Chapter 10. Result Sets
As you saw in Chapter 9,
when you execute a SELECT statement, the results are returned as a
java.sql.ResultSet object. You’ll use the
functionality of the ResultSet object to scroll
through the set of results; work with the values returned from the
database; and make inserts, updates, and deletes. In this chapter,
we’ll start by covering the various data types that can be
accessed using JDBC, and then we’ll take a practical look at
their use while considering the data types available with Oracle.
Next, we’ll discuss the various ResultSet
accessor methods. We’ll continue by discussing how to handle
database NULL values in Java and spend much of the second half of the
chapter discussing scrollable and updateable result sets. Finally,
we’ll discuss the Oracle proprietary extensions to the
ResultSet object.
Basic Cursor Positioning
When you
use the Statement object’s
executeQuery( )
method to query the database with a SQL
SELECT statement, the Statement object returns a
ResultSet object. For the sake of brevity, the
returned ResultSet object contains the results of
your query.
In the database, your data is organized as rows of columns in a
table. Consequently, the result of a query against the database is a
result set that is also organized as rows of columns. A
ResultSet object provides a set of methods for
selecting a specific row in the result set and another set of methods
for getting the values of the columns in the selected row.
When a ResultSet object is ...
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