JDBC - Commit and Rollback Example
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Following is the example, which makes use of commit and rollback described in the Transaction tutorial.
This sample code has been written based on the environment and database setup done in the previous chapters.
Copy and past the following example in JDBCExample.java, compile and run as follows −
//STEP 1. Import required packages import java.sql.*; public class JDBCExample { // JDBC driver name and database URL static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; static final String DB_URL = "jdbc:mysql://localhost/EMP"; // Database credentials static final String USER = "username"; static final String PASS = "password"; public static void main(String[] args) { Connection conn = null; Statement stmt = null; try{ //STEP 2: Register JDBC driver Class.forName("com.mysql.jdbc.Driver"); //STEP 3: Open a connection System.out.println("Connecting to database..."); conn = DriverManager.getConnection(DB_URL,USER,PASS); //STEP 4: Set auto commit as false. conn.setAutoCommit(false); //STEP 5: Execute a query to create statment with // required arguments for RS example. System.out.println("Creating statement..."); stmt = conn.createStatement( ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); //STEP 6: INSERT a row into Employees table System.out.println("Inserting one row...."); String SQL = "INSERT INTO Employees " + "VALUES (106, 20, 'Rita', 'Tez')"; stmt.executeUpdate(SQL); //STEP 7: INSERT one more row into Employees table SQL = "INSERT INTO Employees " + "VALUES (107, 22, 'Sita', 'Singh')"; stmt.executeUpdate(SQL); //STEP 8: Commit data here. System.out.println("Commiting data here...."); conn.commit(); //STEP 9: Now list all the available records. String sql = "SELECT id, first, last, age FROM Employees"; ResultSet rs = stmt.executeQuery(sql); System.out.println("List result set for reference...."); printRs(rs); //STEP 10: Clean-up environment rs.close(); stmt.close(); conn.close(); }catch(SQLException se){ //Handle errors for JDBC se.printStackTrace(); // If there is an error then rollback the changes. System.out.println("Rolling back data here...."); try{ if(conn!=null) conn.rollback(); }catch(SQLException se2){ se2.printStackTrace(); }//end try }catch(Exception e){ //Handle errors for Class.forName e.printStackTrace(); }finally{ //finally block used to close resources try{ if(stmt!=null) stmt.close(); }catch(SQLException se2){ }// nothing we can do try{ if(conn!=null) conn.close(); }catch(SQLException se){ se.printStackTrace(); }//end finally try }//end try System.out.println("Goodbye!"); }//end main public static void printRs(ResultSet rs) throws SQLException{ //Ensure we start with first row rs.beforeFirst(); while(rs.next()){ //Retrieve by column name int id = rs.getInt("id"); int age = rs.getInt("age"); String first = rs.getString("first"); String last = rs.getString("last"); //Display values System.out.print("ID: " + id); System.out.print(", Age: " + age); System.out.print(", First: " + first); System.out.println(", Last: " + last); } System.out.println(); }//end printRs() }//end JDBCExample
Now let us compile the above example as follows −
C:\>javac JDBCExample.java C:\>
When you run JDBCExample, it produces the following result −
C:\>java JDBCExample Connecting to database... Creating statement... Inserting one row.... Commiting data here.... List result set for reference.... ID: 100, Age: 18, First: Zara, Last: Ali ID: 101, Age: 25, First: Mahnaz, Last: Fatma ID: 102, Age: 30, First: Zaid, Last: Khan ID: 103, Age: 28, First: Sumit, Last: Mittal ID: 106, Age: 20, First: Rita, Last: Tez ID: 107, Age: 22, First: Sita, Last: Singh Goodbye! C:\>
jdbc-transactions.htm
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