How to use prepared statements for more efficient access

If you use the Statement interface, you parse each statement that you send to the database, generate an access plan, and execute the statement. The steps before execution are called preparing the statement.

You can achieve performance benefits if you use the PreparedStatement interface. This allows you to prepare a statement using placeholders, and then assign values to the placeholders when executing the statement.

Using prepared statements is particularly useful when carrying out many similar actions, such as inserting many rows.

Example

The following example illustrates how to use the PreparedStatement interface, although inserting a single row is not a good use of prepared statements.

The following InsertDynamic method of the JDBCExample class carries out a prepared statement:

public static void InsertDynamic( Connection con,
              String ID, String name )
{
  try 
  {
    // Build the INSERT statement
    // ? is a placeholder character
    String sqlStr = "INSERT INTO Departments " +
            "( DepartmentID, DepartmentName ) " +
            "VALUES ( ? , ? )";

    // Prepare the statement
    PreparedStatement stmt =
      con.prepareStatement( sqlStr );

    // Set some values
    int idValue = Integer.valueOf( ID );
    stmt.setInt( 1, idValue );
    stmt.setString( 2, name );

    // Execute the statement
    int iRows = stmt.executeUpdate();

    // Print the number of rows inserted
    System.out.println(iRows + " rows inserted");
  }
  catch (SQLException sqe)
  {
    System.out.println("Unexpected exception : " +
              sqe.toString() + ", sqlstate = " +
              sqe.getSQLState());
  }
  catch (Exception e)
  {
    e.printStackTrace();
  }
}

Notes

This code fragment is part of the JDBCExample.java file included in the %SQLANYSAMP16%\SQLAnywhere\JDBC directory.
The executeUpdate method returns an integer that reflects the number of rows affected by the operation. In this case, a successful INSERT would return a value of one (1).
When run as a server-side class, the output from System.out.println goes to the database server messages window.

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