JDBC CS DDL statements with execute .
How to do SQL DDL Statements with the execute() method existing in the CallableStatement Object?
- First you need to Create a Database Connection.
- With a DB connection, you must write the SQL statement and let this statement be the parameter to the below specified prepareCall() method.
- The SQL statement must do a call to a database stored procedure that do a SQL Update into a database table.
- If you have any parametric placeholders for values in your SQL statement, then it is time to set these using the PreparedStatement setXXX() methods.
- If any parametric placeholder exists in your SQL statement which can result in an output from the database-stored procedure or function you want to call, then it is time to set the type for these using the CallableStatement registerOutPutParameter() methods.
-
Now you can create a CallableStatment object with the method:
Methods in Connection interface Description CallableStatement prepareCall(String sql) Creates a CallableStatement object for calling database-stored procedures. -
With the returned CallableStatement object, you can execute the following
method to perform the SQL Update statement:
Method in CallableStatement interface Description boolean execute() Executes the SQL procedure call statement in this CallableStatement object. The database procedure or function may be contain any kind of SQL statement. -
The CallableStatement object will now contain
requested database data, which can be retrieved with the
getXXX() methods.
Example of using this method to use SQL DDL statement:
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.CallableStatement; public class SQLAlter { public static void main(String[] args) { Connection conn = null; CallableStatement stmt = null; try { // Register a driver for the MySQL database Class.forName("com.mysql.jdbc.Driver"); // Create a url for accessing the MySQL // database CarDB String url = "jdbc:mysql://localhost:3306/CarDB"; // user and password to access the database String username = "root"; String password = "root"; // User the DriverManager to get a Connection to the database conn = DriverManager.getConnection(url, username, password); /* --- USING DB Defined PROCEDURE: UpdateCarRental() ------ DELIMITER $$ DROP PROCEDURE IF EXISTS `cardb`.`UpdateCarRental`$$ CREATE DEFINER=`root`@`localhost` PROCEDURE `UpdateCarRental`() BEGIN ALTER TABLE CARRENTAL ADD COLUMN TotalCost numeric; COMMIT; Update CARRENTAL r set TotalCost=RENTALDAYS* (Select c.dayPrice from CARPARK c where c.RegNO=r.RegNO); END$$ DELIMITER ; ------------------------------------------------- */ // Create a CallableStatement with a SQL that // add a Column, TotalCost, // to the CARRENTAL Table // Updates the new Column, TotalCost, // to be the cost for each rental of the cars. stmt = conn.prepareCall("{ call UpdateCarRental() }"); // Executing the SQL with CallableStatement object // execute() method boolean result = stmt.execute(); /* --- USING DB Defined PROCEDURE: getCarRental() ------ DELIMITER $$ DROP PROCEDURE IF EXISTS `cardb`.`getCarRental`$$ CREATE DEFINER=`root`@`localhost` PROCEDURE `getCarRental`(IN pId varchar(5)) BEGIN select * from Carpark c, CARRENTAL r where c.REGNO=r.REGNO AND r.CARRENTAL_ID LIKE pId; END$$ DELIMITER ; ----------------------------------------------------- */ // Create a ResultSet with a query that returns // all the columns from the dB table Carpark // using the execute() method on the CallableStatement object stmt = conn.prepareCall("{ call getCarRental('%') }"); result = stmt.execute(); ResultSet resultSet = null; // if result true it is a ResultSet if (result) { resultSet = stmt.getResultSet(); } // As cursor is at the before first row position // we use the next() method to // test and read the first row in the ResultSet. if (resultSet.next()) { // Then we use a loop to retrieve rows and column data // and creates a html coded table output System.out.println("<table border='1' >"); System.out.println("<tr>"); System.out.print("<th>regNo</th>"); System.out.println("<th>cartype</th>"); System.out.println("<th>model</th>"); System.out.println("<th>day<br/>Price</th>"); System.out.println("<th>Cost</th>"); System.out.println("</tr>"); do { System.out.println("<tr>"); System.out.print("<td>" + resultSet.getString("regNo") + "</td>"); System.out.println("<td>" + resultSet.getString("cartype") + "</td>"); System.out.println("<td>" + resultSet.getInt("model") + "</td>"); System.out.println("<td>" + resultSet.getDouble("dayPrice") + "</td>"); System.out.println("<td>" + resultSet.getDouble("TotalCost") + "</td>"); System.out.println("</tr>"); } while (resultSet.next()); System.out.println("</table>"); } } catch (ClassNotFoundException ex) { ex.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { try { // Close the Statement, which also close the ResultSet stmt.close(); conn.close(); } catch (Exception xe) { xe.printStackTrace(); } } } }
You should use the close() method in the Statement object when you do not need it anymore.
You should also use the close() method in the Connection object when you do not need it anymore.
You can download this example here (needed tools can be found in the right menu on this page).
If we run this application the result should be:As pure output Translated by a Browser <table border='1' > <tr> <th>regNo</th><th>cartype</th> <th>model</th> <th>day<br/>Price</th> <th>Cost</th> </tr> <tr> <td>DE12345</td><td>AUDI</td> <td>2003</td> <td>250.0</td> <td>1250.0</td> </tr> <tr> <td>DE12345</td><td>AUDI</td> <td>2003</td> <td>250.0</td> <td>750.0</td> </tr> <tr> <td>RE23456</td><td>FORD</td> <td>2005</td> <td>350.0</td> <td>2450.0</td> </tr> <tr> <td>RE23456</td><td>FORD</td> <td>2005</td> <td>350.0</td> <td>1750.0</td> </tr> <tr> <td>CE23473</td><td>AUDI</td> <td>2001</td> <td>400.0</td> <td>1600.0</td> </tr> <tr> <td>DE34562</td><td>OPEL</td> <td>2001</td> <td>340.0</td> <td>1020.0</td> </tr> <tr> <td>DE34562</td><td>OPEL</td> <td>2001</td> <td>340.0</td> <td>1700.0</td> </tr> </table>
regNo cartype model day
PriceCost DE12345 AUDI 2003 250.0 1250.0 DE12345 AUDI 2003 250.0 750.0 RE23456 FORD 2005 350.0 2450.0 RE23456 FORD 2005 350.0 1750.0 CE23473 AUDI 2001 400.0 1600.0 DE34562 OPEL 2001 340.0 1020.0 DE34562 OPEL 2001 340.0 1700.0
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