ArcGIS Desktop (ArcEditor and ArcInfo), ArcGIS Engine, and ArcGIS Server Workgroup come with an executable file that installs SQL Server Express and enables the SQL Server Express instance to store ArcSDE geodatabases.

These geodatabases use the ArcSDE direct connect libraries installed with the ArcGIS Desktop, ArcGIS Engine, or ArcIMS client to connect from the client application to the SQL Server Express database.

You must have administrative privileges on the computer on which you want to install SQL Server Express. Users with administrative privileges on the machine automatically have administrator privileges in the database server except when SQL Server Express is installed on a machine with a Windows Vista or Windows 2008 Server operating system. During installation, a database server administrator can be added to the instance.

By default, SQL Server Express uses up to 1 GB of memory. It relinquishes memory as other applications request it. That means, if you only have 1 GB of memory on the computer on which SQL Server Express and ArcGIS Desktop or ArcGIS Server Workgroup are installed, you might encounter slower performance. If you find this to be true, you might want to increase the amount of random access memory (RAM) on the computer.

Installation for ArcSDE for SQL Server Express is a two-step process:

1. Install Microsoft SQL Server Express Edition with Advanced Services.
The setup program installs the Microsoft Windows Installer, if required, and checks the computer for Microsoft .NET Framework 2.0 before continuing with the Microsoft SQL Server Express with Advanced Services installation. If you do not have Microsoft .NET Framework 2.0 installed on your computer, the setup program closes. You can download .NET Framework 2.0 from the Microsoft site. Once it is installed, rerun the SQL Server Express with Advanced Services installation.
Use the installation wizard to install SQL Server Express. Be sure to read the installation guide provided in the ArcGIS Desktop, ArcGIS Engine, or ArcGIS Server Workgroup media for instructions on what settings to use in the wizard.
You will have an instance of SQL Server Express with Advanced Services running on the computer when you finish the installation. This instance is referred to as an ArcSDE database server in ArcGIS Desktop.
2. Continue with the wizard to complete the postinstallation setup. This will configure the SQL Server Express instance to use ArcSDE geodatabases, add an administrative user to the database server, authorize the software (ArcGIS Server Workgroup only), and configure SQL Server Express to support remote connections.
Be aware that on Vista and Windows 2008 Server machines, you must add an administrative user during the postinstallation setup. Initially, the administrative user you add during postinstallation will be the only user who can perform such tasks as creating geodatabases and adding other users to the database server. Unlike SQL Server instances on Windows XP and 2003 Server machines, which automatically assign Windows administrators to be administrators in the SQL Server instance, SQL Server instances on Vista or Windows 2008 Server do not by default give Windows administrators sysadmin privileges. This behavior on Vista and Windows is enforced by User Access Control (UAC). Turning off UAC will cause Vista and Windows 2008 Server to behave like XP and Windows 2003 Server.
Each server machine on which the workgroup database server is installed requires an authorization file. To obtain this, contact your ESRI representative.

For complete installation instructions, consult the installation guide provided with the ArcGIS Desktop, ArcGIS Engine, or ArcGIS Server Workgroup media.

At this point, no geodatabases have been created; you just have an instance of SQL Server Express that is ready to store ArcSDE geodatabases. Your next step is to add the database server to the Catalog tree. Similar to adding a mapped drive for file-based data or adding a database connection for ArcSDE geodatabases, you must do this for every connecting client that needs to administer the database server or the geodatabases stored on it.

To learn how to add a database server to ArcCatalog, see Adding an ArcSDE database server.

Tips A list of the prerequisite software and minimum and recommended hardware and software requirements for running Microsoft SQL Server Express with Advanced Services can be found at the Microsoft support site: http://support.microsoft.com/kb/910229/en-us There currently is neither a 64-bit version of SQL Server 2005 Express with Advanced Services nor a 64-bit version of ArcGIS Desktop; however, both run on certain 64-bit computers. For SQL Server Express on a 64-bit computer, you need the 64-bit version of .NET Framework 2.0. For details on supported platforms and requirements for SQL Server Express, consult the Microsoft support site. For information on supported platforms for ArcGIS Desktop, see the ESRI support site.