Re: Truncate if exists

On 10/11/2012 09:22 PM, Simon Riggs wrote:

>>
>> That is a lot more typing and it's not exactly intuitive.  One obvious
>> thing that would help is a function pg_table_exists(text) that would
>> return true or false.  But even with that there's a lot of syntactic
>> sugar in there that is less than ideal: begin/end, dollar-quoting, do.
>>  Whatever becomes of this particular patch, I think we'd make a lot of
>> people really happy if we could find a way to dispense with some of
>> that stuff in simple cases.
>
> Yeh, definitely.
>
> So we just need a function called pg_if_table_exists(table, SQL) which
> wraps a test in a subtransaction.
>
> And you write
>
> SELECT pg_if_table_exists('foo', 'TRUNCATE TABLE foo');
>
> and we can even get rid of all that other DDL crud that's been added....
>
> and we can have pg_if_table_not_exists() also.
>

If we can do something like :

SELECT pg_if_table_exists('bar' , pg_if_table_exists('foo', 'TRUNCATE
TABLE foo, bar, foobar')) ;

or

SELECT pg_if_tables_exists('TRUNCATE TABLE foo, bar, foobar', 'foo',
'bar') ;

I say yes !


--
Sébastien Lardière
PostgreSQL DBA Team Manager
Hi-Media