Question

maybe_drop_column( string $table_name,  string $column_name,  string $drop_ddl )

Drop column from database table, if it exists.

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description

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参数

$table_name

(string) (Required) Table name

$column_name

(string) (Required) Column name

$drop_ddl

(string) (Required) SQL statement to drop column.

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返回值

(bool) False on failure, true on success or doesn't exist.

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源代码

File: wp-admin/install-helper.php

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;
}

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更新日志

Version	description
1.0.0	Introduced.

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相关函数

Uses

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

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User Contributed Notes