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More About ALLBASE/DB2 CONNECT by Jim Nagler Database Management Systems Division ALLBASE/DB2 CONNECT FEATURES ALLBASE/DB2 CONNECT features the ability to access DB2 data using ALLBASE/SQL Interactive SQL (ISQL) or Information Access. ALLBASE/DB2 CONNECT provides access to DB2 using dynamically prepared SQL statements. The connection uses the SNA LU6.2 protocol to connect to CICS. A CICS transaction, SQLHost, is provided by Gupta Technologies, Incorporated to complete the attachment to DB2 and execute a DB2 dynamic application plan. Some restrictions apply; for example, DB2 SQL syntax must be used for DB2 access. DB2 data is translated for access by HP SQL. The standard data translation table can be modified for special needs for example, for use with European data. ALLBASE INTERACTIVE SQL After the connection is made, DB2 performs the syntax checks on the SQL language statements entered. DB2 resource access is based on the DB2 user name that matches the authid supplied in the ALLBASE NETUsers File. DB2 dynamic SQL statements are processed as the CICS transaction exchanges data with DB2. Some HP ISQL commands are restricted (for example, the LOAD and UNLOAD commands use the external format control option only). Full DB2 error messages are displayed for erroneous DB2 SQL statements. This feature is enabled when the CICS transaction is set to display the expanded error message format and the CICS system has loaded the expanded DB2 message generation routine. ISQL command files are supported and the executing process can be time initiated. INFORMATION ACCESS With this new ALLBASE product, Information Access DB2 data is accessed in the same manner as ALLBASE/SQL data by Information Access. Two tables need to be added to the DB2 system to enable Information Access to extract DB2 table names accessible to the connecting user. These tables are used to translate the DB2 system catalog entries into ALLBASE/SQL system catalog compatible data. Information Access command files are supported, and the executing process can be time initiated. Data Flow A number of interfaces are involved with this product. Tracing and control information are available at multiple locations. The following figure illustrates the location of error logs and trace points that are applicable to this product:Figure 9-4. ALLBASE/DB2 CONNECT Client-Server Diagnostic Information Connection to DB2 A typical connection sequence to DB2 might involve the following steps: * A CONNECT TO DB2 command is entered to ISQL, or a connection is made through Information Access. * The DBEnvironment name does not exist on the local XL system. * The DBEnvironment name does exist as a DB2 entry in the AliasDB File. * An entry exists in the NETUsers File, which provides an authid and password to be transmitted in the connection request. The HP 3000 userid.account,group that is active at the time of the connection attempt is used as a key to select the NETUsers File entry. * The authid/password is optionally validated by a CICS call to the IBM external security routine. * Based on data passed from the AliasDB File, transmission data buffers are allocated. The database name specified in the AliasDB File entry is checked for existence as a DB2 database. * The connection is completed. ALLBASE/DB2 CONNECT Installation ALLBASE/DB2 CONNECT provides an LU6.2 peer-to-peer connection between the HP 3000 accessing program and CICS. The peer-to-peer connection operates with parallel pieces on on both systems. With HP systems, the individual subsystems are often controlled by one person. With IBM systems, the subsystems may be controlled by different personnel. The following table summarizes the paired subsystem connection layers: ALLBASE/DB2 Peer-to-Peer Connection Layers ------------------------------------------------------------------------------------------------- | | | | | | Layer | HP 3000 | IBM | Comments | | | | | | ------------------------------------------------------------------------------------------------- | | | | | | Physical Layer | PSI Card | 37xx or Direct | Analog or Digital, up to | | | | Host Connect | 56Kb domestic, 65Kb in | | | | | Europe | | | | | | ------------------------------------------------------------------------------------------------- | | | | | | Physical Line | Modem/DSU | Modem/DSU | Optional switched line | | | | | support for the analog | | | | | connection | | | | | | ------------------------------------------------------------------------------------------------- | | | | | | Physical Unit | SNALink configured by | VTAM and NCP | Parameters must match for | | | NMMGR | generations | ID Block, ID Num, max | | | | | data, count of LUs, error | | | | | retry count, transmission | | | | | speed, use of NRZI, | | | | | station id, and optional | | | | | switched phone number | | | | | | ------------------------------------------------------------------------------------------------- | | | | | | Logical Unit | LU6.2 API configured by | VTAM List | Log Mode table entry, | | | NMMGR (SessionType) | | VTAM APPLID (used by | | | | | CICS), and the number of | | | | | LUs to autostart must be | | | | | compatible. | | | | | | ------------------------------------------------------------------------------------------------- | | | | | | Connection | The AliasDB file | CICS APPLID must | The Session Type defines | | parameters | specifications for: the | match, selected | CICS APPLID | | | LU6.2 API Session Type | security | | | | (including the parameters | mechanism must | | | | specified in this item), | accept the | | | | CICS transaction id, | parameters | | | | maximum row length (send | supplied in the | | | | and receive buffer | connection | | | | sizes), timeout, and | request, LOGMODE | | | | trace option are merged | entry will be | | | | with the IBM parameters; | used to negotiate | | | | the NETUser file entry | the bind | | | | for the connecting | | | | | user.account,group must | | | | | specify an acceptable DB2 | | | | | authid and password. | | | | | | | | ------------------------------------------------------------------------------------------------- | | | | | | DB2 | The NETUser File entry is | Security | Installation options used | | Authorizations | the source for the authid | Mechanism will | with CICS may override | | | | check the authid, | the authid placed in the | | | | GRANTS, and | connect request | | | | REVOKEs, control | | | | | access to TABLES | | | | | and VIEWS for | | | | | this authid | | | | | | | ------------------------------------------------------------------------------------------------- Additional information is available in the following publications: * ALLBASE/DB2 CONNECT Data Sheet (P/N 5952-3212) * ALLBASE/DB2 CONNECT Users Guide (P/N 30700-90001)
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