1. Introduction to Programming with Java1

2. Chapter 3 Database Programming2

3. JDBC Introduction
Java Data Base Connectivity(JDBC) is a set of Java APIs used for executing SQL statements.
JDBC is much similar to Microsoft’s Open Database Connectivity(ODBC) interface to SQL (Structure Query Language).
JDBC API is a set of interfaces and classes to be used for communicating with a database. These interfaces and classes are found in the java.sql package.
JDBC allows developers to write client/server properties in Java.
JDBC is an interface that stands between the specific database and the Java applications, applets and Servlets.
Why JDBC is advantageous with Java? The reason behind that is programs developed with the java programming language and JDBC are platform independent.

4. Role of JDBC Establishes connection with the database.
Sends SQL statements.
Process the results
Close the connection.

5. JDBC Characteristics It is call-level SQL interface for Java.
It does not restrict the type of queries of passed to an underlying DBMS driver.
JDBC mechanisms are simple to understand and use.
It provides Java Interface that stays consistent with the rest of the Java system.

6. The Design of the JDBC
At the initial, when the Sun team wants to built the database they extends the standard Java Library to deal with the SQL access to database. Because of this it is impossible task it didn’t take them very long to realize.
Afterwards with the help of networking protocols Sun works on the pure java API for the SQL access.
Then much of time later the API for the database access become the JDBC API, and the rules for writing drivers were encapsulated in the JDBC driver API.

7. The Design of the JDBC Simple Design
JDBC consists of two layers: the top layer is the JDBC API and the bottom layer is the JDBC driver API
Java Application
JDBC Driver Manager
JDBC/ODBC
Bridge
ODBC
driver
Vender supplied JDBC driver
Data Base
Server

8. The Design of the JDBC Simple Design
The top layered API communicates with the JDBC manager driver API sending it the various SQL statements.
Afterwards the manager communicates with the various third party drivers that actually connect to the database and return the information from the query or perform the action specified by the query.
The Driver Manager also helps to select the most appropriate driver from the previously loaded drivers when a new open database is connected.

9. The Design of the JDBC Two – tier and Three – tier Models
Two – tier Model
Java applications/applets interact directly with the database.
This model is referred to as client/server model where user is the client and the machine that has the database is called the server.
First the is the JDBC API layer and second is the various third party drivers.
Java Application
JDBC
DBMS
Client Machine (GUI)
DBMS proprietary protocol
Database Server

10. The Design of the JDBC Two – tier and Three – tier Models
A middle tier is introduced in this model.
Uses of the middle tier:
It collects the SQL statement from the client and hands it over to the database.
Receives results from the database to the client.
Controls accessing and updating of data.
This three tier architecture introduces the Java API calls the middleware layer that in turn accesses the data.
Java Applet or HTML browser
Client Machine (GUI)
HTTP, RMI or COBRA calls
Remote Method Invocation
Application Server(Java)
Server machine (Business Logic)
JDBC
DBMS proprietary protocol
DBMS
Database Server eg. SQL Server
Oracle

11. The Design of the JDBC Two – tier and Three – tier Models

12. JDBC Drivers
The 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.
This translation layer provides JDBC application with database independence. If the back-end database changes, only the JDBC driver need to be replaced with few code modifications required.

13. Type 1: JDBC ODBC Bridge Driver
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14. Type 1: JDBC ODBC Bridge Driver
Type 1 drivers act as a “bridge” between JDBC and another database connectivity mechanism such as ODBC.
Sun provided a JDBC-ODBC Bridge driver: sun.jdbc.odbc.JdbcOdbcDriver.
In this driver the java statements are converted to jdbc statement.
JDBC statements call the ODBC by using the JDBC-ODBC Bridge. And finally the query is executed by the database.
This bridge is helpful for testing but it cannot recommend for the production used.
Type 1 only runs on platforms where ODBC is available.
This driver is native code and not Java i.e it is written in C or C++ language not in Java

15. Type 2: Native-API Driver

16. Type 2: Native-API Driver
Type 2 driver converts JDBC API calls to the native C or C++ API calls.
This driver converts the JDBC calls into a database specific call for databases such as SQL, ORACLE etc.
This driver communicates directly with the database server. It require some native code to connect to the database.
Type 2 drivers are usually faster than type 1 drivers.

