Data Set Options for Relational Databases

DBMASTER= Data Set Option

Designates which table is the larger table when you are processing a join that involves tables from two different types of databases.

Default value:	none
Valid in:	DATA and PROC steps (when accessing DBMS data using SAS/ACCESS software)
DBMS support:	Aster nCluster, DB2 under UNIX and PC Hosts, DB2 under z/OS, Greenplum, HP Neoview, Informix, Microsoft SQL Server, MySQL, Netezza, ODBC, OLE DB, Oracle, Sybase, Sybase IQ, Teradata

Syntax
Syntax Description
Details
Example
See Also

Syntax

DBMASTER=YES

Syntax Description

YES: designates which of two tables references in a join operation is the larger table.

Details

You can use this option with MULTI_DATASRC_OPT= to specify which table reference in a join is the larger table. This can improve performance by eliminating the processing that is normally performed to determine this information. However, this option is ignored when outer joins are processed.

Example

In this example, a table from an Oracle database and a table from a DB2 database are joined. DBMASTER= is set to YES to indicate that the Oracle table is the larger table. The DB2 table is the smaller table.

libname mydblib oracle user=testuser /*database 1 */
  pw=testpass path='myorapath'

libname mydblib2 db2 user=testuser /*database 2 */
  pw=testpass path='mydb2path';

proc sql;
   select * from mydblib.bigtab(dbmaster=yes), mydblib2.smalltab
bigtab.x=smalltab.x;