int odbc_connect (string dsn, string user, string password [, int cursor_type])
Returns an ODBC connection id or 0 (false) on error.
The connection id returned by this functions is needed by other ODBC functions. You can have multiple connections open at once. The optional fourth parameter sets the type of cursor to be used for this connection. This parameter is not normally needed, but can be useful for working around problems with some ODBC drivers.
With some ODBC drivers, executing a complex stored procedure may fail with an error similar to: "Cannot open a cursor on a stored procedure that has anything other than a single select statement in it". Using SQL_CUR_USE_ODBC may avoid that error. Also, some drivers don't support the optional row_number parameter in odbc_fetch_row(). SQL_CUR_USE_ODBC might help in that case, too.
The following constants are defined for cursortype:
SQL_CUR_USE_IF_NEEDED
SQL_CUR_USE_ODBC
SQL_CUR_USE_DRIVER
SQL_CUR_DEFAULT
For persistent connections see odbc_pconnect().