Inserts

concatenation

Hierarchies in SQL, Part II, the Sequel

In a followup to his first article on Hierarchies, Gus Gwynn takes a look at the performance of a few different methods of querying a hierarchy. Learn how the HierarchyID stacks up.

Basic of T-SQL

T-SQL Syntax

Table Variable

NULL

BIT Conversions

DATEADD function

Using DELETE CASCADE Option for Foreign Keys

Referential integrity is a very important thing to consider when designing a database. In my years as a DBA I've seen database designs that sit on both ends of the spectrum, none at all and cases where every table is linked to multiple tables. While the later certainly can be a little more difficult to work with it ensures the integrity of your data stays intact. The other end provides much more flexibility when it comes to updating and deleting data from your database, whether it's being done through the application or directly on the backend, but has the issue of possible orphan records if things are not done properly. This tip will look at the DELETE CASCADE option when creating foreign key constraints and how it helps keep the referential integrity of your database intact.