Get result from select exists, execute insert query based on the response of it

Question

I have to insert unique value for a row but has to put check on 3 columns collectively ((unique value(col1 && col2 && col3) == true)

I found a solution here it is

query = select exists(select 1 from titles where "col1"='${col1}' AND "col2"='${col2}' AND "col3"='${col3}');

This query would return true or false based on the entries of the table

if(query == true)

execute insert into table values ('col1','col2','col3','col4','col5');

I am inserting multiple records from a json file using promises.

Is there any way to execute this in single sequelize.query().

Answer 1

Create a UNIQUE index or constraint on (col1, col2, col3) - if you don't have one already.

Then use INSERT ... ON CONFLICT ... DO NOTHING. That's simpler, faster and more reliable, and unlike the route you had in mind, it's also safe against race conditions.

Related:

• What does a CONSTRAINT have to do with my unique index?
• What happens with duplicates when inserting multiple rows?

Be aware of NULL handling:

• PostgreSQL multi-column unique constraint and NULL values