John,
> > What happens if someone manually shifted an element onto the front
> > of a Pg 1-D array, and the string was changed to '[-1:4]{.........}'
> > does your parser handle that?
>
> No, I've never even seen that syntax. Will the database itself actually
> return something like that? If so, can you give me an example that
> demonstrates it?
>
> What sort of querying can be done on ARRAY types?
> > cf. Pg's ANY() and ALL() functions.
> I'm not too familiar with the similar functions in Pg. Can you post some
> example SQL that uses the Pg array operators in a WHERE clause?
wasabi=> create table atest (x integer[]);
wasabi=> insert into atest (x) values ('{4,5,6}');
wasabi=> select * from atest;
x
---------
{4,5,6}
(1 row)
# ok - this is the 'simplified' array string representation
# when the array is 1-based.
wasabi=> update atest set x = array_prepend(3, x);
wasabi=> select * from atest;
x
-----------------
[0:3]={3,4,5,6}
# hmm - we prepended any element to the array so it is
# now 0-based, from 0 to 3. this is how Pg tells us.
# you can also use the array_dims() function
wasabi=> insert into atest (x) values (ARRAY[4,4,4,4,4]);
# alternate, nicer ARRAY syntax
wasabi=> select * from atest where 4 = ANY(x);
x
-----------------
[0:3]={3,4,5,6}
{4,4,4,4,4}
(2 rows)
# selected rows where 1 or more array elements had value 4
wasabi=> select * from atest where 4 = ALL(x);
x
-------------
{4,4,4,4,4}
(1 row)
# selected rows where every element in the array had value 4
NOTE: you must write 4=ANY(x) -- ANY(x)=4 fails syntax
Lots more information here:
http://www.postgresql.org/docs/8.1/interactive/arrays.html
http://www.postgresql.org/docs/8.1/interactive/functions-array.html
where 4 = ANY(x);
--
Torsten Seemann <[EMAIL PROTECTED]>
Victorian Bioinformatics Consortium
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