CSI 3125, Preliminaries, page 1 JDBC

CSI 3125, Preliminaries, page 2 JDBC JDBC stands for Java Database Connectivity, which is a standard Java API (application program interface ) for database-independent connectivity between the Java programming language and a wide range of databases. The JDBC library includes APIs for each of the tasks commonly associated with database usage: Making a connection to a database Creating SQL or MySQL statements Executing that SQL or MySQL queries in the database Viewing & Modifying the resulting records

CSI 3125, Preliminaries, page 3 JDBC Architecture:

CSI 3125, Preliminaries, page 4 JDBC Architecture: The JDBC API uses a driver manager and database-specific drivers to provide connectivity to different databases. The JDBC driver manager ensures that the correct driver is used to access each data source. JDBC drivers are normally provided by specific data base vendors and they act as the interface to communicate between JDBC and a database

CSI 3125, Preliminaries, page 5 JDBC Architecture: JDBC DriverManager DriverManager manage the different types of JDBC database driver. DriverManager's responsibility to load all the drivers found in the system properly. Driver Manager's duty to choose the most appropriate driver from the previously loaded drivers. JDBC DriverManager is a class in JDBC API and objects of this class can connect Java applications to a JDBC driver

CSI 3125, Preliminaries, page 6 JDBC Architecture: JDBC Driver JDBC Drivers are written by vendors and must support the basic features of the JDBC specification It serves as the interface to communications between JDBC and a database. It processes JDBC methods invocations, sends SQL statements to a specific data source, and returns results back to the application.

CSI 3125, Preliminaries, page 7 JDBC Architecture: Driver Type JDBC DRIVERS TYPES: JDBC driver implementations vary because of the wide variety of operating systems and hardware platforms in which Java operates. Sun has divided the implementation types into four categories: Type 1 - JDBC-ODBC Bridge Driver Type 2 - JDBC-Native Bridge Driver Type 3 - JDBC-Net Bridge Driver (Net pure Java) Type 4 - Direct JDBC Driver

CSI 3125, Preliminaries, page 8 JDBC Architecture: Driver Type Type 1 - JDBC-ODBC Bridge Driver In a Type 1 driver, a JDBC bridge is used to access ODBC drivers installed on each client machine. Since there are different types of databases and each of them has its own way of dealing with SQL queries and to return the results, ODBC provides identical results regardless of the type of database ODBC driver is included in the Java 2 SDK within the sun.jdbc.odbc package

CSI 3125, Preliminaries, page 9 JDBC Architecture: Driver Type Type 1 - JDBC-ODBC Bridge Driver In order to use Type 1 drivers ODBC must be installed on the computer having the driver Type 1 drivers are not suitable for developing web applications as they need software to be installed on client machine Using ODBC requires configuring on the system a Data Source Name (DSN) that represents the target database. ODBC is developed by Microsoft that enables communication between databases clients running on Windows and DBMS

CSI 3125, Preliminaries, page 10 JDBC Architecture: Driver Type Type 1 - JDBC-ODBC Bridge Driver

CSI 3125, Preliminaries, page 11 JDBC Architecture: Driver Type Type 2 - JDBC-Native Bridge Driver Type 2 drivers use the Java Native Interface (JNI) to make calls to a local database library API. This driver converts the JDBC calls into a database specific call for databases such as SQL, ORACLE etc i.e. This driver is specific to a particular database.

CSI 3125, Preliminaries, page 12 JDBC Architecture: Driver Type Type 2 - JDBC-Native Bridge Driver This driver communicates directly with the database server and requires some native code to connect to the database. These drivers typically provided by the database vendors and used in the same manner as the JDBC- ODBC Bridge, driver must be installed on each client machine. If we change the Database we have to change the native API driver as it is specific to a database. Cannot be used for the Internet.

CSI 3125, Preliminaries, page 13 JDBC Architecture: Driver Type Type 3 - JDBC-Net Bridge Driver (Net pure Java) The JDBC type 3 driver, also known as the network- protocol driver The middle-tier (application server) converts JDBC calls directly or indirectly into the vendor-specific database protocol. Type 3 database requests are passed through the network to the middle-tier server and the middle-tier server can in turn use Type1, Type 2 or Type 4 drivers to translate the request to the database. Since the communication between client and the middleware server is database independent, there is no need for the vendor db library on the client machine

CSI 3125, Preliminaries, page 14 JDBC Architecture: Driver Type Type 3 - JDBC-Net Bridge Driver (Net pure Java)

CSI 3125, Preliminaries, page 15 JDBC Architecture: Driver Type Type 4 – Direct JDBC Driver Type 4 drivers are pure Java drivers to communicate directly with the database. Like Type 3 drivers, they do not require native database libraries and can be deployed over the Internet without client installation. One drawback to Type 4 drivers is that they are database specific. Unlike Type 3 drivers, if your back-end database changes, you may have to purchase and deploy a new Type 4 driver. However, because Type 4 drivers communicate directly with the database engine rather than through middleware or a native library, they are usually the fastest

CSI 3125, Preliminaries, page 16 JDBC Architecture: Driver Type Type 4 – Direct JDBC Driver In a Type 4 driver, a pure Java-based driver that communicates directly with vendor's database through socket connection. This is the highest performance driver available for the database and is usually provided by the vendor itself. This kind of driver is extremely flexible, you don't need to install special software on the client or server. Driver completely written in Java

CSI 3125, Preliminaries, page 17 Driver Usage When accessing one type of database, such as Oracle, Sybase, or IBM, the preferred driver type is 4. when Java application is accessing multiple types of databases at the same time, type 3 is the preferred driver. Type 2 drivers are useful in situations where a type 3 or type 4 driver is not available yet for your database. The type 1 driver is used for development and testing purposes only.

