Question

I know I can insert an array into a Postgres database with pg_query.

INSERT into table (field) VALUES ('{{element, element},{}}')

But how about using pg_insert?

$array["field"] = "{{element, element},{}}";
$result = pg_insert($con, "table", $array);

Will the string {{element, element},{}} be actually inserted into field as a 2D Postgres array?

I’ve always wanted to test that out but currently I don’t have any PostgreSQL DB to test with..

Answer 1

I just ran your specific example.

(1) in Postgres:

CREATE TABLE atable (afield text[][]);

(2) in PHP:

$array["afield"] = "{{'element', 'element'},{}}";
$result = pg_insert($this->conn, "atable", $array);

And I got the following error:

Notice: pg_insert(): Unknown or system data type '_text' for 'afield' in ...

I tried playing around with the array value: make it 2×2 array, one-dimensional, etc., etc. – the same result. I even changed the table to have the field as one-dimensional array: text[] and changed the code accordingly – and I still get the same result.

I started digging further and found the following on PHP documentation for pg_insert:

This function is EXPERIMENTAL. The behaviour of this function, its
name, and surrounding documentation may change without notice in a
future release of PHP. This function should be used at your own risk.

Basically, it’s pretty buggy and shouldn’t be used. Interestingly, using

pg_query("INSERT INTO...")

works just fine. Hopefully, this answers your question. 🙂