Sets the transaction locking and
isolation.
link_identifierA FrontBase link identifier returned by fbsql_connect() or fbsql_pconnect().
If optional and not specified, the function will try to find an open link to the FrontBase server and if no such link is found it will try to create one as if fbsql_connect() was called with no arguments
lockingThe type of locking to be set. It can be one of the following constants: FBSQL_LOCK_DEFERRED, FBSQL_LOCK_OPTIMISTIC, or FBSQL_LOCK_PESSIMISTIC.
isolationThe type of isolation to be set. It can be one of the following constants: FBSQL_ISO_READ_UNCOMMITTED, FBSQL_ISO_READ_COMMITTED, FBSQL_ISO_REPEATABLE_READ, FBSQL_ISO_SERIALIZABLE, or FBSQL_ISO_VERSIONED.