Accessing data stored in a database
Web pages cant directly access the data stored in a database. Instead, they interact with a recordset. A recordset is a subset of the information, or records, extracted from the database. This subset of information is extracted using a database query. A query is a search statement designed to find and extract specific information from a database. Dreamweaver uses the Structured Query Language (SQL) to build queries. Although you do not need to learn SQL (pronounced "sequel") to be able to create simple queries using Dreamweaver, a basic knowledge of this easy-to-understand language lets you create more advanced queries, and thus provides you with greater flexibility in designing dynamic pages. To learn the basics of SQL, see SQL Primer.
A SQL query can produce a recordset that includes only certain columns, only certain records, or a combination of both. A recordset can also include all the records and columns of a database table. However, because applications rarely need to use every piece of data in a database, you should strive to make your recordsets as small as possible. Because the web server temporarily holds the recordset in memory, using a smaller recordset uses less memory, and can potentially improve server performance.