Can you have a nullable primary key? No. A primary key must not contain NULL: Allow Nulls cannot be set on its columns, and all values must be unique.
SQL SERVER – Trace Flags – DBCC TRACEON
Trace flags let a DBA turn a database function on or off for a while. How to use DBCC TRACEON and TRACEOFF, with deadlock trace flag 1205 as the example.
SQL SERVER – Fix : Error : Server: Msg 544, Level 16, State 1, Line 1 Cannot insert explicit value for identity column in table
Msg 544, cannot insert explicit value for identity column, happens when IDENTITY_INSERT is OFF. Turn it ON, insert your rows, then turn it OFF again.
Change Database Compatibility Level in SQL Server Safely
How to change database compatibility level in SQL Server 2025 with ALTER DATABASE. It covers the levels the server accepts, what the level changes in the optimizer, why single user mode isn’t needed, and a safe routine for raising the level with Query Store.
SQL SERVER – User Defined Functions (UDF) Limitations
Why are stored procedures more flexible? Here are the User Defined Functions (UDF) limitations: fewer input parameters, no GETDATE(), one result set, and more.
SQLAuthority News – Author Visit – Meeting with Readers – Top Three Features of SQL SERVER 2005
Over dinner in Las Vegas, two readers asked me to pick my top three features of SQL Server 2005 out of Microsoft’s top 30. Here is what I picked and why.
CTE Column Names: Rename Positions Without Moving Values
CTE column names rename positions without moving values. Compare inner aliases, report names and a misleading reversed list.