CSC System Development with Java. Database Connection. Department of Statistics and Computer Science. Budditha Hettige

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1 CSC System Development with Java Database Connection Budditha Hettige Department of Statistics and Computer Science Budditha Hettige 1

2 From database to Java There are many brands of database: Microsoft Access part of Microsoft Office MySQL very good, simple, open source Microsoft SQL Server robust and complex Oracle very robust and complex IBM DB2 enterprise robust and complex MySQL Database world's most popular open source database Budditha Hettige 2

3 Wamp Server for MySQL is an open source project, free to use (GPL licence) Allows you to create Web applications with Apache, PHP, and the MySQL database Manage your Apache and MySQL services Download from Tools PhpMyAdmin Budditha Hettige 3

4 Create a new Database Create a new database testdb Create a new table student Create table structure Budditha Hettige 4

5 Create table Structure Fields Id (Int, Primary) Name (varchar 25) Age (int) Budditha Hettige 5

6 Java Database Connectivity (JDBC) Sun Microsystems provided a common API to access a data source from a Java application. This is called the Java Database Connectivity (JDBC) JDBC is a set of classes and interfaces Download Budditha Hettige 6

7 Java Database Connectivity Architecture JAVA Application JDBC Driver Manager JDBC Driver1 JDBC Driver2 JDBC-ODBC Bridge ODBC Driver Data Source1 Data Source2 Data Source3 Budditha Hettige 7

8 JDBC API Import the java.sql package import java.sql.*; Firstly, you need to load the driver Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"). newinstance(); // loading the JDBC-ODBC bridge Then create a connection to the data source String url = jdbc:odbc:dbconn Connection c = DriverManager.getConnection(url, user", password"); Budditha Hettige 8

9 Sample Codes Create new MySQL Connection Insert new record Delete a record Update new record Show existing records Budditha Hettige 9

10 Database Connection // Manual connection for the localhost public Connection getconnection() throws Exception Connection conn = null; String driver = "com.mysql.jdbc.driver"; String url = "jdbc:mysql://localhost:3306/testdb"; String username = root"; String password = ""; Class.forName(driver); // load MySQL driver conn = DriverManager.getConnection(url, username, password); return conn; Budditha Hettige 10

11 Insert new Record public int InsertNewRecord(String name, int Age) throws SQLException Statement stmt = null; ResultSet rs = null; int rowcount = -1; Connection MySqlConn = null; try MySqlConn = getconnection(); stmt = MySqlConn.createStatement(); rowcount = stmt.executeupdate("insert student(name, age) values('" + name + "', " +Age + ")"); if (rowcount == 1) System.out.println("new row insert"); else System.out.println("Not insert"); catch (Exception ex) Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex); stmt.close(); return rowcount; Budditha Hettige 11

12 Show Records public void ReadAllRecords() try Statement stmt = null; ResultSet rs = null; Connection MySqlConn = null; int age; String name; MySqlConn = getconnection(); stmt = MySqlConn.createStatement(); rs = stmt.executequery("select * FROM student"); while (rs.next()) age = rs.getint("age"); name = rs.getstring("name"); System.out.println(name + ", " + age); rs.close(); stmt.close(); MySqlConn.close(); catch (Exception ex) Logger.getLogger(MySQLConnection.class.getName()).log(Level.SEVERE, null, ex); Budditha Hettige 12

13 Delete Records public void DeleteRows(String stuname) Statement stmt = null; ResultSet rs = null; Connection MySqlConn; int rowcount = -1; try MySqlConn = getconnection(); stmt = MySqlConn.createStatement(); int delete = stmt.executeupdate("delete FROM student WHERE name ='"+ stuname + "'"); if(delete == 1) System.out.println("Row is deleted."); else System.out.println("Row is not deleted."); stmt.close(); catch (Exception ex) Logger.getLogger(MySQLConnection.class.getName()).log(Level.SEVERE, null, ex); finally Budditha Hettige 13

14 Update Records public void updateage(string name, int newage ) try boolean result = false; Connection MySqlConn; Statement stmt = null; MySqlConn = getconnection(); String sql = "UPDATE student SET age =? WHERE name =?"; PreparedStatement prest = MySqlConn.prepareStatement(sql); prest.setint(1, newage); prest.setstring(2, name); int executeupdate = prest.executeupdate(); if (executeupdate > 0) System.out.println("Record Updaqted"); MySqlConn.close(); catch (Exception ex) Logger.getLogger(MySQLConnection.class.getName()).log(Level.SEVERE, null, ex); Budditha Hettige 14

15 Sample Program public static void main(string[] args) try Connection MySqlConn; MySQLConnection con = new MySQLConnection(); // con.getconnection(); MySqlConn = con.getconnection(); con.insertnewrecord("budditha", 34); con.insertnewrecord("saman", 25); con.insertnewrecord("kamal", 23); con.readallrecords(); con.deleterows("saman"); con.updateage("budditha", 35 ); con.readallrecords(); catch (Exception ex) Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex); Budditha Hettige 15