Re: [GENERAL] How do I insert and update into a table of arrays ofcomposite types via a select command?

Celia McInnis <celia.mcinnis@gmail.com> writes:
> My first question is: HOW do I populate this table, at first with arrays
> containing one element from the t_composite table?
> I have tried various things with no success.

You didn't say what you tried, but I imagine it was something like

regression=# insert into t_array select array[row('a','b','c'),row('d','e','f')];
ERROR:  column "data_array" is of type mytype[] but expression is of type record[]
LINE 1: insert into t_array select array[row('a','b','c'),row('d','e...
                                   ^
HINT:  You will need to rewrite or cast the expression.

Like it says, you need a cast.  You can either cast the array elements
individually:

regression=# insert into t_array select array[row('a','b','c')::mytype,row('d','e','f')::mytype];
INSERT 0 1

or just cast the whole ARRAY[] construct:

regression=# insert into t_array select array[row('a','b','c'),row('d','e','f')]::mytype[];
INSERT 0 1

although I think the latter only works in relatively late-model
Postgres, and it might make parsing a bit slower too.

                        regards, tom lane