Tagged Questions
3
votes
2answers
46 views
checksum(newid()) as primary key - what happens if a collision occurs?
Inspecting a rather critical database that is used by some software on my system, I found that one of the tables had a primary key on the column Id, where Id is calculated using checksum(newid()). ...
3
votes
1answer
88 views
Should I always make an attribute id that's an primary key?
I was thinking, sometimes several columns in a table uniquely specify the whole row.
In that case, is there a need to create a special column for a primary key?
Is that good for something?
4
votes
2answers
131 views
What happens to the index of a primary key after a DROP CONSTRAINT?
I am running PostgreSQL 9.1.4.
I have a table with many existing rows, and a bunch of other tables with foreign keys pointing to it, for which I am trying to :
1 - Remove the pkey constraint on the ...
5
votes
3answers
703 views
Differences between “Unique Key” and “Primary Key”
What are the major differences between Unique Key and Primary Key in MySQL?
2
votes
4answers
567 views
Two-sided UNIQUE INDEX for two columns
Creating a table with composite PRIMARY KEY or using UNIQUE INDEX for two columns guarantee uniqueness of col1, col2. Is there a tricky approach to make the reverse order of two columns UNIQUE too ...
7
votes
4answers
245 views
What are the performance considerations between using a broad PK vs a separate synthetic key and UQ?
I have several tables where records can be uniquely identified with several broad business fields. In the past, I've used these fields as a PK, with these benefits in mind:
Simplicity; there are no ...
