Express Technology Inc. software is designed to use Microsoft® SQL Server (all versions) for it's database engine. Smaller companies can use the ExpressEdition (MSDE) which is a scaled down version of SQL Server. Larger companies may desire or already have the complete SQL Server program. The following information about SQL is provided by Microsoft Corporation.
Microsoft® SQL Server™ is designed to be a client/server system. Client / Server systems are constructed so that the database can reside on a central computer, known as a server, and be shared among several users. When users want to access the data in SQL Server, they run an application on their local computer, known as a client, that connects over a network to the server running SQL Server.
Having data stored and managed in a central location offers several advantages:
•Each data item is stored in a central location where all users can work with it.
•Separate copies of the item are not stored on each client, which eliminates problems with users having to ensure they are all working with the same information.
•Business and security rules can be defined one time on the server and enforced equally among all users.
•A relational database server optimizes network traffic by returning only the data an application needs. For example, if an application working with a file server needs to display a list of the names of salesmen in Oregon, it must retrieve the entire employee file.
•Hardware costs can be minimized.
•Because the data is not stored on each client, clients do not have to dedicate disk space to storing data. The clients also do not need the processing capacity to manage data locally, and the server does not need to dedicate processing power to displaying data.
•The server can be configured to optimize the disk I/O capacities needed to retrieve data, and clients can be configured to optimize the formatting and display of data retrieved from the server.
•The server can be stored in a relatively secure location and equipped with devices such as an Uninterruptible Power Supply (UPS) more economically than fully protecting each client.
•Maintenance tasks such as backing up and restoring data are simplified because they can focus on the central server.
In large Client / Server systems, thousands of users may be connected to a SQL Server at the same time. SQL Server has full protection for these environments, with safeguards that prevent problems such as having multiple users trying to update the same piece of data at the same time. SQL Server also effectively allocates the available resources, such as memory, network bandwidth, and disk I/O, among the multiple users.
SQL Server applications can run on the same computer as SQL Server. The application connects to SQL Server using Windows Interprocess Communications (IPC) components, such as shared memory, instead of a network. This lets SQL Server be used on small systems where an application needs to store its data locally.
While SQL Server works very effectively as a server, it can also be used in applications that need a stand-alone database stored locally on the client. SQL Server can dynamically configure itself to run efficiently with the resources available on a client without the need to dedicate a database administrator to each client.