Chapter 2 Migrating
from Previous Installations

Installation and Administration Guide for Mainframe Connect for DB2 MVS-CICS

Chapter 1 Understanding MainframeConnect for DB2/MVS-CICS

Chapter 1

Understanding MainframeConnect for DB2/MVS-CICS

MainframeConnect for DB2/MVS-CICS is part of the Sybase Enterprise Connect Studio. For an explanation of how MainframeConnect for DB2/MVS-CICS works with other Mainframe Connect products, see the Overview Guide for the Mainframe Connect Integrated Product Set.

MainframeConnect for DB2/MVS-CICS software provides client applications access to DB2 and other data sources on an IBM mainframe running MVS/CICS.

MainframeConnect for DB2/MVS-CICS is a unified version of two previous products:

MDI Access Server for MVS-CICS Version 2.5
OmniSQL Access Module Version 10.1

This chapter provides an overview of MainframeConnect for DB2/MVS-CICS and contains the following sections:

MainframeConnect for DB2/MVS-CICS functionality

MainframeConnect for DB2/MVS-CICS works with DirectConnect, which is a separate Sybase product that provides the communication link between a mainframe and a remote network of clients. MainframeConnect for DB2/MVS-CICS uses Open ServerConnect for:

Communication to multiple protocols
Character set support
Character set customization

Open ServerConnect

Open ServerConnect uses Open Server architecture to allow the mainframe to act as a server. Open ServerConnect is available for CICS, IMS and native OS/390. MainframeConnect for DB2/MVS-CICS is an application that runs on top of Open ServerConnect. Together, they support the features described in the following subsections.

Multiple Connectivity and Protocols

MainframeConnect for DB2/MVS-CICS supports multiple protocols:

SNA LU 6.2 Connectivity
TCP/IP Connectivity (for Open Server and DB2, which is supported using the CICS Sockets Interface with the IBM MVS TCP/IP product

Long-Running Transactions

MainframeConnect for DB2/MVS-CICS supports user-defined, long-running transactions. Because transactions can remain active after all results are sent, multiple requests can participate in the same unit of work. Therefore, you have more control over individual or group commits or rollbacks on mainframe databases.

Internationalization

MainframeConnect for DB2/MVS-CICS (with Open ServerConnect) supports the following character sets:

ascii_8, iso-1
cp-850
cp-437, eucjis
SJIS
dec-kanji
roman8 (for HP)
mac
cp819 (UNIX ascii iso_1)
cp500 (mainframe ebcdic iso_1)

In addition, messages are provided in multiple languages. You can specify a national language, such as U.S. English, French, or German for messages.

Character Set Customization

MainframeConnect for DB2/MVS-CICS provides character sets that you can customize if you want to change languages. You can create up to 99 new character sets by modifying the shipped base tables.

Access to Relational and Non-Relational Data

In addition to relational data support, MainframeConnect for DB2/MVS-CICS provides access to non-relational data through RSPs and RPCs. RSPs require Open ServerConnect API. For more information, see the Programmer's Reference for Open ServerConnect. RSP, PL/1, and COBOL versions of this guide are available.

Dynamic SQL DB2 Data Access

MainframeConnect for DB2/MVS-CICS supports the following:

Cursor and dynamic events
Updates and inquiries against DB2 data using DB2 dynamic SQL
Dynamic access to DB2 data and CICS programs

Non-Truncated Columns

MainframeConnect for DB2/MVS-CICS supports columns for LONG VARCHAR and LONG VARBINARY without truncation. In addition, if the LONG VARCHAR is greater than 255 bytes, then truncation is not required for data returned from these datatypes.

User Datatypes

Client applications can process user datatypes that return descriptive information about DB2 columns.

Exit Routines

MainframeConnect for DB2/MVS-CICS provides request, result and parse exit routines.

Other Features

MainframeConnect for DB2/MVS-CICS also supports the following features:

Translation between DB2 and Sybase datatypes and error codes
DB2 catalog queries
31-digit decimals; MainframeConnect for DB2/MVS-CICS supports the DB2 extension to its decimal datatype, DECIMAL(31,31)
LONG VARCHARs (literal strings greater than 254 bytes) can be embedded in an insert or update language statement

MainframeConnect for DB2/MVS-CICS communication

This section lists the products MainframeConnect for DB2/MVS-CICS communicates with and explains the communication path.

Components of MainframeConnect for DB2/MVS-CICS

The MainframeConnect for DB2/MVS-CICS product consists of the transaction AMD2 and uses the Host Request Library DB2 Table, both of which reside on the mainframe.

