Re: [PATCH] Add pg_get_trigger_ddl() to retrieve the CREATE TRIGGER statement - Mailing list pgsql-hackers

Apologies, I forgot to add a new version of the patch with the documentation change.

This is my first time doing this.

your documentation and the function's comment specifically say that the
function take a trigger name and a table name, so it should not use
regclass type, which allows OID as input as well.

Thanks for pointing that out in the documentation.

I think the regclass type actually makes it easier to use because you can input a name or OID, but you're right in that it is essentially 'table_name'::regclass::oid. However, isn't the point of the regclass type to make it easier to do table lookups? In that case, using a name seems easier.

I think you should change the documentation. It seems better to use the regfoo types where available to save a lot a code duplication.

There is already a family of pg_get_[xxx]def functions available in
PostgreSQL. pg_get_triggerdef() being one of them and it already can take
OID as input and output the same text, so regclass type is not necessary.

True, but you have to look for the trigger OID. If you have more than one table using the same trigger name, then you have to figure that out as well. Using names over OIDs seems more intuitive and less error prone than having to look up all the OIDs in my opinion. Also, having the added option of using an OID as well shouldn't be frowned upon since that's what it's using under the hood with regclass, but I understand what you're saying about pg_get_triggerdef(OID) doing the same thing with the OID only.

Yes, what this function buys us anything is that you don't need to get the trigger OID.

 

The term "DDL statement" may be a little misleading here, it does not return
the actual DDL statements executed to create the trigger. The documentation for
"pg_get_triggerdef" calls this statement as follows :

"the creating command for a trigger. (This is a decompiled reconstruction,
not the original text of the command.)"

True, Cary. Appreciate calling that out. I can fix that in the documentation as well. 

by "DDL statement" we mean a statement that would create the object as it exists now if it were not already present, not the original creation statement. I don't think we need to state that all over the place.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com