Interacting with Networks and Databases - Beginning Java 7 - page 865

java.sql.SQLTransientException -rooted class hierarchies, where
SQLNonTransientException describes failed operations that cannot be retried
without changing application source code or some aspect of the data source, and
SQLTransientException describes failed operations that can be retried immedi-
ately.
Statements
After obtaining a connection to a data source, an application interacts with the data
source by issuing SQL statements (e.g., CREATE TABLE , INSERT , SELECT ,
UPDATE , DELETE , and DROP TABLE ). JDBC supports SQL statements via the
java.sql.Statement , java.sql.PreparedStatement , and
java.sql.CallableStatement interfaces. Furthermore, Connection de-
clares various createStatement() , prepareStatement , and pre-
pareCall() methods that return Statement , PreparedStatement , or
CallableStatement implementation instances, respectively.
Statement and ResultSet
Statement istheeasiest-to-useinterface,and Connection 's Statement cre-
ateStatement() methodistheeasiest-to-usemethodforobtaininga Statement
instance.Aftercallingthismethod,youcanexecutevariousSQLstatementsbyinvok-
ing Statement methods such as the following:
• ResultSet executeQuery(String sql) executes a SELECT state-
mentand(assumingnoexceptionisthrown)providesaccesstoitsresultsviaa
java.sql.ResultSet instance.
• int executeUpdate(String sql) executes a CREATE TABLE ,
INSERT , UPDATE , DELETE , or DROP TABLE statement and (assuming no
exceptionisthrown)typicallyreturnsthenumberoftablerowsaffectedbythis
statement.
I've created an EmployeeDB application that demonstrates these methods. Listing
9-17 presents its source code.
Listing 9-17. Creating, inserting values into, querying, and dropping an EMPLOYEES table
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;