Java presentation

PREPARED BY:• NITESH KUKREJA• POOJA TALREJA

What is JDBC?

• JDBC is Java application programming interface that allows the Java programmers to access database management system from the java code.

• It was developed by JavaSoft, a subsidiary of Sun Microsystems.

• It is a java API which enables the java programs to execute SQL statements.

Job of JDBC

• JDBC provides methods for querying and updating the data in Relational Database Management system such as SQL, Oracle etc.

• Generally all Relational Database Management System supports SQL and we all know that Java is platform independent.

• So JDBC makes it possible to write a single database application that can run on different platforms and interact with different Database Management Systems.

Components of JDBC

• 1. The JDBC API.

• 2. The JDBC Driver Manager.

• 3. The JDBC Test Suite.

• 4. The JDBC-ODBC Bridge.

JDBC API

• The JDBC API provides the facility for accessing the relational database from the Java programming language.

• The user not only execute the SQL statements, retrieve results, and update the data but can also access it anywhere within a network because of it's "Write Once, Run Anywhere" (WORA) capabilities.

• Due to JDBC API technology, user can also access other tabular data sources like spreadsheets or flat files even in the a heterogeneous environment.

JDBC API(Cont.)

• JDBC application programming interface is a part of the Java platform that have included Java SE and Java EE in itself.

• The latest version of JDBC 4.0 application programming interface is divided into two packages.i) java.sql.ii) javax.sql.

• Java SE and Java EE platforms are included in both the packages.

JDBC Driver Manager

• The JDBC Driver Manager is a very important class that defines objects which connect Java applications to a JDBC driver.

• Usually Driver Manager is the backbone of the JDBC architecture.

• It's very simple and small that is used to provide a means of managing the different types of JDBC database driver running on an application.

JDBC Driver Manager(Cont.)

• The main responsibility of JDBC database driver is to load all the drivers found in the system properly as well as to select the most appropriate driver from opening a connection to a database.

• The Driver Manager also helps to select the most appropriate driver from the previously loaded drivers when a new open database is connected.

JDBC Test Suite

• The function of JDBC driver test suite is to make ensure that the JDBC drivers will run user's program or not .

• The test suite of JDBC application program interface is very useful for testing a driver based on JDBC technology during testing period.

• It ensures the requirement of Java Platform Enterprise Edition (J2EE).

ODBC(Open Data Base Connectivity)

• Open DataBase Connectivity is similar to Java Database Connectivity which is used for accessing and managing database, but the difference is that JDBC is designed specifically for Java programs, whereas ODBC is not depended upon any language.

JDBC-ODBC Bridge

• The JDBC-ODBC bridge, also known as JDBC type 1 driver is a database driver that utilize the ODBC driver to connect the database.

• This driver translates JDBC method calls into ODBC function calls.

• The Bridge implements Jdbc for any database for which an Odbc driver is available.

• The Bridge is always implemented as the sun.jdbc.odbc Java package and it contains a native library used to access ODBC.

Now we can conclude this topic:

• This first two component of JDBC, the JDBC API and the JDBC Driver Manager manages to connect to the database and then build a java program that utilizes SQL commands to communicate with any RDBMS.

• On the other hand, the last two components are used to communicate with ODBC or to test web application in the specialized environment.

Architecture of JDBC

JDBC Driver

• A JDBC driver translates standard JDBC calls into a network or database protocol OR into a database library API call that facilitates communication with the database.

• There are four distinct types of JDBC drivers.

1. JDBC-ODBC Bridge + ODBC Driver, also called as Type1

2. Native API , Pure/partly Java Driver, also called Type 2.

3. JDBC –Net Pure Java Driver, also called Type 3.

4. Native Protocol , Pure Java Driver, also called Type 4.

JDBC-ODBC Bridge

Functions of JDBC-ODBC Bridge

• Translates query obtained by JDBC into corresponding ODBC query, which is then handled by the ODBC driver.

• Sun provides a JDBC-ODBC Bridge driver. sun.jdbc.odbc.JdbcOdbcDriver. This driver is native code and not Java, and is closed source.

• Client -> JDBC Driver -> ODBC Driver -> Database

• There is some overhead associated with the translation work to go from JDBC to ODBC.

Native-API Driver

Functions of Native-API Driver

• This type of driver converts JDBC calls into calls to the client API

• Better performance than Type 1 since no jdbcto odbc translation is needed.

• Client -> JDBC Driver -> Vendor Client DB Library -> Database for that database.

