Mixed EUC and double-byte client and database considerations
The administration of database objects
in mixed EUC and double-byte code page environments is complicated
by the possible expansion or contraction in the length of object names
as a result of conversions between the client and database code page.
In particular, many administrative commands and utilities have documented
limits to the lengths of character strings that they can take as input
or output parameters.
These limits are typically enforced
at the client, unless documented otherwise. For example, the limit
for a table name is 128 bytes. It is possible that a character string
that is 128 bytes under a double-byte code page is larger, say 135
bytes, under an EUC code page. This hypothetical 135-byte table name
would be considered invalid by such commands as REORG TABLE if
used as an input parameter, despite being valid in the target double-byte database.
Similarly, the maximum permitted length of output parameters might
be exceeded, after conversion, from the database code page to the
application code page. This might cause either a conversion error
or output data truncation to occur.
If you expect to use administrative commands and utilities extensively
in a mixed EUC and double-byte environment, define database objects
and their associated data with the possibility of length expansion
past the supported limits. Administering an EUC database from a double-byte
client imposes fewer restrictions than administering a double-byte
database from an EUC client. Double-byte character strings typically
are equal or shorter than the corresponding EUC character string.
This characteristic generally leads to fewer problems caused by enforcing
the character string length limits.
Note: In the case of SQL statements,
validation of input parameters is not conducted until the entire statement has been converted
to the database code page. Thus you can use character strings that
might be technically longer than allowed when represented in the client
code page, but which meet length requirements when represented in
the database code page.