Unique

Postgres unique constraint

By Franck Pachot . I'll start a series on Postgres vs. Oracle access paths because I know Oracle and I learn Postgres. While preparing it, I came upon some surprises because I'm so used to Oracle(…)

Nulls in composite keys

By Franck Pachot . Comparison of NULL can be misleading and it's even worse for unique constraint validation. Having partial nulls in a composite key can be tricky because the SQL ANSI specification is not very easy to understand, and(…)