Welcome to Microsoft SQL Server

Overview of Client/Server Client/server is a style of computing where a client process requests services from a server process. In the simplest terms, a server is a program that makes available any kind of service, such as e-mail, files, ftp, Web, or data in the form of a database server. A client is an application that connects to a server to make use of the service it provides. Clients and servers have different jobs. Some examples of server responsibilities are providing backups to ensure data is safe, security against unwanted intrusion, timely access to the service, and maintenance of reliable storage facilities to ensure high availability of the service. Some examples of client responsibilities are providing a pleasing user interface, making use of the limited server resources in a responsible and resource-economical way, and, of course, fulfilling the goals of the application. Client applications include mail clients, such as Eudora and Microsoft Outlook. These applications connect to a mail server to retrieve e-mail messages. Internet Explorer is a client that connects to a Web server. SQL Server client applications that ship with the product include the Query Analyzer, SQL Server Enterprise Manager, Profiler, SQL Agent, and even Data Transformation Services. Each of these applications connects to the database engine and uses the engine's services in a different way. To use the service, each of these clients sends a query to the server. The server processes the query and sends back results.

SQL Server 2000 Components and Features SQL Server 2000 is more than just the database engine. While the database engine is at the core of the product, and obviously the most important component, there are a number of additional applications bundled with the database engine, such as the tools and utilities used to manage the SQL Server environment, as well as other components and server applications that extend the capabilities and features of SQL Server 2000. This section provides an overview of the components and features that are included with the SQL Server 2000 product. Each of these components is subsequently explored in greater detail in the rest of this book. SQL Server Database Engine SQL Server's database engine is the primary server application in the SQL Server package. Following are the main responsibilities of the database engine: Provide reliable storage for data sent to the engine Provide a means to rapidly access this data Provide consistent access to the data Control access to the data through security Enforce data-integrity rules to ensure the data is accurate and consistent Each of these points will be examined in detail later in the book. I will touch on each of these points to show how Microsoft SQL Server fulfills these core responsibilities.

SQL Server 2000 Environments

SQL Server, in addition to being available in a number of editions, also runs on a number of Windows platforms. However, certain editions will only run on certain platforms. This section takes a look at the platforms on which SQL Server runs and the editions it supports.

Windows 98 and Windows Me

Windows 98 and Windows Me are designed primarily for the home PC user. Windows 98 is still in use on the desktop in many corporate shops as well. Windows 98 and Windows Me are intended to support mobile users who are disconnected from the network but need to run applications that require SQL Server data storage, or for users who need to run local applications that require local SQL Server data storage on the computer.

For these purposes, the Windows 98 and Windows Me platforms support the SQL Server 2000 Standard Edition and the SQL Server 2000 Desktop Engine. Although the Full Text Search and Analysis Services are included with the Personal Edition of SQL Server, they cannot be installed on Windows 98 or Windows Me. Also, because Windows 98 and Windows Me do not support applications running as services, SQL Server and SQL Task Manager run as standard executables on Windows 98 and Windows Me rather than as services, as they do under Windows NT or Windows 2000.

The Windows 98 and Windows Me environments also support the installation of the SQL Server client tools, such as Query Analyzer, Enterprise Manager, and SQL Profiler. The connectivity components needed to connect to any SQL Server 2000 edition running on a Windows NT or Windows 2000 workstation or server can be installed on Windows 98, Windows Me, or Windows 95.

SQL Server 2000 Editions

You can choose from several editions of SQL Server 2000. The edition you choose will depend on your database and data processing needs, as well as the Windows platform on which you want to install it.

For actual deployment of SQL Server in a live deployed server environment, you can only choose from two editions of SQL Server: Standard Edition and Enterprise Edition. In addition, SQL Server also is available for special uses in a Developer Edition, Personal Edition, Desktop Engine Edition, or Windows CE Edition.

This chapter will examine the different editions of SQL Server and discuss their features and capabilities. Using this information, you will be better able to choose which edition provides the appropriate solution.

SQL Server 2000 Standard Edition

The Standard Edition of SQL Server 2000 is the version intended for the masses—those running small- to medium-sized systems that don't require the performance, scalability, and availability provided by Enterprise Edition. The Standard Edition runs on any of the Windows 2000 or Windows NT 4.0 Server platforms with scalability limited to up to four processors and 2GB of memory. Standard Edition includes the following features:

• Analysis Services

• Data Transformation Services

• Full Text Search

• English Query

• Built-in XML support

• SQL Profiler and performance analysis tools

• Graphical DBA and Developer tools

• Replication

• Data mining tools

SQL Server Licensing Models

In addition to feature sets, one of the determining factors in choosing a SQL Server version is cost. With SQL Server 2000, Microsoft has changed the licensing model to include a processor-based licensing model intended for Web-based environments in which the number of clients or user connections is indeterminate.

Processor licensing requires a single license for each central CPU in the machine running a Microsoft Server product. This type of license includes unlimited client device access. Additional server licenses, seat licenses, and Internet connector licenses are not required. You must purchase a processor license for each installed processor on the server on which SQL Server 2000 will be installed even if some processors will not be used for running SQL Server. The only exception is for systems with 16 or more processors that allow partitioning the processors into groups so the SQL Server software can be delegated to a subset of the processors.

For those who prefer the more familiar Server/Per-Seat Client Access License (CAL), or for those environments in which the number of client devices connecting to SQL Server is known, server or CAL-based licensing models are still available. This licensing model requires purchasing a license for the computer running SQL Server 2000, as well as a license for each client device that accesses any SQL Server 2000 installation. A fixed number of CALs are included with a server license and the server software. Additional CALs can be purchased as needed.

Server/Per Seat CAL licensing is ideal for those environments in which the number of clients per server is relatively low, and access from outside the firewall is not required. Be aware that using a middle tier or transaction server that pools or multiplexes database connections does not reduce the number of CALs required. A CAL is still required for each distinct client workstation that connects through the middle tier. (Processor licensing might be preferable in these environments due to its simplicity and affordability when the number of clients is unknown and potentially large.)