Chapter 4. Business resiliency 105
4.2.6 Accessibility and extensibility
Driving DB2 family compatibility and portability have been key focus areas for the
last several versions of DB2.
Extensibility
What makes DB2 a universal database (UDB)? DB2 is branded UDB when it
incorporates key object relational features, such as stored procedures, triggers,
user-defined functions, user-defines data types, and unstructured data
management. Currently, all DB2s, except for VM/VSE, are branded UDB.
Encoding scheme
Support for ASCII tables was added in Version 5, and Unicode was added in
Version 7. Version 8 completed the integration of multiple encoding schema
support by enabling SQL access to EBCDIC, ASCII, and Unicode in the same
SQL statement. The majority of the DB2 catalog tables has been converted to
Unicode. Such key DB2 processes as program preparation and SQL parsing are
done in Unicode.
New workload support
Type 2 and type 4 Java universal drivers are available for use with DB2 for z/OS,
whether your applications run in a zSeries LPAR or off the platform. When your
Java workloads run on the mainframe, the z/OS Application Connectivity to DB2
for z/OS (FMID HDDA210) provides the drivers for the z/OS platform.
The type 2 driver is best used when running in the same LPAR as DB2, using
DB2’s RRS attach facility. The type 4 driver is best used when in a different LPAR
using DRDA to communicate with DB2. The Java drivers that IBM delivers off the
mainframe are developed by the same team and are the same code base,
providing cross-platform compatibility.
Improvements for Open Database Connectivity (ODBC) and .Net continue. DB2
Version 8 delivers extended support and a new SQL cancel capability. See also
Chapter 6, “Readiness for new workloads” on page 135.
SQL enhancement
DB2 family compatibility and portability make it easier to move applications to
DB2 for z/OS to obtain the business resiliency benefits highlighted in this chapter,
without incurring significant application redesign. Figure 4-5 lists some of the
recent SQL improvements. It shows the top porting requirements from major
independent software vendor (ISV) partners. The top requirements were all
incorporated into Version 8 to assist in building and porting applications on DB2
for z/OS.
106 The Business Value of DB2 UDB for z/OS
Figure 4-5 SQL enrichment and portability
In addition, the new SQL Reference for Cross-Platform Development Version 2
guide has been published. You can download this document from the Web at:
http://www.ibm.com/software/data/db2/zos/v8books.html
This guide can assist you in avoiding the decreasing number of cross-platform
differences, which may cause porting problems.
WebSphere enhancements have been included to make these applications more
efficient. READ ONLY USING UPDATE LOCKS and IS NOT DISTINCT FROM
have been added to provide enhanced read, update, and null checking.
Stored procedures
Internal and external stored procedures are important in the support of network
computing. This encapsulated procedural logic, stored close to or in the
database, allows for efficient data access. DB2 supports external stored
procedures written in the languages that are available on the server. These
include COBOL, PL/I, Assembler, C, C++, REXX, and Java. Internal stored
procedures are written in the standard SQL stored procedures language, and are
common with the SQL stored procedures on DB2 UDB for Linux, UNIX, and
Windows. The DB2 Version 8 enhancement, increasing the SQL statement
length to 2 MB, is particularly helpful for these modules.
The DB2 Development Center assists in the building of Java and SQL stored
procedures in DB2 for z/OS. It also has an integrated debugger for SQL stored
procedures. At run time, Workload Manager supports the adjustment of tasks for
the stored procedure workload.
SQL enrichment
Common Table Expression and
Recursion
Multi-row INSERT and FETCH
GET DIAGNOSTICS
IDENTITY column enhancements
Sequences
Dynamic scrollable cursors
CURRENT PACKAGE PATH
Scalar fullselect
Materialized query tables
Unicode SQL, multiple CCSIDs
XML publishing
SQL access to client-side monitoring
variable
Session variables
Top portability requirements
Long SQL object names
Unicode table and SQL support
Scalar full select
Sequences
Common table expressions and
recursive SQL
Multiple distinct clauses
GROUP BY expression
Literals and predicates longer than
255 bytes
Multi-row INSERT and FETCH
SQL statements greater than 32 KB
Materialized query tables

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