Statement interface

In this chapter you will learn:

Create and use Statement Object
Execute SQL Statements
Closing Statement Obeject

Creating Statement Object

We can use the Connection object's createStatement() method to create an object of Statement.

The following code shows a general structure of using Statement

Statement stmt = null;//java 2  s .  com
try {
   stmt = conn.createStatement( );
   stmt.executeUpdate(...);
   . . .
}
catch (SQLException e) {
   . . .
}
finally {
   . . .
   
}

Execute SQL Statements

Once we have the Statement object, we can execute a SQL statement with one of its three execute methods.

boolean execute(String SQL) Returns a boolean value of true if ResultSet is ready.
int executeUpdate(String SQL) Returns the numbers of rows changed by the SQL statement. We usually use this method for INSERT, UPDATE, or DELETE statement.
ResultSet executeQuery(String SQL) Returns a ResultSet object. We usually use this method for a SELECT statement.

Closing Statement Obeject

After using the Statement object we have to close the Statement object by calling the close() method.

Statement stmt = null;/*from j a  va 2  s . c  o m*/
try {
   stmt = conn.createStatement( );
   . . .
}
catch (SQLException e) {
   . . .
}
finally {
   stmt.close();
}