JDBC Vs. Java BlendPresentation by

Gopal Manchikanti

Shivakumar Balasubramanyam

JDBC Technology

INTRODUCTION

Structured Query Language(SQL)

Microsoft’s ODBC

Need for JDBC

About JDBC

SQL

Used to Create,Manipulate,Examine and Manage Databases

Application Specific Language

Unsuitable as a General Application Language

Another Language Needed for Visual Display and Report Generation

ODBCMicrosoft Product

C-Based Interface to SQL-Based Databases

Provides a consistent Interface for communicating

WHY JDBC?

ODBC not appropriate for direct use from Java

Translation of ODBC API into Java API - Not Desirable

ODBC is hard to Learn

JDBC is needed to enable a “pure Java” solution

JDBCCreates a Interface for communicating with Databases

Based on the X/Open SQL Call Level Interface

Allows Reuse of Database Connections - Connection Pooling

Useful in Accessing data across incompatible DBMS

JDBC

Easy to Learn and Use

Provides a truly portable solution to writing Database Applications

Talk to a variety of Databases

Maintain the Security, Robustness and Portability

JDBC Architecture

JDBC API for Application Writers

JDBC API for Driver Writers

JDBC - Two-Tier and Three-Tier Models

JDBC URL’s

The JDBC API

Establish a Connection with a Database java.sql.Environment - allows creation of new database connections

Send SQL statements java.sql.Statement - container class for embedded SQL statements

Process the results java.sql.ResultSet - access control to results of a statement

JDBC API

ClientDataBase Sever

Application GUI

JDBC API

Network Interface

Network Connection

SQL RequestsSQL Results SQL Results

JDBC Drivers

JDBC requires drivers to connect with individual Databases

Types of Drivers:

1.JDBC-ODBC bridge 2.Partial Java Driver 3.Pure Java driver for database middle ware 4.Direct-to-database pure Java driver

Two-tier and Three-tier Models

JDBC supports both two-tier and three-tier models for database access

Two-tier Model : Applet/Application talks directly to the database Requires a JDBC driver that can communicate with the database

Referred to as Client/Server Configuration

Client/Server Model

Client DataBase Sever

Application GUI

JDBC Driver

Network Interface

Network Connection

SQL RequestsSQL Results SQL Results

Network Interface

Two-tier and Three-tier Models

Three-tier Model :

Commands and Results sent to “middle tier” of services

Attractive as it maintains control on the accesses and updates

User can use a easy-to-use higher-level API

Middle-tier implemented in Java gives advantages of Robustness, Multithreading and Security features

Three-Tier Model

Client DataBase Sever

Application GUI

JDBC Driver(Cl)

Network InterfaceNetwork Interface

JDBC Driver(ser) Database Lib.

Network Interface Network Interface

Network ANetwork B

MIDDLE WARE

JDBC URL’s

Way of Identifying a database

Appropriate Driver recognizes it and establishes a connection

Allow driver writers to encode all necessary connection information

Allow a level of indirection

Standard syntax: jdbc:<subprotocol>:<subname>

Driver Manager

DriverManager class maintains a list of Driver classes

Driver classes need to register with the Driver Manager

Registration is done automatically by the driver when it loaded

Allows Keeping Track of Available Drivers

Connecting-Talking-Processing

A Connection Object represents a connection with a database

A Connection Session includes Statements executed and Results got

DriverManager.getConnection() - Standard way to establish connection

The method takes a string containing a URL

DriverManager tries to use each of the drivers in the order of registration

Connecting-Talking-Processing

DriverManager tests the drivers by calling the Driver.connect

The first driver that recognizes the URL makes the connection

Mechanism for reading and writing data between Java and SQL

JDBC define a set of generic SQL type identifiers

Dynamic Data Access

SECURITY Issues

Restriction from opening Network Connections

DataBase needs to reside on the WebServer

Key Features of JDBC

Full Access to Metadata

No Installation

Database Connection Identified by URL

Connection Pooling and Distributed Transactions

Advantages of JDBC

Leverage Existing Enterprise Data

Simplified Enterprise Development

Zero Configuration for Network Computers

For e-commerce applications running on the Internet

Gives all advantages of Java like Portability, Security and Robustness

FURTHER Advancements

JDBC is a base for Higher-Level APIs

Higher-Level APIs on top of JDBC :

An embedded SQL for Java - allows mixing SQL statements within Java Direct Mapping of Relational Database tables to Java classes.(Java Blend)