17. Type 3: Network Protocol Driver

18. Type 3: Network Protocol Driver Or All-Java Driver
Type 3 drivers are pure Java drivers that use a proprietary network protocol to communicate with JDBC middleware on the server.
The middleware then translates the network protocol to database-specific function call.
Type 3 drivers can be deployed over the Internet without client installation. Java----> JDBC statements-----> SQL statements >databases.

19. Type 4: Database Protocol Driver

20. Type 4: Database Protocol Driver
The JDBC type 4 driver, also known as the Direct to Database Pure Java Driver, is a database driver implementation that converts JDBC calls directly into a vendor- specific database protocol.
Written completely in Java, type 4 drivers are thus platform independent.
They install inside the Java Virtual Machine of the client.

21. JDBC API Interfaces in java.sql package Interfaces Methods Array
getArray(), getBaseType, getResultSet
Blob
getBinaryStream, getBytes, length, position
CallableStatement
registerOutParameter, wasNull
Clob
getAsciiStream, getCharacterStrea, getSubString, length, position
Connection
commit, createStatement, isClosed, isReadOnly, rollback
DatabaseMetadata
getColumns, getConnection,
ResultSet
absolute, afterLast, beforeFirst, close, next, previous, deleteRow, insertRow
Statement
cancel, close, executeUpdate, getConnection, getMaxRows
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22. JDBC API Classes in java.sql package Classes Methods Date
getHours, getMinutes, setTime, toString, valueOf
DriverManager
getConnection, println, registerDriver, getDriver
Time
getDate, getYear, getMonth, setTime, setYear
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23. Essential JDBC progam Import the java.sql package import java.sql.*;
Steps for using JDBC to access Database
Import the java.sql package
import java.sql.*;
Load a JDBC driver
All drivers are required to register themselves at load time.
try {
Class.forName("com.mysql.jdbc.Driver"); }
catch(Exception e)
System.out.println("Unable to load the driver...");
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24. Essential JDBC progam Connect to the database
Steps for using JDBC to access Database
Connect to the database
The JDBC DriverManager Class defines objects which can connect
java applications to a JDBC driver, which is backbone of JDBC
architecture.
getConnection() method used to establish connection.
Connection con = DriverManager.getConnection("jdbc:mysql://localhost/db_hms","root","");
Create a statement
To execute SQL statements, we need to initiate a statement object
form our connection object by using createstatement() method.
con.createstatement();
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25. Essential JDBC progam
Steps for using JDBC to access Database
There are 3 types of statement
Statement: Simple SQL queries without parameters.
Prepared Statement: Executed precompiled SQL queries with or without parameters. PrepareStatement objects are precompile SQL statement.
Callable Statement: Execute a call to a database stored procedure.
CallableStatement objects are SQL stored procedure call statements
Execute the statement
stmt.exeuteUpdate(String str);
To exeute query executeQuery() methods comes in picture. The
executeQuery() method takes SQL query as a parameter and returns
the result of the query as the ResultSet Object.

26. Essential JDBC progam Retrieve the result
Steps for using JDBC to access Database
Result rs1=stmt.executeQuery("Select id, name,salary from teacher
where department="Computer" ");
Retrieve the result
while(rs1.next()) {
int x=rs1.getInt(1);
String s=rs1.getString("b"); }
The above is just an example where rs1 is a ResutlSet object. The results
of the SQL statements are stored in a ResultSet object. To retrieve the data from this object, we use the getXXX methods. To move to the next row, we make use of rs1.next() method.

27. Essential JDBC progam Close the statement and the connection:
Steps for using JDBC to access Database
Close the statement and the connection:
stmt.close();
con.close();
con.commit();
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28. Essential JDBC progam
Steps for using JDBC to access Database
Write JDBC program to accept employee information from database and update first tuple and display after updating.
Write JDBC program that insert the following details to a teacher table having the following structure.
teacher_name, department, salary