Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
>> SQL standard:
>
>> <SQL-data access indication> ::=
>> NO SQL
>> | CONTAINS SQL
>> | READS SQL DATA
>> | MODIFIES SQL DATA
>
> Huh. I understand three of those, but what is the use of CONTAINS
> SQL? Seems like that would have to be the same as the last one,
> or maybe the next-to-last one if you're prepared to assume it's
> read-only SQL.
On a quick search of the spec, the best I was able to tell was that
you are required to use "CONTAINS SQL" if the language is SQL.
Perhaps it figures that the database engine can determine the
read/write behavior directly if the language is SQL, and you tell it
what it does if you're coding in some other language.
-Kevin