There are lots of things to think about when you design a physical database. What data types should I use? What column is appropriate for the primary key? Are there particular indexes that I should use to improve performance? How should I implement data integrity rules? This list goes on and on. In this article Greg Larsen will be exploring different physical database design elements.  Read more...

Bad data always seems to appear when, and where, one least expects it. Sam explains the great value of a defensive approach based on constraints to any team that is developing an application in which the data has to be exactly right, and where bad data could cause consequential severe financial damage. It is perhaps better seen as creating a test-driven database.  Read more...

In the final step of Database Design, Joe Celko gives a simple but effective explanation of the normalization process and why it is important.  Read more...

This level of the stairway details the creation of a relational database, as well as filling in some of the history of the relational database model.  Read more...

This final level to the first landing completes the basics of a SQL database, by explaining what cursors are and why you should never use them.   Read more...

On Thursday October 20th ,MVP Louis Davidson will discuss the why normalized databases are the most important part of query tuning  Read more...

In levels one to four, we built the tables, base and virtual, of a schema. Levels five and six dealt with stored procedures. This level deals with a feature you need to avoid as much as possible; this is article is on Triggers.  Read more...

Having covered the procedure headers in SQL Server in the previous level, Joe tackles the subject of the contents of stored procedures. In this level, he outlines limitations of TSQL as a procedural language, and what you need to bear in mind when deciding how to use them.  Read more...

GUIDs are often regarded as a necessary evil but how necessary are they?  Read more...

The third article in our series on normalization from Tom Thomson continues with an explanation on what constitutes third normal form.  Read more...

There is a popular design for a database that requires a built-in audit-trail of amendments and additions, where data is never deleted, but superseded by a later version. Whilst this is conceptually simple, it has always made reporting the latest version of data complicated. Alex Kuznetsov joins the debate on the best way of doing this with an example using an indexed view and the filtered index.  Read more...

In this article Tom Thomson takes a look at what second normal form means, how it is violated, and how you can fix it. This is part of our normalization series.  Read more...

Learn the basics of first normal form and what that means to a database designer from Tom Thomson.  Read more...

Identifiers aren't locators, and they aren't pointers or links either. They are a logical concept in a relational database, and, unlike the more traditional methods of accessing data, don't derive from the way that data gets stored. Identifiers uniquely identify members of the set, and it should be possible to validate and verify them. Celko somehow involves watches and taxi cabs to illustrate the point.  Read more...

A great deal of the confusion that occurs when a database application is developed comes from a poor understanding of the basics of data. Here, Joe Celko gives a broad coverage of the difficulties you're likely to meet when handling data in databases  Read more...

When Agile meets 'Big Design', the result can be frustration on both sides. Is it possible for database development to to easily coexist with Agile methodologies for application development? Nick suggests that the technical solutions already exist, and the dissonance is more due to cultural and organizational problems  Read more...

An interesting mystery on why some nHibernate performance issues might exist on your systems. Read this piece from SQL Server expert David Poole and look to see if this is a problem you can easily solve in your environment.  Read more...

I’ve explained the database design process in a series of articles that you can find here. In this tutorial, I’ll put that information to good use and design a database from the start of the process to the finish. To keep this example to a single article, I’ll not repeat the information from those previous articles, so make sure you look those over before reading this one.  Read more...

Once, when disk space was at a premium, DBAs fought hard to keep the size of their database down. Now there seems less motivation to 'fight the flab' of a database. Fabiano Amorim was watching television recently when the subject matter, cosmetic surgery, gave him the theme and inspiration for this guide to keeping your database fit and trim.  Read more...

Lookup tables can be a force for good in a relational database. Whereas the 'One True Lookup Table' remains a classic of bad database design, an auxiliary table that holds static data, and is used to lookup values, still has powerful magic. Joe Celko explains....   Read more...