AMD2 was formerly SYRT (Sybase Request Tool) or MDI.

Transaction Processor AMD2

AMD2 is the default name of the CICS transaction in MainframeConnect for DB2/MVS-CICS that allows clients to submit SQL statements or RSP requests to DB2.

A separate installed CICS region with AMD2 is required for each DB2 subsystem accessed.

DirectConnect invokes AMD2 when it sends a client SQL request to the mainframe. AMD2 then submits the SQL request to DB2, using the DB2 dynamic SQL facility.

AMD2 returns DB2 results and messages to DirectConnect and then terminates. However, in the case of long transactions or allocate on connect, AMD2 terminates only after the client explicitly ends the transaction.

Host request library DB2 table

The host request library is a DB2 table for centrally storing SQL statements. This library makes the requests available to all DirectConnect users.

MainframeConnect for DB2/MVS-CICS retrieves the specified SQL request from the host request library and submits the request to DB2 for processing. MainframeConnect for DB2/MVS-CICS returns the results of the request to the client application.

Communication with other products

MainframeConnect for DB2/MVS-CICS and DirectConnect handle the communications between the client application, DB2, and other products.

The products discussed in the following sections comprise the major parts of the communication path from a client to DB2. They affect either the processing and/or the content of client requests.

Other Mainframe products

MainframeConnect for DB2/MVS-CICS interacts with these mainframe products:

DB2
CICS
MVS
IBM TCP/IP and InterLink (through Open ServerConnect interface)
Resource Access Control Facility ( RACF), Advanced Communications Function 2 ( ACF2), or TopSecret
SNA LU 6.2 (through Open ServerConnect interface)

DirectConnect for MVS

Client application requests use DirectConnect to access MainframeConnect for DB2/MVS-CICS on the mainframe. Client application requests are initiated by Sybase and third-party, client applications.

Connectivity between DirectConnect and MainframeConnect for DB2/MVS-CICS is achieved using SNA LU 6.2 or TCP/IP connectivity and the Tabular Data Stream (TDS) protocol. See the Installation Guide for DirectConnect for MVS for more information.

Client applications

Client applications send requests to DirectConnect (or to other servers for forwarding to DirectConnect). Client requests can be sent through ODBC, DB-Library, CT-Library, or Open Client applications; for example, isql, Data Workbench, APT Workbench, and front-end products from independent software vendors.

DirectConnect provides the link between MainframeConnect for DB2/MVS-CICS and the clients. Thus, after MainframeConnect for DB2/MVS-CICS is installed and configured, the clients do not need to consider communication issues with MainframeConnect for DB2/MVS-CICS.

Other servers

CIS funtionality in ASE (formally OmniConnect), Adaptive Server, and Replication Server are separate Sybase products that work with DirectConnect and can be optional parts of the MainframeConnect for DB2/MVS-CICS communication path.

All further references to "CIS functionality in ASE (formally OmniConnect)" will be identified as "ASE/CIS."

MainframeConnect communication path for three-tier environments

For client access to DB2 data, MainframeConnect for DB2/MVS-CICS must be installed on the mainframe and DirectConnect must be installed on a LAN server. MainframeConnect for DB2/MVS-CICS and DirectConnect work together to provide DB2 data to clients as follows:

A client sends SQL requests to DirectConnect.
DirectConnect forwards the requests to the CICS transaction (AMD2) on the mainframe (using SNA or TCP/IP connectivity on the LAN server).
AMD2 processes the client SQL requests using the dynamic SQL capabilities of DB2.
AMD2 returns the DB2 result sets and messages to DirectConnect (using SNA or TCP/IP connectivity on the LAN server).
DirectConnect returns the results and messages to the client.

See the following figure for an illustration of this process.

Figure 1-1: MainframeConnect communication path for three-tier raster

MainframeConnect communication path for two-tier environments

For client access to DB2 data (gatewayless), MainframeConnect must be installed on the mainframe. MainframeConnect provides DB2 data to clients as follows:

A client sends SQL requests to the CICS transaction (AMD2) on the mainframe (using TCP/IP connectivity).
AMD2 processes the client SQL requests using the dynamic SQL capabilities of DB2.
AMD2 returns the DB2 result sets and messages to the client (using TCP/IP connectivity).

See the following figure for an illustration of this process.

Figure 1-2: MainframeConnect communication path for two-tier gatewayless raster


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