The execute( ) Method

The execute( )
method is the most generic method you
can use to execute a SQL statement in JDBC. To execute a
SQL statement with the execute method,
call it by passing it a valid SQL statement as a
String object, or as a string literal, as shown in
the following example:

boolean isResultSet = false;
Statement stmt = null;
try {
  stmt = conn.createStatement(  );
  isResultSet = stmt.execute("select 'Hello '||USER from dual"); 
  . . . 
}

In this example, we assume that Connection object
conn already exists. First, a
boolean variable named
isResultSet is created to hold the return value
from the call to the execute( ) method. Next, a
variable named stmt is created to hold a reference
to the Statement object. In the
try block, the Statement object
is created with a call to the Connection
object’s createStatement( ) method. Then,
the Statement object’s execute( ) method is called passing a SQL SELECT statement. Since
this is a SELECT statement, the execute( ) method
returns a boolean true to indicate that a result
set is available. You can then call the Statement
object’s getResultSet( ) method to retrieve
the ResultSet object that contains the data from
the database. For example:

boolean isResultSet = false;
Statement stmt = null;
ResultSet rslt = null;
try {
  stmt = conn.createStatement(  );
  isResultSet = stmt.execute("select 'Hello '||USER from dual"); 
  if (isResultSet) {
    rslt = stmt.getResultSet(  );
  }
  . . . 
}

We’ll cover result sets in great detail in Chapter 10.

If an INSERT, …