CSI 3125, Preliminaries, page 18 JDBC The java.sql package contains the entire set of interfaces and classes defined by JDBC API that sends SQL (Structured Query Language) statements to relational databases and retrieves the results of executing those SQL statements.

CSI 3125, Preliminaries, page 19 JDBC Program Steps Step 1: Create a table check(id:PK, u_name:Text, age:number) in the any database such as(MS Access, Oracle, MySQL,SQL..) Create Data Source Name, using ODBC Step 2: Import JDBC Packages (import java.sql.*;) Step 3: Register JDBC Driver: Load database specific driver by calling Class.forName("Name of the driver class file"). Syntax - Class.forName("sun.jdbc.odbc.jdbcOdbcDriver"); The Class class is avaliable in java.lang package. The database driver is different for each DBMS. The type1 driver is same for all the databases.

CSI 3125, Preliminaries, page 20 JDBC Program Steps Step 4: Once JDBC driver is loaded, The DriverManager is used to establish connection with database server using getConnection() method. The Connection type is the return type of getConnection(). The DriverManager and Connection are available in java.sql package. Syntax - Connection con=DriverManager.getConnection("URL","userid","password "); URL - jdbc:odbc: Userid : user Id of database (Optional) Password : Password of database (Optional)

CSI 3125, Preliminaries, page 21 JDBC Program Steps Step 5: Creating a jdbc Statement object Statement statement = dbConnection.createStatement(); eg: Statement stmt = con.createStatement() ; String query = "SELECT col1, col2, col3 FROM sometable”; Step 6: ResultSet resultSet = statement.executeQuery(query);

CSI 3125, Preliminaries, page 22 JDBC Prog Database: db.mdb, DSN: ds, table check(id:Pk,u_name:text,age:number) import java.sql.*; public class db6 {public static void main(String[] args) {try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection con = DriverManager.getConnection("jdbc:odbc:ds"); Statement stmt = con.createStatement(); ResultSet rs = stmt.executeQuery("select * from check"); while (rs.next()) System.out.println("Name " + rs.getString("u_name") + " Age " +rs.getString("age")); con.close(); } catch (SQLException e) {System.out.println(e);} catch (Exception e) {System.out.println(e);} }

CSI 3125, Preliminaries, page 23 JDBC Prog Database: db.mdb, DSN: ds, table check(id:Pk,u_name:text,age:number) Insert a row in the table Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection con = DriverManager.getConnection("jdbc:odbc:ds"); Statement stmt = con.createStatement(); stmt.executeUpdate("insert into check (u_name,age) values('appu',23)");

CSI 3125, Preliminaries, page 24 JDBC Prog insert & display Database: db.mdb, DSN: ds, table check(id:Pk,u_name:text,age:number) import java.sql.*; public class db7 {public static void main(String[] args) throws Exception { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection con = DriverManager.getConnection("jdbc:odbc:ds"); Statement stmt = con.createStatement(); stmt.executeUpdate("insert into check (u_name,age) values('appu',23)"); ResultSet rs=stmt.executeQuery("select *from check"); while (rs.next()) System.out.println("Name " + rs.getString("u_name") + " Age " +rs.getString("age")); con.close(); }

CSI 3125, Preliminaries, page 25 JDBC Prog update Database: db.mdb, DSN: ds, table check(id:Pk,u_name:text,age:number) Connection con = DriverManager.getConnection("jdbc:odbc:ds"); Statement stmt = con.createStatement(); stmt.executeUpdate("update check set u_name='zoo' where u_name='appu'");

CSI 3125, Preliminaries, page 26 JDBC Prog delete Database: db.mdb, DSN: ds, table check(id:Pk,u_name:text,age:number) Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection con = DriverManager.getConnection("jdbc:odbc:ds"); Statement stmt = con.createStatement(); stmt.executeUpdate("delete from check where u_name='zoo'");

CSI 3125, Preliminaries, page 27 JDBC Prog delete Database: db.mdb, DSN: ds, table check(id:Pk,u_name:text,age:number)

CSI 3125, Preliminaries, page 28 JDBC Prog delete Database: db.mdb, DSN: ds, table check(id:Pk,u_name:text,age:number)

CSI 3125, Preliminaries, page 29 JDBC Prog import java.sql.*; public class database {public static void main(String[] args) { Connection conn=null; try{ Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); } catch(ClassNotFoundException e){ System.out.println(e);} try{ conn = DriverManager.getConnection("jdbc:odbc:ds"); } catch(SQLException se) { System.out.println(se);} System.out.println("connection is successful!!!"); try{ String selectSQL = "select * from check"; Statement stmt = conn.createStatement(); ResultSet rset = stmt.executeQuery(selectSQL); while(rset.next()){ System.out.println("ID: " + rset.getString(1) + " NAME: " +rset.getString(2) + " Age: "+rset.getString(3) ); } stmt.close(); } catch(SQLException se) { System.out.println(se);} }