What is a foreign key? It’s a column that must match a key in another table, and SQL Server refuses any value that has no match. This post shows the error it raises, the ON DELETE options, and why the foreign key column needs an index of its own.
Rewriting OR Conditions So the Index Gets Used
Rewrite OR conditions with separate seeks, preserve duplicate and NULL behavior, and compare plans before choosing UNION or recompilation.
Sample Databases for Practicing Performance Tuning
Use sample databases for practicing performance tuning by checking data volume and skew, then enlarging the right tables carefully.
Rebuilding One Partition Online Instead of the Whole Index
A big partitioned table does not need a full index rebuild every night. Here is how to rebuild one partition safely.
TechEd India 2013 Bangalore and Pune: A Photo Journey
TechEd India 2013 Bangalore and Pune was my fifth TechEd and fourth as a speaker: four sessions in two cities, on performance troubleshooting and indexes, told in photos.
Overlapping Indexes With INCLUDE Columns: Merging Them Safely
Find overlapping indexes, compare ordered keys and INCLUDE lists, merge coverage carefully, and review usage before removing either index.
Does Column Order in CREATE TABLE Change How Rows Are Stored?
Someone wants to reorder columns to shrink rows. I measured it on SQL Server 2025, and the answer is mostly no, with one small exception worth knowing.