Foreign Keys in SQL Server: What They Are and How to Use Them скачать в хорошем качестве

Foreign Keys in SQL Server: What They Are and How to Use Them

This video is part of LearnItFirst's Transact-SQL Programming: SQL Server 2008/R2 course. More information on this video and course is available here: http://www.learnitfirst.com/Course161 This is the first video in a two-video set on foreign keys. The foreign key is probably the most confusing of the constraint types, but the examples in these videos will help clarify what it's used for and how to use it. To demonstrate foreign keys, Scott uses a scenario in which users can recover a lost password with a password hint and answer. Highlights from this video: What is the purpose of foreign keys? Differences between primary keys and unique constraints Parent/child relationships Defining a "one to many" relationship and much more...