Dwight Emmons wrote:

[Why did you post this to pgsql-patches of all places? it should properly have gone to pgsql-general, I think]

My company is currently using version 7.2 and would like to convert to the latest version. Unfortunately, version 7.3 implicitly casts a null text to an int4. For example:

Create table employee_table (

employee_id integer

employee_name text

employee_address text);

Select * from employee_table where employee_id = ‘’;

That's not a NULL at all, it's an empty string. You really need to understand the difference between the two.

Old editions of postgres did take an empty string literal as a 0 for ints, modern version quite rightly reject it as invalid. use NULL if you mean NULL and 0 if you mean 0.

When executing this select statement in version 7.2 the null will be converted to an int zero and not fail. In version 8.2 it fails. We have over 20,000 lines of code and do not want to modify and test all of it. Has anyone come across this problem? (I am not interested in debating the theory of nulls versus zero. I am just trying to avoid unnecessary costs).

I am not a DBA, and am looking for explicit instructions to solve this problem. Is it possible to create a CAST after upgrading to version 8.2? My research tells me the following cast was no longer implemented after version 7.2. Will executing the following CAST solve my problem?

CREATE CAST (text AS int4) WITH FUNCTION int4(text);

If so, can someone give me instructions as to executing this statement?

Any help is appreciated….

This has nothing to do with casts, I believe - it has to to with what the input routines accept.

I strongly suspect that renovating your code is your best choice, much as that might pain you.



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