Microsoft Access 2013 Tutorials
Database Design 101 / Understanding Normalization
Subtitles of the Movie (Microsoft Access 2013 / Database Design 101 / Understanding Normalization)
Normalization is a database term that you're going to hear a lot about if you new to this world and you're not going to understand it. Because it's kind of an abstract idea that until you kind of first get your head wrapped around the concept and then see it in action, it just kind of doesn't make sense. But once you see it and get it you kind of have it. Now first of all in this video I'm just going to kind of chalk talk here. I'm going to tell you what normalization is, talk about it just a little and then you'll see it in action in a number of different places through the course here. But normalization's one of those things that if I'm standing in front of a room of say 10,15 people and I explain it, six on side of the room and the other six are lost. And one of them will ask a question and so in answering their question those six get it and now you've confused the original six that had it. So normalization for some reason can be kind of tricky and it can be subjective. So it can be interesting especially when you get a number of database designers together. So exactly what is normalization? It is a systematic approach to the way we design our tables that ensures data integrity and efficiency. What we're really looking for here is to make sure that we aren't storing duplicate data, that we aren't storing empty space in our tables. That we're not repeating data, that we're making our tables easy to query from, to input and so forth. And understand that normalization affects both the way we store the data and the way we manipulate the data. Now manipulate the data means insert, updates and deletes as well as running queries and extracting data from our tables. Because this is going to determine the actual number of tables used and how they relate to each other. Now normalization is measured in stages. And the way these are referred to is as normal forms. There's a first normal form and you will see it called 1NF. There's a second normal form called 2NF and it just kind of keeps going there's a third, fourth, fifth, sixth, seventh and I think it goes up to like ten or twelve something like that. But you very seldom see it go that far. Now let's talk about what first normal form is. First normal form says that each field or column within a table should contain only one value. So you shouldn't put you know, you've got a column called book titles, you shouldn't put Atlas Shrugged comma Les Miserable comma and then some other book. Okay. So we should only have one single book title in a field or a column that's called book titles. So that's the first normal form. Then the table must not contain repeating groups of data. So to fix that problem what a lot of people would do is they would put in the table book title 1, book title 2, book title 3, book title 4, so you have four columns. But that doesn't solve the problem, it makes it even more complex for querying and that's called a repeating group of data so we don't do that. Second normal form after we've cleaned the first one up is that any data that's not primarily absolutely directly dependent on a table's composite primary key, gets moved to another table. And this is an example where we've got a primary key that's spread across three columns. And so you've got other columns in the table who really kind of apply to one of those keys but not to the other key. And if that makes sense to you, good if it don't don't worry about it. But the bottom line is, is we're going to continue to segregate our data so that everything in the table relates directly to the primary key. And the third normal form is once we start to split those composite primary keys out into individual column primary keys, then we're going to make sure that any data that does not directly relate to that primary key gets moved to it's own table with it's own primary key. Now is this confusing? Probably so. Just stick this stuff in your brain for right now and then we'll take a look at it a little more later and quite honestly it's a little more advanced than what we want to get into in this course. So I'm just kind of introducing it to you. Now there are more than three normal forms but they're seldom used. You know your really pointy head, really experienced database designers will use more than three forms but it's not a topic you really want to get into at this point. Again if you're having trouble sleeping at night get a book on normalization and get passed that third normal form and you'll be out in no time. So anyway that's just a little intro into normalization. That'll kind of help break the ice on this topic.
Tutorial Information
| Course: | Microsoft Access 2013 |
| Author: | Mark Long |
| SKU: | 34405 |
| ISBN: | 978-1-61866-090-9 |
| Release Date: | 2013-02-01 |
| Duration: | 7 hrs / 89 lessons |
| Work Files: |
Yes |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |
VTC Sign up & Benefits
- Unlimited Access
- 81,350 Video Tutorials (14,200 free)
- Video Available as Flash or QuickTime
- Over 715 Courses
- $30 for One Month Access
- Multi-User Discounts Available
