Re:We Can Do Better Than SQL
by paulddraper on Friday May 10, 2019 @05:05AM
(#19876227)
> even CREATE INDEX is not part of any ANSI or ISO SQL specification
That's correct, and that's why PostgreSQL has ADD CONSTRAINT.
The constraints describe the actual schema of the data; INDEX is an DBMS-specific implementation* for improving performance (including index types, etc.).
* Those since the standard does not yet cover some thing partial unique constraints, these have to be done as INDEX in PostgreSQL.
That's correct, and that's why PostgreSQL has ADD CONSTRAINT.
The constraints describe the actual schema of the data; INDEX is an DBMS-specific implementation* for improving performance (including index types, etc.).
* Those since the standard does not yet cover some thing partial unique constraints, these have to be done as INDEX in PostgreSQL.