SAS/ACCESS 9.2 for Relational Databases: Reference, Fourth Edition

SAS/ACCESS Interface to DB2 Under z/OS 4 DB2 Attachment Facilities (CAF and RRSAF) 531DDF Communication DatabaseDB2 Distributed Data Facility (DDF) Communication Database (CDB) enables DB2z/OS applications to access data on other systems. Database administrators areresponsible for customizing CDB. SAS/ACCESS Interface to DB2 under z/OS supportsboth types of DDF: system-directed access (private protocol) and Distributed RelationalDatabase Architecture.System-directed access enables one DB2 z/OS subsystem to execute SQL statementson another DB2 z/OS subsystem. System-directed access uses a DB2-only privateprotocol. It is known as a private protocol because you can use only it between DB2databases. IBM recommends that users use DRDA. Although SAS/ACCESS Interface toDB2 under z/OS cannot explicitly request a connection, it can instead perform animplicit connection when SAS initiates a distributed request. To initiate an implicitconnection, you must specify the LOCATION= option. When you specify this option, thethree-level table name (location.authid.table) is used in the SQL statement thatSAS/ACCESS Interface to DB2 under z/OS generates. When the SQL statement thatcontains the three-level table name is executed, an implicit connection is made to theremote DB2 subsystem. The primary authorization ID of the initiating process must beauthorized to connect to the remote location.Distributed Relational Database Architecture (DRDA) is a set of protocols that enablesa user to access distributed data. This enables SAS/ACCESS Interface to DB2 underz/OS to access multiple remote tables at various locations. The tables can be distributedamong multiple platforms, and both like and unlike platforms can communicate withone another. In a DRDA environment, DB2 acts as the client, server, or both.To connect to a DRDA remote server or location, SAS/ACCESS Interface to DB2under z/OS uses an explicit connection. To establish an explicit connection,SAS/ACCESS Interface to DB2 under z/OS first connects to the local DB2 subsystemthrough an attachment facility (CAF or RRSAF). It then issues an SQL CONNECTstatement to connect from the local DB2 subsystem to the remote DRDA server beforeit accesses data. To initiate a connection to a DRDA remote server, you must specify theSERVER= connection option. By specifying this option, SAS uses a separate connectionfor each remote DRDA location.DB2 Attachment Facilities (CAF and RRSAF)By default, SAS/ACCESS Interface to DB2 under z/OS uses the Call AttachmentFacility (CAF) to make its connections to DB2. SAS supports multiple CAF connectionsfor a SAS session. Thus, for a SAS server, all clients can have their own connections toDB2; multiple clients no longer have to share one connection. Because CAF does notsupport sign-on, however, each connection that the SAS server makes to DB2 has thez/OS authorization identifier of the server, not the authorization identifier of the clientfor which the connection is made.If you specify the DB2RRS system option, SAS/ACCESS Interface to DB2 under z/OSengine uses the Recoverable Resource Manager Services Attachment Facility (RRSAF).Only one attachment facility can be used at a time, so the DB2RRS or NODB2RRSsystem option can be specified only when a SAS session is started. SAS supportsmultiple RRSAF connections for a SAS session. RRSAF is a new feature in DB2 Version5, Release 1, and its support in SAS/ACCESS Interface to DB2 under z/OS was new inSAS 8.The RRSAF is intended for use by SAS servers, such as the ones that SAS/SHAREsoftware use. RRSAF supports the ability to associate a z/OS authorization identifierwith each connection at sign on. This authorization identifier is not the same as theauthorization ID that is specified in the AUTHID= data set or LIBNAME option. DB2