On 1/30/2015 10:44 PM, David Barrett wrote:
Is it possible to create a trigger that calls a custom function and passes
in NEW.*?
Not literally NEW.* . You'll have to spell out individual columns as
parameters.
2) I'm *assuming* if you pass a "*" into that function, it'll just call
that function with however many columns are available.
Your assumption is incorrect. If I recall correctly, the syntax
"myFunc(*)" is accepted, and is equivalent to "myFunc()" - that is, no
parameters are passed. Pretty much the only reason to allow this syntax
is to accept "count(*)".
3) It seems that there is a way to create a custom trigger that has no
byproduct but to call SELECT. The only reason I can imagine you'd want to
do that is to call a custom function. But can I call that function with
all columns using a *? (I can't quite figure this out from the docs alone.)
Well, you could have tested it, and discovered it didn't work. You don't
even need a custom function, you could have used a built-in one.
SELECT myFunc( NEW.* );
That would produce a syntax error.
Are these assumptions correct, and should the above generally work?
No, and no.
My
goal is to execute myFunc() every time there's an INSERT/UPDATE/DELETE on a
given table -- but I want myFunc() to be reusable and not need to know the
structure of the table it's being called on.
I'm not sure how the necessity of myFunc(NEW.*) syntax follows from
this. Why can't the trigger call myFunc(new.colA, new.colB)?
You can write a variadic custom function (one that can be called with an
arbitrary number of arguments), if that's what you are asking.
--
Igor Tandetnik
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