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Building Scalable and High-Performance Java™ Web Applications Using J2EE™ Technology by Greg Barish

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Querying a Database

Let's take a quick break to discuss how a database can be queried. In this section, we'll cover basic SQL as well as what's involved in single-table and multitable querying. This will not only make the next section easier to understand, but it will help categorize the queries that we'll refer to later.

Querying Data

Clients interact with DBMSs by issuing queries. To query means to inquire, so, it's no surprise that queries is the database term used to refer to the retrieval of data. However, when talking about databases, query also applies to the inserting, updating, and deleting of data as well as to the creation, alteration, and destruction of database objects (such as tables). To issue a query to a database means to express ...

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