5.4.4 mysql_change_user()

bool
mysql_change_user(MYSQL *mysql,
                  const char *user,
                  const char *password,
                  const char *db)

Description

Changes the user and causes the database specified by db to become the default (current) database on the connection specified by mysql. In subsequent queries, this database is the default for table references that include no explicit database specifier.

mysql_change_user() fails if the connected user cannot be authenticated or does not have permission to use the database. In this case, the user and database are not changed.

Pass a db parameter of NULL if you do not want to have a default database.

This function resets the session state as if one had done a new connect and reauthenticated. (See Section 3.6.8, “Automatic Reconnection Control”.) It always performs a ROLLBACK of any active transactions, closes and drops all temporary tables, and unlocks all locked tables. It resets session system variables to the values of the corresponding global system variables, releases prepared statements, closes HANDLER variables, and releases locks acquired with GET_LOCK(). Clears any current query attributes defined as a result of calling mysql_bind_param(). These effects occur even if the user did not change.

To reset the connection state in a more lightweight manner without changing the user, use mysql_reset_connection().

Return Values

Zero for success. Nonzero if an error occurred.

Errors

The same that you can get from mysql_real_connect(), plus:

• CR_COMMANDS_OUT_OF_SYNC

  Commands were executed in an improper order.

• CR_SERVER_GONE_ERROR

  The MySQL server has gone away.

• CR_SERVER_LOST

  The connection to the server was lost during the query.

• CR_UNKNOWN_ERROR

  An unknown error occurred.

• ER_UNKNOWN_COM_ERROR

  The MySQL server does not implement this command (probably an old server).

• ER_ACCESS_DENIED_ERROR

  The user or password was wrong.

• ER_BAD_DB_ERROR

  The database did not exist.

• ER_DBACCESS_DENIED_ERROR

  The user did not have access rights to the database.

• ER_WRONG_DB_NAME

  The database name was too long.

Example

if (mysql_change_user(&mysql, "user", "password", "new_database"))
{
   fprintf(stderr, "Failed to change user.  Error: %s\n",
           mysql_error(&mysql));
}