Bookshelf Home | Contents | Index | PDF |
Implementing Siebel Business Applications on DB2 for z/OS > Customizing a Development Environment > About Siebel Tables and CLOB Columns > Converting LONG VARCHAR Columns to CLOB ColumnsSiebel application objects defined as LONG columns in the Siebel Schema are defined as LONG VARCHAR data types in the Siebel Repository. If you choose, you can store these columns as character large objects (CLOBs) on DB2 for z/OS. The default setting for these objects in the Siebel Schema is LONG because of the performance and storage characteristics of CLOBs in a DB2 for z/OS environment. These characteristics are described in Issues in Using CLOB Columns Instead of LONG VARCHAR Columns. However, it is recommended that you store LONG VARCHAR objects in the Siebel Repository as CLOBs in the following circumstances:
NOTE: If you choose to store LONG VARCHAR objects as CLOB objects, the logical and physical schema definitions of the object are not synchronized. As a result, when you run the dbchck utility, errors are generated for the relevant columns; these can be ignored. The Siebel installation, upgrade, and migration processes create all auxiliary objects necessary to support CLOBs so that their use is transparent. However, CLOBs are not enabled by default. To store Siebel application objects defined in the Siebel Repository as LONG VARCHAR data types as CLOB data types, perform the following procedure. To convert LONG VARCHAR columns in a table to CLOB columns
Issues in Using CLOB Columns Instead of LONG VARCHAR ColumnsIf you use a CLOB column instead of a LONG VARCHAR column, you do not run into the in-memory sort limit of DB2 for z/OS. This memory limitation does not occur because DB2 for z/OS does not account for the actual length of the CLOB column in estimating the total row width to be sorted in memory. However, there are a number of issues in using CLOB columns as follows:
|
Implementing Siebel Business Applications on DB2 for z/OS | Copyright © 2016, Oracle and/or its affiliates. All rights reserved. Legal Notices. | |