session_start(++Login, ++Password, ++Options, -Session)

Login

DBMS login: ID or ID@Host. (ID,Host: string or atom)

Password

Password (string or atom)

Options

Options (list or nil)

Session

Session handle

Description

Starts a new session with the DBMS. A new connection with the DBMS server is established, with the supplied DBMS user ID. Optionally, a host could be supplied, if the server is located on a remote machine. The host could be either the machine name, or an IP address. A session handle for this new connection is returned by the predicate.

The session is closed automatically if the program backtracks or aborts back beyond this call.

Options is a (possibly empty) list of Option:Value pairs, specifying any options for this session. The following options are supported:

dbname

Specifies the name of the database to use. Value can be a string or an atom. The same effect can also be achieved by issuing the SQL statement USE ... (where ... is the dbname).

storage

(MySQL specific) specifies the default storage model to use for the tables. Value can be either the string/atom transactional or non-transactional. For transactional tables, changes are local until they are committed. Uncommitted changes can be rollback. For non-transactional tables, changes are global. InnoDB (with autocommit turned off) is the storage engine used for transactional, and MyISAM is the storage engine used for non-transactional. See the MySQL manual for details on storage engines and their effect on tables.

Exceptions

(5) type error

Login, Password or Options not of the correct type.

(6) out of range

Invalid option specification in Options.

(dbi_bad_field)

Problems with Option's argument.

(dbi_error)

Problems connecting to DBMS server.

Examples

     % connecting to a database server running on the local machine, as 
     % database user sqluser with password password
     session_start("sqluser", "password", [], S).

     % connecting to a database server running on machine my.sql.host,
     % as database user sqluser with password password, and selecting
     % to use the database mydb
     session_start(sqluser@my.sql.host, password, [dbame:"mydb"], S).

See Also