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About recordsets

Web pages can’t directly access the data stored in a database. Instead, they interact with a recordset. A recordset is a subset of the information (records), extracted from the database using a database query. A query is a search statement designed to find and extract specific information from a database.

When using a database as a content source for a dynamic web page, you must first create a recordset in which to store the retrieved data. Recordsets serve as an intermediary between the database storing the content and the application server generating the page. Recordsets are temporarily stored in the application server’s memory for faster data retrieval. The server discards the recordset when it is no longer needed.

A 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.

Database queries are written in Structured Query Language (SQL, pronounced “sequel”), a simple language that allows you to retrieve, add, and delete data to and from a database. The SQL builder included with Dreamweaver lets you create simple queries without having to understand SQL. However, if you want to create complex SQL queries, a basic knowledge of this language lets you create more advanced queries, and provides you with greater flexibility in designing dynamic pages.

Before you define a recordset for use with Dreamweaver, you must create a connection to a database and—if no data exists yet—enter data into the database. If you have not yet defined a database connection for your site, refer to the database connection chapter for the server technology you are developing for, and follow the instructions on creating a database connection.