Let's say I have two tables, foo and bar:
CREATE TABLE foo( foo_id serial NOT NULL, count integer NULL, PRIMARY KEY(foo_id) ); CREATE TABLE bar( bar_id serial NOT NULL, foo_id SERIAL NOT NULL REFERENCES foo(foo_id), PRIMARY KEY(bar_id) );
When something gets inserted into
bar with a given
foo_id, the corresponding record in
foo should have its count incremented. How exactly do I go about doing this? I'm fairly new to databases in general.
INSERT INTO foo VALUES(1, 0); INSERT INTO bar VALUES(1, 1);
At the second line,
count should be incremented at the record for
foo_id = 1.
I also need to the count decremented on a delete, but I'm sure that's pretty similar to incrementing on insert.