Aclient is any component of a system that requests services or resources from other system components.

A server is any system component that provides services or resources to other system components.

For example, when you print a document from your workstation on a network, the workstation is the client and the print spooling machine is the server.

In a client/server model, the database server is responsable for the following:

• Processing data modification and retrieval requests.
• Performing data-intensive processing.
• Enforcing all database rules and constrains.
• Enforcing data security.

In a client/server model, the database client is responsable for the following:

• Presenting the data to the user in an easily and useful format.
• Providing an interface to the various tools, data, and reports.
• Submitting requests to the server.

SQL Server helps you build, deploy, and manage enterprise applications. At the center of SQL Server is the SQL Server engine, which processes the database commands. The process runs inside Windows and understands only connections and SQL commands.