PostgreSQL trigger function to capture updated field

Question

I am querying data from server to update fields in my local DB.

But, I have more than 100 columns hence I just want to know which column has new value(different than previous) so that I can use only those fields to prepare/make/build update command to my local DB.

EXAMPLE: I have 100 columns already in my DB. Same row in server has been update. Now that I have fetched all those 100 columns from server.(Stored in list object to make prepare statement in Java). Only 10 from 100 columns have updated. I want to which 10 columns have been updated.

How to do it with triggers?

Or there is any other way than triggers like, in Cassandra, inserting using same PK will act as an update for a row.

score 0 · Answer 1 · edited Mar 19 '21 at 12:08

0

If you have to do the update you can add a RETURN statement for show updated rows. You cn see more on the documentation of Postgres: https://www.postgresql.org/docs/current/dml-returning.html

edited Mar 19 '21 at 12:08

Frank Heikens

117,544
24
142
135

answered Mar 19 '21 at 10:06

Daniel Bistuer

52
3

Not After update, but before updating values, I want to check which which column values will differ from previous one. – R_S_C Mar 24 '21 at 05:01
I'll Edit my question to limit it to triggers – R_S_C Mar 24 '21 at 05:02

PostgreSQL trigger function to capture updated field

1 Answers1