Scott Marlowe wrote:
On Thu, Aug 28, 2008 at 3:38 PM, Bill <pg@xxxxxxxxxx> wrote:
I am new to PostgreSQL but it seems to me that lastval() will only work if
the insert does not produce side effects that call nextval(). Consider the
case where a row is inserted into a table that has an after insert trigger
and the after insert trigger inserts a row into another table which has a
serial primary key. In that case I assume that lastval() will return the
value from the serial column in the second table.
I use returning almost exclusively now.
RETURNING is the best option. It makes all your INSERT and UPDATE
statements feel like SELECTs. It avoids the round-trip back to the
server just to ask for the unique id generated by the previous statement.
INSERT INTO mytable (col1, col2)
VALUES (value1, value2)
RETURNING col_value_from_seq_that_we_dont_care_about_the_name;
I use RETURNING for all my insert and UPDATE statements now. Usually
I'll return the primary key for the table, but sometimes I return a
column that is created by one of my triggers. It's awesome to be able
to do this in one query.
-- Dante
