JDBC makes it very easy to connect to DBMS and to manipulate the data in it.

1. JDBC
Java Database Connectivity
Rohit Jain
DTU
B.Tech, Software Engineering

2. What is JDBC?
 JDBC API allows Java programs to
connect to DBs
 Provides cross-vendor connectivity and
data access across relational databases
from different vendors
 Classes and interfaces allow users to
access the database in a standard way
 The JVM uses the JDBC driver to
translate generalized JDBC calls into
vendor specific database calls

3. What Does JDBC Do ?
JDBC makes it possible to do three things:
Establish a connection with a database
Send SQL statements
Process the results.

4. JDBC Classes for DB
Connection
 java.sql.Driver
◦ Unless creating custom JDBC implementation, never
have to deal with it. It gives JDBC a launching point
for DB connectivity by responding to
DriverManager connection requests
 java.sql.DriverManager
◦ Maintains a list of Driver implementations and
presents an application with one that matches a
requested URL.
◦ getConnection(url, uid, password)
◦ getDrivers(), registerDriver()
 java.sql.Connection
◦ Represents a single logical DB connection; used for
sending SQL statements

5. JDBC Drivers
 JDBC-ODBC bridge
 Part Java, Part Native Driver
 Intermediate DAccess Server
 Pure Java Drivers

6. Driver Manager
 The purpose of the
java.sql.DriverManger class in JDBC is
to provide a common access layer on top
of different database drivers used in an
application
 DriverManager requires that each driver
required by the application must be
registered before use
 Load the database driver using
ClassLoader
 Class.forName(“oracle.jdbc.driver.Oracle
Driver”);

7. Registering a JDBC Driver
 Driver must be registered before it is
used.
 Drivers can be registered in three
ways.

8. Most Common Approach is
 To use Java’s Class.forName()
 Dynamically loads the driver’s class
file into memory
 Preferable because
It allows driver registration
configurable and portable.

9.  The second approach you can use to
register a driver is to use the static
DriverManager.registerDriver( )
method.
 Use the registerDriver( ) method if
you
are using a non-JDK compliant JVM.
For example:
DriverManager.registerDriver(new
oracle.jdbc.driver.OracleDriver( ));

10.  The third approach is to use a
combination of Class.forName( ) to
dynamically load the Oracle driver and
then the driver classes' getInstance( )
method to work around noncompliant
JVMs.
 For example:
Class.forName("oracle.jdbc.driver.Oracle
Driver").newInstance();

11. Basic steps to use
a database in Java
 Establish a connection
 Create JDBC Statements
 Execute SQL Statements
 GET ResultSet
 Close connections

12. 1. Establish a connection
 import java.sql.*;
 Load the vendor specific driver
◦ Class.forName("oracle.jdbc.driver.OracleDriver");
 What do you think this statement does, and how?
 Dynamically loads a driver class, for Oracle database
 Make the connection
◦ Connection con = DriverManager.getConnection(
"jdbc:oracle:thin:@oracle-prod:1521:OPROD", username,
passwd);
 What do you think this statement does?
 Establishes connection to database by obtaining
a Connection object

13. 2. Create JDBC statement(s)
 Statement stmt = con.createStatement()
;
 Creates a Statement object for
sending SQL statements to the
database

14. 3.Executing SQL Statements
 String createStudent = "Create table
Student " +
"(SSN Integer not null, Name
VARCHAR(32), " + "Marks Integer)";
stmt.executeUpdate(createStudent);
//What does this statement do?
 String insertStudent = "Insert into
Student values“ +
"(123456789,abc,100)";
stmt.executeUpdate(insertStudent);

15. Execute Statements
 This uses executeUpdate because the
SQL statement contained in
createTableCoffees is a data definition
language ( DDL ) statement
 DDL statements are executed with
executeUpdate
– Create a table
– Alter a table
– Drop a table
 executeUpdate is also used to execute
SQL statements that update a table

16. Execute Statements
 executeUpdate is used far more often
to update tables than to create them–
We create a table once but update it
many times
 The method used most often for
executing SQL statements is
executeQuery
 executeQuery is used to execute
SELECT statements – SELECT
statements are the most common SQL
statements

17. Entering Data to a Table
 Statement stmt = con.createStatement();
 stmt.executeUpdate ( "INSERT INTO COFFEES
" +
"VALUES ('Colombian', 101, 7.99, 0, 0)");
 stmt.executeUpdate ("INSERT INTO COFFEES "
+
"VALUES ('French_Roast', 49, 8.99, 0, 0)");
 stmt.executeUpdate ("INSERT INTO COFFEES "
+
"VALUES ('Espresso', 150, 9.99, 0, 0)");
 stmt.executeUpdate ("INSERT INTO COFFEES "
+
"VALUES ('Colombian Decaf' 101 8 99 0 0)");
 stmt.executeUpdate ("INSERT INTO COFFEES "
+

18. Batch Update
 What is batch update?
- Send multiple update statement in a
single request to the database
 Why batch update?
-Better performance
 How do we perform batch update?
-Statement.addBatch (sqlString);
- Statement.executeBatch();

19. 4.Get ResultSet
String queryStudent = "select * from Student";
ResultSet rs =
Stmt.executeQuery(queryStudent);
//What does this statement do?
while (rs.next()) {
int ssn = rs.getInt("SSN");
String name = rs.getString("NAME");
int marks = rs.getInt("MARKS");
}

20. 5. Close connection
 stmt.close();
 con.close();

21. Sample Program
import java.sql.*;
class TestThinApp {
public static void main (String args[])
throws ClassNotFoundException,
SQLException {
Class.forName("oracle.jdbc.driver.OracleDriver
");
// or you can use:
DriverManager.registerDriver(new
oracle.jdbc.driver.OracleDriver());
Connection conn =
DriverManager.getConnection(
"jdbc:oracle:thin:@localhost:1521:xe","scott","ti

22. Statement stmt = conn.createStatement( );
ResultSet rset = stmt.executeQuery(
"select 'Hello Thin driver tester '||USER||'!'
result from dual");
while(rset.next( ))
System.out.println(rset.getString(1));
rset.close( );
stmt.close( );
conn.close( );
}
}

23. SUMMARY
 JDBC makes it very easy to connect
to DBMS and to manipulate the data
in it.
 You have to install the oracle driver in
order to make the connection.
 It is crucial to setup PATH and
CLASSPATH properly

24. Thanks…..