shows a program that connects to a database and then loops, prompting
the user for a SQL statement, sending that statement to the database,
and displaying the results. It demonstrates the four most important
techniques for JDBC programming: registering a database driver, using
DriverManager class to obtain a
Connection object that represents a
database connection, sending a SQL statement to the database using the
Statement object, and retrieving
the results of a query with a
ResultSet object. Before we look at the
specifics of the
program, let's examine these basic techniques.
One of the interesting things about the
java.sql package is that its most important
ResultSet—are interfaces instead of classes.
The whole point of JDBC is to hide the specifics of accessing
particular kinds of database systems, and these interfaces make that
possible. A JDBC driver is a set of classes that implement the
interfaces for a particular database system; different database
systems require different drivers. As an application programmer, you
don't have to worry about the implementation of these underlying
classes. All you have to worry about is writing code that uses the
methods defined by the various interfaces.
DriverManager class is responsible for keeping track of all the JDBC drivers that are available on a system. So the first task of a JDBC program is to register an appropriate driver for ...