Steve Atkins wrote:
On Aug 28, 2008, at 12:09 PM, Scott Marlowe wrote:
On Thu, Aug 28, 2008 at 10:14 AM, Masis, Alexander (US SSA)
<alexander.masis@xxxxxxxxxxxxxx> wrote:
I was mapping C++ application code that works with mySQL to work with
Postgres.
There were a number of articles on line regarding the conversion from
mySQL to Postgres like:
SNIP
Well, in MySQL it's easy you just do:
"SELECT LAST_INSERT_ID();"
In Postgres, however it is not that simple. You have to know the
name of so called "insert sequence". Postgres has a system function for
that( SQL line below ).
In Postgres you will have to provide the table and column name(
"auto_increment" type in MySQL or "serial or bigserial" in Postgres).
Here is that SQL query that returns the last inserted ID:
"SELECT CURRVAL(
pg_get_serial_sequence('my_tbl_name','id_col_name'));"
That's the hard way. Starting with pgsql 8.2 you can do it much more
easily:
create table tester (id serial primary key, info text);
insert into tester (info) values ('this is a text string') returning id;
tada! All done, that insert will return the id for you.
Or lastval() if you want something bug-compatible with MySQL.
Cheers,
Steve
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.
Bill
