How many foreign key references can you have on a single table? I said 253 at SQLPASS, but my answer was not complete. Here is the full answer.
MySQL – Fix Error – WordPress Database Error Duplicate Entry for key PRIMARY for Query INSERT INTO wp_options
My blog was slow and scheduled posts failed. The cause was a Wordpress Database Error: duplicate entry for key PRIMARY in wp_options. Here is how I fixed it.
Finding Orphaned Child Rows Before Adding a Foreign Key
Find orphaned child rows before adding a foreign key, review their business meaning, validate relationships, and confirm constraint trust.
Does Dropping Primary Key Drop Non-Clustered Index on the Column? – Interview Question of the Week #085
Does dropping a primary key also drop the Non-Clustered Index on that column? An interview question with a small repro script to see the answer.
Database Sharding – How to Identify a Shard Key?
Picking the shard key is the hardest part of Database Sharding. Here are the guiding principles I shared at a user group for choosing a good one.
How to Drop Clustered Index on Primary Key Column? – Interview Question of the Week #084
DROP INDEX fails with Msg 3723 on a primary key. Here is how to drop clustered index on a primary key column the right way, through the constraint.
SQL SERVER – Installation Fails With Error – A Constraint Violation Occurred
SQL Server cluster Installation Fails with ‘A constraint violation occurred’ as the network name won’t come online. I’ve fixed it for 10 clients.