Free has many connotations, depending upon where it is used. Free gas? Always a good thing. Free milk? Great (unless you're lactose intolerant). But free software? The first thought that comes to mind is, "What's the catch?" Microsoft® SQL Server® 2008 Express is free, which might cause people to have certain expectations around it. One of the obvious ones is that it will compare well to other free database systems like MySQL, which it does. The problem lies in the comparison criteria. A fair comparison is possible, but you have to be careful not compare apples and oranges.

Comparing a full-versioned, open source system to a feature-restricted version of a larger product is most likely a flawed process from the beginning—especially when the comparison's purpose is meant to compare the cons with one product against the pros of the other. That said, let's discuss SQL Server 2008 Express: what it is and how it should be utilized. Along the way, I will do some comparison to MySQL in order to provide more meat to the discussion.

The Truth: SQL Express 2008 Is What It Is
SQL Server 2008 Express is not a fully-featured version. Call it "free", but with limitations. It is not an open source database and it is not necessarily intended to compete with full-featured open source databases.

SQL Server 2008 Express (SQL Express 2008) is the entry-level version of the SQL Server product line that Microsoft offers free of charge. Their hope is to provide an easy-to-use database for learning and building small server applications while also providing a seamless upgrade path.

Having said all this, SQL Express 2008 is a solid database intended for real-world applications. Its feature-set includes arguably all the features you need to for basic data needs: data storage, stored procedures, triggers, views, etc. In addition, SQL Express 2008 provides most of the security and manageability features available in the full version of SQL Server.

The main caveat is that these features come with a cost...built-in performance limitations. Microsoft placed the following limits on SQL Express 2008:

• CPUs: Only 1 CPU. If a system has more than 1 SQL Express 2008 will still run but limit itself to 1 CPU.



• RAM: 1 GB. More RAM can exist, but again SQL Express 2008 will only make use of a maximum 1 GB.



• Database Size: 4 GB. This limitation provides for the storage of a considerable amount of data while protecting the domain of the higher-end SQL Server versions.

SQL Server Express Features SQL Server 2008 Express builds on the feature set included in SQL Server 2005 Express. As of this writing, a full listing of the 2008 feature set is not available at Microsoft.com. All the details do live out in the Internet however. For SQL Server 2005 Express's features list visit this link. For a list of new features included in SQL Server 2008 Express, visit this link. Together, these two sites provide the full feature listing for 2008.

Scenarios exist that are a good fit for SQL Express 2008 (and several that are not). For the most part, if you can live with the limitations imposed on SQL Express 2008, you are good to go. Just don't try to do something SQL Express 2008 was not architected to support. Some good scenarios for SQL Express 2008 are:

• Startups: When cash is tight it's best to hold onto the cash you have. For startups looking to build with the Microsoft platform, SQL Express 2008 is a good choice.



• Department-level application: Any situation where the expected user base is 20 users or less will be served well by SQL Express 2008. Small businesses, departments within large corporations, etc. It's the size of the user base that matters here.



• Prototyping and Learning: SQL Express 2008 works well for prototyping applications that will eventually work with a higher-end version of SQL Server. Developers can test architecture strategy and learn the SQL feature set. The work done prototyping is then useful when upgrading.

Given the performance limitations, using SQL Express 2008 for applications that must scale or maintain a high-degree of performance is not a good idea. The lack of memory and CPU will greatly impact the application's execution. Some examples of scenarios that are not suitable are:

• Enterprise-Level applications



• Memory intensive applications

So SQL Server Express is what it is. It's a solid entry-level database designed to let you "download and go" without any need to worry about licensing because it is free. It also provides the SQL Server Management Studio; a tool that allows you to manage the database from a graphical user interface. Last of all, the core SQL Server engine is there for you basic data management needs.