type' => 'byte' | 'char' ) false if the column has no length (for example, numeric column) WP_Error object if there was an error.


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Source Source

File: wp-includes/wp-db.php

	public function get_col_length( $table, $column ) {
		$tablekey = strtolower( $table );
		$columnkey = strtolower( $column );

		// Skip this entirely if this isn't a MySQL database.
		if ( empty( $this->is_mysql ) ) {
			return false;
		}

		if ( empty( $this->col_meta[ $tablekey ] ) ) {
			// This primes column information for us.
			$table_charset = $this->get_table_charset( $table );
			if ( is_wp_error( $table_charset ) ) {
				return $table_charset;
			}
		}

		if ( empty( $this->col_meta[ $tablekey ][ $columnkey ] ) ) {
			return false;
		}

		$typeinfo = explode( '(', $this->col_meta[ $tablekey ][ $columnkey ]->Type );

		$type = strtolower( $typeinfo[0] );
		if ( ! empty( $typeinfo[1] ) ) {
			$length = trim( $typeinfo[1], ')' );
		} else {
			$length = false;
		}

		switch( $type ) {
			case 'char':
			case 'varchar':
				return array(
					'type'   => 'char',
					'length' => (int) $length,
				);

			case 'binary':
			case 'varbinary':
				return array(
					'type'   => 'byte',
					'length' => (int) $length,
				);

			case 'tinyblob':
			case 'tinytext':
				return array(
					'type'   => 'byte',
					'length' => 255,        // 2^8 - 1
				);

			case 'blob':
			case 'text':
				return array(
					'type'   => 'byte',
					'length' => 65535,      // 2^16 - 1
				);

			case 'mediumblob':
			case 'mediumtext':
				return array(
					'type'   => 'byte',
					'length' => 16777215,   // 2^24 - 1
				);

			case 'longblob':
			case 'longtext':
				return array(
					'type'   => 'byte',
					'length' => 4294967295, // 2^32 - 1
				);

			default:
				return false;
		}
	}

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Changelog Changelog

Changelog
Version Description
4.2.1 Introduced.


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