Connection Strings

The connection string used for Z MySQL Database Connection objects are of the form:

[*lock_name][+|-]database[@host[:port]] [user [password [unix_socket]]]

or typically just:

database user password

to use a MySQL server on the local host via the standard UNIX socket.

The components are as follows:

  • *lock_name at the begining of the connection string leads to pseudo-transactional behavior. When the Zope transaction begins, a lock named after lock_name is acquired on the database server. When the Zope transaction commits, the database lock will be released. If the Zope transaction is aborted and restarted, which can happen due to ConflictErrors, you’ll get an error in the logs, and inconsistent data. In this respect, it’s equivalent to transactions turned off.

    Transactions are highly recommended. Using a named lock in conjunctions with transactions is probably pointless.

  • + or -: Integrate database transactions with the Zope transaction machinery. A - in front of the database tells ZMySQLDA to not use Zope’s Transaction Manager, even if the server supports transactions. A + in front of the database tells ZMySQLDA that it must use transactions; an exception will be raised if they are not supported by the server. If neither - or + are present, then transactions will be enabled if the server supports them. If you are using non-transaction safe tables (TSTs) on a server that supports TSTs, use -. If you require transactions, use +. If you aren’t sure, don’t use either.

  • database: The name of the database to connect to.

  • host/port: Host and port where the database server listens. Only use this if the database server is on a remote system. To use a non-standard port on the local system, use for the host instead of the hostname localhost.

  • user/password: Log into the database with the provided user and password.

  • unix_socket: If the UNIX socket is in a non-standard location, you can specify the full path to it after the password.