Considerations in Choosing the Database CCSID
The current Siebel CRM release supports ASCII- and EBCDIC-based coded character set IDs (CCSIDs) for all versions of DB2 for z/OS, and Unicode character set IDs on all versions of DB2 for z/OS, New Function Mode and later releases. The database CCSID you use determines a number of factors, for example, the sort order used in list applets.
Review Siebel CRM Update Guide and Release Notes on My Oracle Support for information about known restrictions; for example, the following features are not supported on databases with EBCDIC code pages:
- Web Client migration 
- Siebel Data Warehouse 
- Siebel Dun and Bradstreet server components 
You must run development databases with ASCII or Unicode code pages, because databases with EBCDIC code pages do not support the following procedures in a development environment upgrade:
- Merging prior configuration changes into a new custom configuration repository (for upgrades only) 
- Publishing a new Siebel Runtime Repository 
You can use an ASCII-, an EBCDIC-, or a Unicode-based CCSID to create your Siebel Schema, but, if you mainly use single-byte character sets, it is recommended that you use ASCII or EBCDIC CCSIDs to minimize storage space requirements. Review the following recommendations:
- Use an ASCII-based encoding scheme to reduce the overhead required for character conversion. Character conversion is performed by Distributed Relational Database Architecture (DRDA), between the database and the midtier ASCII servers. 
- Use a Unicode-based encoding scheme if you require a character set that includes many characters that do not fit well in the ASCII or EBCDIC character set, for example, double-byte character sets for Chinese, Japanese, and Korean characters. 
You can partition table spaces on a database with either an ASCII, an EBCDIC or a Unicode code page, so that limit keys reflect the sort sequence difference between ASCII, EBCDIC and Unicode. For more information, see Configuring the Siebel Database Layout.