public function DatabaseSchema_mysql::addUniqueKey

Add a unique key.

Parameters

string $table: The table to be altered.

string $name: The name of the key.

string[] $fields: An array of field names.

Return value

void:

Throws

DatabaseSchemaObjectDoesNotExistException If the specified table doesn't exist.

DatabaseSchemaObjectExistsException If the specified table already has a key by that name.

Overrides DatabaseSchema::addUniqueKey

File

core/includes/database/mysql/schema.inc, line 477

Database schema code for MySQL database servers.

Class

DatabaseSchema_mysql

Class to create and manipulate MySQL tables.

Code

public function addUniqueKey($table, $name, $fields) {
  if (!$this->tableExists($table)) {
    throw new DatabaseSchemaObjectDoesNotExistException(t("Cannot add unique key @name to table @table: table doesn't exist.", array(
      '@table' => $table,
      '@name' => $name,
    )));
  }
  if ($this->indexExists($table, $name)) {
    throw new DatabaseSchemaObjectExistsException(t("Cannot add unique key @name to table @table: unique key already exists.", array(
      '@table' => $table,
      '@name' => $name,
    )));
  }

  $this->connection->query('ALTER TABLE {' . $table . '} ADD UNIQUE KEY `' . $name . '` (' . $this->createKeySql($fields) . ')');
}