db2 REGEXP_INSTR 问题与大输入字符串

Question

DB2 Regular expression REGEXP_INSTR works perfectly using host variables(pl1 program), but somehow it has issues when the input string has more than 360 characters, trailing spaces would not be a issue.

        3 Info          CHAR(378),

       EXEC SQL
       SELECT REGEXP_INSTR(:Info,
                           :RG_EXPR,
                           1,
                           1)
             INTO   :REGEXP_START
             FROM SYSIBM.DUAL;

Error Message:

SQL0302N The value of a host variable in the EXECUTE or OPEN statement is out of range for its corresponding use. .SQL STATE=22001.

Edit: Issue seems to be resovlved when I use a VAR CHAR variable instead. But this issue occurs with non-var char field with large inputs.

Answer 1

This is less to do with regexp_instr() than simple fundamentals.

Instead, it concerns Db2 database fundamentals, specifically the maximum length of fixed length character strings.

A fixed length character string (data type CHAR in SQL) in Db2 can occupy between 1 and 255 bytes.

A variable length character string (database type VARCHAR and others) can occupy between 1 and 32,672 bytes.

If you need longer length strings, then you need to use large objects (for example CLOB which allows up to 2gigabytes).

Please refer to the documentation for your Db2-version on your Db2 platform (z/os, i series, linux/unix/windows).

Your host variables need to reflect these rules, and your host variables must match (or be fully compatible with) the database columns or result-set columns to/from which they are assigned.