JDBC

Java API for Database Connectivity

Layout of this recitation

• Introduction to JDBC API

• JDBC Architecture

• Understanding the design of JDBC API– Classes and relations among them

What is an API?

• application program interface

• a set of routines, protocols, and tools for building software applications

• provides all the building blocks

What you expect in DB API

1. Open a Connection

2. Send a statement

3. Retrieve results

4. Close a connection 1. Create a connection Session

2. Execute statement

3. Send results

4. Close the session

Java Application

DBMS Engine

Java DB API

Big picture

Java Application

JDBC Manager

JDBC Drivers

JDBC API

JDBC Driver API

Data Sources

Grey Area

JDBC driver type-1

• Uses the existing API

• Not the fastest

JDBC-ODBC Bridge

ODBC Driver

Native Driver

Net Driver

Java

Non Java

JDBC driver type-2

• Uses vendor-provided local libraries

• Most efficient

JDBC Driver

Native Driver

Net Driver

Java

Non Java

JDBC driver type-3 & 4

• 100% java.

JDBC – Net Driver Java

JDBC Driver Implements a proprietary

Protocol in javaJava

Complete JDBC Architecture

Java Application

JDBC Driver Manager

JDBC Net

Driver A

JDBC–ODBC Bridge B

JDBC Driver C

JDBC Driver D

ODBC Driver

Native Driver B

Native Driver C

JDBC Interface

JDBC Driver Interface

A B DC

On Different Platforms

DBMS

PC

MAC

Unix

JDBC Driver

Classes

JDBC API

JDBC Interface classes

• Java.sql package– DriverManager– Connection– Statement– CallableStatement– PreparedStatement– Resultset– ResultSetMetaData– DatabaseMetatData

JDBC Interfaces

Driver Manager

Connection Connection Connection

StatementPrepared Statement

ResultSet

Simple ExampleImport java.sql;class SimpleExample {

public static void main(String args[]) {String url = “jdbc:odbc:mysource”;try {

Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);Connection myConnection = DriverManager.getConnection(url,”Bond”,”TopSecret”);myConnection.close();

}catch(java.lang.Exception) {

ex.printStackTrace();}

}}

Sending SQL statements

……

String query= “Select name,id,salary FROM employees ORDER By salary”;

Connection myConnection = DriverManager.getConnection(…..);

Statement myStatement = myConnection.createStatement();

ResultSet rs = myStatement.executeQuery(query);

While(rs.next){

String empName = rs.getString(1);

String empId = rs.getString(2);

String empSalary = rs.getString(3);

System.out.println(“Employee ” + empName + “ with id ” + empId

+ “ earns ” + empSalary);

}

myStatement.close();

myConnection.close();

…….

Statement’s Execute Methods

• ResultSet executeQuery()– For SQL selects

• int executeUpdate()– For Update,Delete,Insert and Create etc.

• boolean execute()– For either type– Returns resultSetisAvailable

Statements

• Statement

• PreparedStatement

• CallableStatement

Additional stuff

• Datatypes: basic to CLOB, BLOB

• Transaction Management

• DDA with/without cursors

• Batch updates

• Metadata – DatabaseMetaData– ResultSetMetaData– ParameterMetaData

Advanced Techniques

• Connection Pooling

• Dynamic SQL with Prepared Statements

• Auto-generated keys

References

• www.google.com

• http://java.sun.com/j2se/1.4/docs/api/

• JDBC 3.0: Java Database Connectivity.– Bernard Van Haecke