Helena Pomezná, ciz034

St. skupina: L392

FEI, VŠB-TUO

Ak. rok. 2002/2003

Download: http://homel.vsb.cz/~ciz034/cze/study.html

Some facts about JDBC

How to make our application

What is the JDBC API?

JDBC = Java Database Connectivity

a Java API for accessing virtually any kind of tabular data

Consists of a set of classes and interfaces that provide a standard API for tool/database developers

Makes it easy to send SQL statements to relational database systems

Supports all dialects of SQL.

The value of JDBC

Can access virtually any data source Can run on any platform with a JVM We don’t have to worry about writing different applications to run on different platforms

=> lets a programmer write once and run anywhere.

What does the JDBC API do?

A JDBC technology-based driver = JDBC driver makes it possible to do 3 things:

Establish a connection with a data source

Send queries and update statements to the data source

Process the results.

The JDBC versus ODBC

ODBC API (Open DataBase Connectivity) was the most widely used programming interface for accessing databases.

Why not use ODBC from Java?

You can use ODBC from Java, but this is best done with the help of the JDBC API in the form of the JDBC-ODBC Bridge.

ODBC is not appropriate for direct use from the Java because it uses a C interface.

A literal translation of the ODBC C API into a Java API would not be desirable.

ODBC is hard to learn.

Java Software Framework

Java Software provides 3 JDBC product components:

the JDBC driver manager (included in Java2 Platform)

the JDBC driver test suite(on JDBC web site)

the JDBC-ODBC bridge (included in the Solaris and Windows versions of the Java2 Platform)

How to do it?

Installation

Setting Up a Database

Establishing a Connection

Creating Complete JDBC Applications

Installation

Install Java and JDBC on your machineYou will get JDBC when you download the JDK

Install driver on your machineJDBC driver

JDBC-ODBC Bridge driver

ODBC driver

Setting Up a Database

We will assume that the database already exists.

When you create the tables as examples below, they will be in the default database.

Establishing a ConnectionLoading Drivers

We want to use the JDBC-ODBC Bridge Class.forName(

“sun.jdbc.odbc.JdbcOdbcDriver”);

For instance, if the class name is jdbc.DriverXYZ

Class.forName(“jdbc.DriverXYZ”);

Establishing a Connection 2

Making the connection

Connection con = DriverManager.getConnection (url,

“myLogin”, “myPassword”);

Creating complete JDBC applications

Putting code in class definition

Importing classes to make them visible

import java.sql.*;

Using try and catch blocksSQLException

ClassNotFoundException

Using SQL

Using SQL

Creating a TableString createTableContact = “CREATE TABLE CONTACT“ +

“(FIRST VARCHAR(32), LAST VARCHAR(32), EMAIL VARCHAR(32))”;

Creating JDBC StatementStatement stmt = con.createStatement();

stmt.executeUpdate(createTableContact);

Using SQL - continuation

Entering data into a table

first line:stmt.executeUpdate(“INSERT INTO CONTACT “ + “VALUES

(‘Thomas’, ‘Willson’, ‘t.wil@vili.com’)”);

second line:stmt.executeUpdate(“INSERT INTO CONTACT “ + “VALUES

(‘Jane’, ‘Willson’, ‘j.wil@vili.com’)”);

Simple example

import java.sql.*;

Public class Lookup{public static void main(String[] args) throws SQLException, ClassNotFoundException{

String dbUrl = “jdbc:odbc:contact”;String user = “”;String pass = “”;

Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);Connection con =

DriverManager.getConnection( dbUrl, user, pass);

Statement sta = con.createStatement();

Simple example - continuation

ResultSet res = sta.executeQuery( “SELECT FIRST, LAST, EMAIL “ + “FROM contact.csv contact” + “WHERE” + “(LAST = ‘ “ + args[0] + “,) “ + “ORDER BY FIRST”);

while(res.next()){

System.out.println(res.getString(“Last”) + “, “ + res.getString(fiRST”) + “: “ + res.getString(“EMAIL”));

}

sta.close();

}

Sources

• http://java.sun.com/docs/books/tutorial

- the Java Tutorial

• Thinking in Java 2nd Edition, Bruce Eckel

Thank you