Re: What is the impact of changing the system CCSID?

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 23/09/2004, at 7:15 AM, kirkg@xxxxxxxxxxxxx wrote:

> What is the impact of changing the system CCSID (sysval QCCSID) from 
> 65535
> to say 37? How is data affected on the system?

You should read the appropriate documentation on this subject. IBM has 
provided a number of resources to assist you in choosing the correct 
value. See section 4.2.5 of the Road Map for Changing to PowerPC 
Technology for considerations before changing QCCSID. Additional 
information about QCCSID can be found in section 2.3.22 of the Work 
Management Guide, section 3.1.1 of the National Language Support 
manual, and many sections of the AS/400 International Application 
Development manual. Much of this information is now in the Information 
Centre under Globalisation. READ IT!

Existing data is not affected (i.e., no conversion process occurs). 
Because no sites changed the QCCSID system value to something other 
than 65535 when they should have back in VRM230 (possibly earlier) IBM 
created a Job Default CCSID value to compensate. This value is derived 
from your job's LANGID which in turn is inherited from the QLANGID 
system value. This value is used when physical files are created so ...

... as long as your Job Default CCSID is 37 your data will probably be 
in CCSID 37 too. If so there will be little or no effect on your 
existing applications when you change QCCSID. However, you should not 
do this blindly. If you do have files with data in a different CCSID 
then behaviour may change and CCSID conversion from file CCSID to job 
CCSID may now occur where it previously did not.

You should determine whether that change is safe for your environment 
by evaluating your data files, your use of conversion functions such as 
iconv, silly assumptions about EBCDIC/ASCII conversion, and other stuff 
discussed in the references I gave above.

For most USA sites changing from 65535 to 37 will be painless but YOU 
need to perform due diligence.

Regards,
Simon Coulter.
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