On Wed, Jun 18, 2008 at 12:39 PM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > None. There is no type coercion there --- what that is really > specifying is invocation of the int data type's input function > on the given string. I thought that something like this may be this was the case. > I don't think your approach is going to work; you would have to > make your client programs emit things like > > insert into mytab(integercol) values (''::varchar) > > in order to get a runtime varchar-to-int cast to be applied. > At that point you might as well fix them properly. I see. Other than directly modifying int4in (is this the one?), is there a way to plug-in our modified empty string handling logic? I'm picturing a scenario where we write write a wrapper function that tests for empty strings and returns NULL, else just calls into int4in, and then dynamically load this function, and finally update the corresponding rows in pg_proc? Is this even possible? thanks for your explanation Tom, Dave