Network-Protocol Driver

Functions of Network Protocol Driver

• Follows a three tier communication approach.

• Can interface to multiple databases - Not vendor specific.

• The client driver to middleware communication is database independent.

• Client -> JDBC Driver -> Middleware-Net Server -> Any Database

Native-Protocol Driver

Functions of Native Protocol Driver

• It is entirely written in Java that communicate directly with a vendor's database through socket connections. No translation or middleware layers, are required, improving performance.

• The driver converts JDBC calls into the vendor-specific database protocol so that client applications can communicate directly with the database server.

• Completely implemented in Java to achieve platform independence.

• Client Machine -> Native protocol JDBC Driver -> Database server

SQL Package

• Provides the API for accessing and processing data stored in a data source (usually a relational database) using the Java programming language.

• This API includes a framework whereby different drivers can be installed dynamically to access different data sources.

• Although the JDBCTM API is mainly geared to passing SQL statements to a database, it provides for reading and writing data from any data source with a tabular format.

• The reader/writer facility, available through the javax.sql.RowSet group of interfaces, can be customized to use and update data from a spread sheet, or any other tabular data source.

CONTENTS OF SQL PACKAGE

• The java.sql package contains API for the following:

1. Making a connection with a database via the DriverManager facility

Class or Interface Purpose

DriverManager class makes a connection with a driver

SQLPermission class provides permission when code running within a Security Manager, such as an applet, attempts to set up a logging stream through the DriverManager

Driver interface provides the API for registering and connecting drivers based on JDBC technology ("JDBC drivers"); generally used only by the DriverManager class

DriverPropertyInfo class provides properties for a JDBC driver; not used by the general user

Cont..

2. Sending SQL statements to a database

3. Retrieving and updating the results of a query

• ResultSet interface

Class or Interface Purpose

Statement class used to send basic SQL statements

PreparedStatement class used to send prepared statements or basic SQL statements (derived from Statement)

CallableStatement class used to call database stored procedures (derived from PreparedStatement)

Connection interface provides methods for creating statements and managing connections and their properties

Savepoint provides savepoints in a transaction

Cont..4. Standard mappings for SQL types to classes and interfaces in the Java programming language

Class or Interface Purpose

Array interface mapping for SQL ARRAY

Blob interface mapping for SQL BLOB

Clob interface mapping for SQL CLOB

NClob interface mapping for SQL NCLOB

Date class mapping for SQL DATE

Ref interface mapping for SQL REF

RowId interface mapping for SQL ROWID

Struct interface mapping for SQL STRUCT

SQLXML interface mapping for SQL XML

Time class mapping for SQL TIME

Timestamp class mapping for SQL TIMESTAMP

Types class provides constants for SQL types

Cont..5. Custom mapping an SQL user-defined type (UDT) to a class in the Java programming language

Class or Interface Purpose

SQLData interface specifies the mapping of a UDT to an instance of this class

SQLInput interface provides methods for reading UDT attributes from a stream

SQLOutput interface provides methods for writing UDT attributes back to a stream

6. Metadata

Class or Interface Purpose

DatabaseMetaData interface provides information about the database

ResultSetMetaData interface provides information about the columns of a ResultSet object

ParameterMetaData interface provides information about the parameters toPreparedStatement commands

Cont..7. Exceptions

Exception Reason

SQLException thrown by most methods when there is a problem accessing data and by some methods for other reasons

SQLWarning thrown to indicate a warning

DataTruncation thrown to indicate that data may have been truncated

BatchUpdateException thrown to indicate that not all commands in a batch update executed successfully

JDBC DATA TYPES

JDBC TYPE JAVA TYPE

BIT boolean

TINY INT byte

SMALL INT short

INTEGER int

BIG INT long

REAL Float

FLOATDOUBLE

Double

BINARYVARBINARYLONGVARBINARY

byte[]

CHARVARCHARLONGVARCHAR

String

JDBC TYPE JAVA TYPE

NUMERICDECIMAL

BigDecimal

DATE java.sql.Date

TIMETIMESTAMP

java.sql.Timestamp

CLOB Clob

BLOB Blob

ARRAY Array

DISTINCT Mapping of underlying type

STRUCT Struct

REF Ref

JAVA_OBJECT Underlying java class

SEVEN BASIC STEPS IN ESTABLISHING CONNECTION WITH DATABASE

1. Load the driver.

2. Define the Connection URL.

3. Establish the Connection.

4. Create a Statement object.

5. Execute a Query.

6. Process the results.

7. Close the connection.

STEP 1-LOAD THE DRIVER

Not required in Java 6• In Java SE 6.0 and later(Java 4.0 and later), the driver is loaded

automatically.

