Thiemo Kellner <> writes:
> I try to implement SCD2 on trigger level and try to generated needed 
> code on the fly. Therefore I need to read data about the objects in the 
> database. So far so good. I know of the information_schema and the 
> pg_catalog. The documentation for the information_schema states that it 
> 'is defined in the SQL standard and can therefore be expected to be 
> portable and remain stable'. I can think of a sensible meaning of 
> portable. One cannot port it to MariaDB, can one?

If MariaDB implements information_schema according to the spec, then
yes.  (If they don't, that's something to complain about to them,
not us.)

> I created following query to get 
> the index columns of an index. I fear breakage when not run on the 
> specific version I developed it against. Is there a more elegant way by 
> the information_schema?

No, because indexes are not a part of the SQL standard.  (I'm not here
to debate the wisdom of that choice; we didn't make it.)  You can get
information about constraints out of the information_schema, so to the
extent that what you're interested in is the indexes underlying PK or
UNIQUE constraints, that's an option.  Otherwise, you're dealing with an
implementation-specific feature and you shouldn't be surprised that the
way of finding out about it is likewise implementation-specific.

FWIW, the stuff used in your sample query has all been there for a
very long time; we don't like to break plausible client queries lightly.

                        regards, tom lane

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