Dynamically generate GRANT SQL from syscat.tabauth table - sql

Question

I have a database (on DB2 9.7) A in which suppose I have tables X,Y,Z...n
Now I have created same tables X,Y,Z...n in database B. I want to provide same GRANTs to users in database B as it was in database A. So based on SYSCAT.TABAUTH I am trying to generate GRANT SQLs. I have written the following query for it:
db2 "select 'GRANT '||
case INSERTAUTH
WHEN 'Y' THEN 'INSERT,'
WHEN 'N' THEN ' '
END||
case ALTERAUTH
WHEN 'Y' THEN 'ALTER,'
WHEN 'N' THEN ' '
END||
case DELETEAUTH
WHEN 'Y' THEN 'DELETE,'
WHEN 'N' THEN ' '
END||
case SELECTAUTH
WHEN 'Y' THEN 'SELECT,'
WHEN 'N' THEN ' '
END||
case UPDATEAUTH
WHEN 'Y' THEN 'UPDATE,'
WHEN 'N' THEN ' '
END||
' ON '||TABSCHEMA||'.'||TABNAME||' TO '||GRANTEE from SYSCAT.TABAUTH
where INSERTAUTH='Y' OR ALTERAUTH='Y' OR DELETEAUTH='Y' OR SELECTAUTH='Y' OR UPDATEAUTH='Y'"
However, the problem I am facing is of the additional ',' at end.
Suppose a user has only Insert auth, the above query will generate GRANT sql as:
GRANT INSERT, ON SCHEMA.TABLE TO GRANTEENAME
or if user has insert and select grants then:
GRANT INSERT,SELECT, ON SCHEMA.TABLE TO GRANTEENAME
How can I solve this? Please help..

Answer 1

This is what I finally made and it works fine:
db2 "SELECT
'GRANT ' ||
SUBSTR(T.AUTHSTRING, 1 ,LENGTH(T.AUTHSTRING) - 1)
|| T.TABNAME
FROM(
select
case INSERTAUTH
WHEN 'Y' THEN 'INSERT,'
WHEN 'N' THEN ''
END
||
case ALTERAUTH
WHEN 'Y' THEN 'ALTER,'
WHEN 'N' THEN ''
END
||
case DELETEAUTH
WHEN 'Y' THEN 'DELETE,'
WHEN 'N' THEN ''
END
||
case SELECTAUTH
WHEN 'Y' THEN 'SELECT,'
WHEN 'N' THEN ''
END
||
case UPDATEAUTH
WHEN 'Y' THEN 'UPDATE,'
WHEN 'N' THEN ''
END
AS AUTHSTRING,
' ON ' ||TRIM(TABSCHEMA)||'.'||TRIM(TABNAME)||' TO ' ||GRANTEE AS TABNAME
from SYSCAT.TABAUTH
where INSERTAUTH='Y'
OR ALTERAUTH='Y'
OR DELETEAUTH='Y'
OR SELECTAUTH='Y'
OR UPDATEAUTH='Y'
) AS T"

Answer 2

You can always push the dynamic part into a sub-query, and then use a combination of LENGTH() and SUBSTR() to trim off the extra comma. Here is your SQL I modified a bit:
SELECT
'GRANT' ||
SUBSTR(T.AUTHSTRING, 1 LENGTH(T.AUTHSTRING) -1)
|| T.TABNAME
FROM(
select
case INSERTAUTH
WHEN 'Y' THEN 'INSERT,'
WHEN 'N' THEN ' '
END
||
case ALTERAUTH
WHEN 'Y' THEN 'ALTER,'
WHEN 'N' THEN ' '
END
||
case DELETEAUTH
WHEN 'Y' THEN 'DELETE,'
WHEN 'N' THEN ' '
END
||
case SELECTAUTH
WHEN 'Y' THEN 'SELECT,'
WHEN 'N' THEN ' '
END
||
case UPDATEAUTH
WHEN 'Y' THEN 'UPDATE,'
WHEN 'N' THEN ' '
END
AS AUTHSTRING,
' ON ' || RTRIM(TABSCHEMA) || '.' || RTRIM(TABNAME)||' TO ' || RTRIM(GRANTEE) AS TABNAME
from SYSCAT.TABAUTH
where INSERTAUTH='Y'
OR ALTERAUTH='Y'
OR DELETEAUTH='Y'
OR SELECTAUTH='Y'
OR UPDATEAUTH='Y'
) AS T
I tested this, and it worked on LUW 9.7 and z/OS 9.1.