In Java 7,For this step, DriverManager class is required.• The DriverManager class maintains the list of the Driver classes.

Each driver has to be get• registered in the DriverManager class by calling the method

DriverManager.registerDriver().• By calling the Class.forName() method the driver class get

automatically loaded.

Syntax of Class.forName() method:Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”);

DriverManager Class

Following are the methods of DriverManager class:

1. deregisterDriver(Driver driver) : It drops the driver from the list of drivers registered in the DriverManager class.

2. registerDriver(Driver driver) : It registers the driver with the DriverManager class.

3. getConnection(String url) : It tries to establish the connection to a given database URL.

4. getConnection(String url, String user, String password) : It tries to establish the connection to a given database URL.

5. getConnection(String url, Properties info) : It tries to establish the connection to a given database URL.

6. getDriver(String url) : It attempts to locate the driver by the given string.

7. getDrivers() : It retrieves the enumeration of the drivers which has been registered with the DriverManager class.

STEP 2-DEFINE THE CONNECTION URL

• This URL has three parts:

“jdbc:odbc:MyDataSource”

<Protocol><subprotocol>MyDataSource<subname>

<protocol> in a JDBC URL is always jdbc

<subprotocol> is the name of the database connectivity mechanism. If the mechanism to retrieve the data is an ODBC -JDBC bridge. The sub protocol is odbc

<subname> is used to identify the database.

Data Source

Data Source is the source to which the connection is to be established. It can be in MySQL, MS Access, etc. Before establishing the connection, we need to configure the data source so that we can use it in our java application. Following are the steps for creating a data source:

Step 1- GoTo Control Panel -> System and Security->Administrative tools.Click on Data Sources(ODBC)

Step 2- A window will appear like this, User DSN tab appears by default. Click on System DSN tab.

Step 3- In System DSN, click on Add button

Step 4- In this window, select the type of driver as per the database. For MS Access select the Driver do Microsoft Access(*.mdb)

Step 5- Now, in this give a name to your DSN and specify the path of your mdb file by clicking on Select button and click on OK.

Step 6- Now, your data source will be added in the list.

Step 3 – ESTABLISH THE CONNECTIONA Connection object represents a connection with a database.When we connect to a database by using connection method, we create a Connection Object, which represents the connection to the database. An application may have one or more than one connections with a single database or many connections with the different databases also.

In the first step we have loaded the database driver to be used. Now its time to make the connection with the database server. Following code we have used to make the connection with the database:

Syntax :Connection conobj = DriverManager.getConnection(String url);Where, conobj – is the object of connection Class that represent a connection between the database and the clienturl – is the connection url.

Step 4- Create a Statement object

Idea:• Once a connection is obtained we can interact with the database. The JDBC Statement, CallableStatement, and PreparedStatement interfaces define the methods and properties that enable you to send SQL or PL/SQL commands and receive data from your database.

• They also define methods that help bridge data type differences between Java and SQL data types used in a database.

Types of Statements:• Statement – eg. Select statement

• PreparedStatement – eg. Insert, Update, Delete, etc• CallableStatement - eg. Stored procedures and functions

Example:Statement s=con.createStatement();

Step 5 – Execute a Query• The executeQuery() method of Statement interface is used to execute queries to the database.• This method returns the object of ResultSet that can be used to get all the records of a table.• Syntax:

public ResultSet executeQuery(String sql)throws SQLException• Example:

ResultSet rs=stm.executeQuery(“Select * from student”);

• The executeUpdate() method of Statement interface is used to execute queries to the database.• It is used to insert, delete, and update the database• Syntax:

int executeUpdate(String sql)throws SQLException• Example:

int i=stm.executeUpdate(“insert into student values(11,’name’)”);

Step 6 – Process the Result

In this step we receives the result of execute statement. In this case we will fetch the employees records from the recordset object and show on the command prompt. Here is the code:// 0 1 //name rollno

while (res.next()){String studName = res.getString( “student_name " );//String studName = res.getString( 0); // index of columnSystem.out.println( studName );int roll = res.getInt(1);int roll = res.getInt(“roll_no”);System.out.println( +roll );}

Step 7 – Close the connection

• By closing connection object Statement and ResultSet will be closed automatically. The close() method of Connection interface is used to close the connection.

• Syntax:public void close()throws SQLException

• Example:con.close();