The Closed World Assumption Video by C. J. Date, O’Reilly Media Review
As a seasoned database professional and SQL Server MVP I was actually unaware of one of the most important notions of the [known to me] Relational Theory – The Closed World Assumption. I frankly speaking approached the opportunity to watch the video with a set of very low expectations, expecting to yawn soon and learn very little, boy how wrong I was!
I did feel like I am back to my late teens, sitting in the university, and it was a pleasant feeling, however C. J. Date did not sound [boring] like any of my university professors at all, it was a blast of useful, insightful information, every single second.
Indeed, the author comes from an enterprise (IBM), not the academia.
The pace of the video is fast, as it is action packed, but this way your every cent/penny is at work.
I admit, you will need to know a few terms as 3VLS – or get it known, but you will also need to understand the PK-FK principals, tuples and be very logical to extract the most benefits out of the video.
The part about data integrity – is the KEY! The piece on eliminating the NULLs is a GEM. Do NOT miss these two.
Sit, relax, be ready to pause and ponder, and enjoy the video, very much suggested to whoever builds relational databases.
Verdict: 5+ out of the possible 5. It’s an eye opener!
Disclaimer: this video was provided to me for free as part of the O’Reilly’s reader’s reviewer program.