/* * This sample shows how to use the "define" extensions. * The define extensions allow the user to specify the types * under which to retrieve column data in a query.  * * This saves round-trips to the database (otherwise necessary to * gather information regarding the types in the select-list) and * conversions from native types to the types under which the user * will get the data. * * This can also be used to avoid streaming of long columns, by defining * them as CHAR or VARCHAR types. * * note: jdk1.2 is recommanded. jdk1.1 will also work */// You need to import the java.sql package to use JDBCimport java.sql.*;// You need to import oracle.jdbc.* in order to use the// API extensions.import oracle.jdbc.*;class DefineColumnType{  public static void main (String args [])       throws SQLException  {    // Load the Oracle JDBC driver    DriverManager.registerDriver( new oracle.jdbc.OracleDriver());    String url = "jdbc:oracle:oci8:@";    try {      String url1 = System.getProperty("JDBC_URL");      if (url1 != null)        url = url1;    } catch (Exception e) {      // If there is any security exception, ignore it    }    // Connect to the database    Connection conn =      DriverManager.getConnection (url, "hr", "hr");    Statement stmt = conn.createStatement ();    // Call DefineColumnType to specify that the column will be    // retrieved as a String to avoid conversion from NUMBER to String    // on the client side.  This also avoids a round-trip to the    // database to get the column type.    //    // There are 2 defineColumnType API.  We use the one with 3 arguments.    // The 3rd argument allows us to specify the maximum length    // of the String.  The values obtained for this column will    // not exceed this length.    ((OracleStatement)stmt).defineColumnType (1, Types.VARCHAR, 7);    ResultSet rset = stmt.executeQuery ("select employee_id from employees");    while (rset.next ())    {      System.out.println (rset.getString (1));    }    // Close the resultSet    rset.close();    // Close the statement    stmt.close ();     // Close the connection    conn.close();  }}