Question

So I’m trying to run some SQL here through PHP’s PDO (which I don’t believe should be the problem) like such:

INSERT INTO example (
    d_id,
    s_id
) 
    VALUES (
    currval('d_id_seq'),
    currval('s_id_seq')
);

I have two sequences called d_id_seq and s_id_sec (lets pretend I have a table named d and a table named s, and this sequence is a column called ID and serial type).

Now, obviously I’m doing this wrong, as I get an error about the sequence not being used in this session:

Object not in prerequisite state: 7 ERROR: currval of sequence “d_id_seq” is not yet defined in this session

So, how should I write this?

Answer 1

The error means you did not “use” the sequence in this session (postgres connection). For instance you did not do any INSERTs on the table d.

Perhaps you have a bug in your code and reconnect to postgres after each query ?

A more convenient way to do it is to use INSERT RETURNING on your INSERTs. Then you get the ids.