MySQL™ and JSP™ Web Applications: Data-Driven Programming Using Tomcat and MySQL

Working with ResultSets

When you get a ResultSet back from a query, there are several ways to get at the data inside. You can refer to the columns positionally or by name. Let's look at a few code fragments to demonstrate the difference:

ResultSet rs = st.executeQuery("SELECT * FROM employees");

while (rs.next()) {
   String lname = rs.getString("lname_txt");
}

This example uses reference by name. You ask for column values by using the name of the column as an argument to the getX method:

ResultSet rs = st.executeQuery("SELECT lname_txt, fname_txt FROM employees");

while (rs.next()) {
   String lname = rs.getString(1);
}

This uses positional reference. The integer argument to getString refers to the position of the column in the list of columns ...