The document provides an overview of the Java Database Connectivity (JDBC) API. It discusses that JDBC allows Java applications to connect to relational databases and execute SQL statements. It describes the different types of JDBC drivers and the core JDBC classes like Connection, Statement, ResultSet, and their usage. The steps to connect to a database and execute queries using JDBC are outlined. Key concepts like processing result sets, handling errors, batch processing, stored procedures are also summarized.

1. JDBC API

2. Introduction
 JDBC is a set of programming APIs that allows easy
connection to a wide range of databases
 JDBC is a database-independent API for accessing
a relational database
 You pass SQL to Java methods in the JDBC classes
(the packages java.sql and javax.sql) and get back
JDBC objects
 JDBC is designed so simply that most database
programmers need learn only a few methods to
accomplish most of what they need to do

3. Types of Drivers
There are 4 types of JDBC Drivers
Type 1 - JDBC-ODBC Bridge
Type 2 - JDBC-Native Bridge
Type 3 - JDBC-Net Bridge
Type 4 - Direct JDBC Driver
Type 1 only runs on platforms where ODBC is available
ODBC must be configured separately
Type 2 Drivers map between a proprietary Database API and the
JDBC API
Type 3 Drivers are used with middleware products
Type 4 Drivers are written in Java
In most cases, type 4 drivers are preferred

4. Introduction
 java.sql provides the API for accessing and
processing data stored in a data source (usually a
relational database) using the Java programming
language
 this package provides classes and interfaces to get both
database and result set metadata from the database
server
 javax.sql provides the API for server-side data
source access
 This package supplements the java.sql package and, as
of the version 1.4 release, is included in the JDK

5. Architecture
 The DriverManager loads
JDBC drivers in memory, and
can also be used to create
java.sql.Connection objects
to data sources
 You can have more than one
driver and therefore more
than one database

6. JDBC Class Usage
DriverManager
Driver
Connection
Statement
ResultSet

7. Architecture
 DriverManager: It is a “factory” class and can
also be used to create java.sql.Connection
objects to data sources (such as Oracle,
MySQL, etc.).
 Connection: This interface represents a
connection with a data source. The Connection
object is used for creating Statement,
PreparedStatement, and CallableStatement
objects.
 DatabaseMetaData: This interface provides
detailed information about the database as a
whole. The Connection object is used for
creating DatabaseMetaData objects.
 Statement: This interface represents a static
SQL statement. It can be used to retrieve
ResultSet objects.
 PreparedStatement: This interface extends
Statement and represents a precompiled SQL
statement. It can be used to retrieve ResultSet
objects.

8. Architecture
 CallableStatement: This interface
represents a database stored
procedure. It can execute stored
procedures in a database server.
 ResultSet: This interface
represents a database result set
generated by using SQL’s SELECT
statement.
 ResultSetMetaData: This interface
provides information about the
types and properties of the
columns in a ResultSet object.
 SQLException: This class is an
exception class that provides
information on a database access
error or other errors.

9. JDBC Class Diagram
Copyright
©
1997
Alex
Chaffee
Whoa!

10. Data Types
Type JDBC Type JAVA Type
Suggested
Method
Boolean BIT boolean
Integer Data TINYINT byte
SMALLINT short getShort()
INTEGER int getInt()
BIGINT long
Floating-point
Data
REAL float
FLOAT
DOUBLE
double getDouble()
Binary Data BINARY
VARBINARY
LONGVARBINARY
byte[]
Textual Data CHAR
VARCHAR
LONGVARCHAR
String getString()
Date & Time DATE java.sql.Date getDate()
TIME
TIMESTAMP
java.sql.Time
java.sql.Timestamp
getTime()
getTimestamp()
Other types NUMERIC
DECIMAL
BigDecimal
CLOB Clob*
BLOB Blob*
ARRAY Array*
DISTINCT Mapping of
underlying type
STRUCT Struct*
REF Ref*
JAVA_OBJECT Underlying java class

11. Steps
 JDBC programming can be explained in the
following simple steps:
 Importing required packages
 Registering the JDBC drivers
 Opening a connection to a database
 Creating a
Statement/PreparedStatement/CallableStatement object
 Executing a SQL query and returning a ResultSet object
 Processing the ResultSet object
 Closing the ResultSet and Statement objects
 Closing the connection

12. Step 1: Import the Required Packages
 Before you can use the JDBC driver to get and use a
database connection, you must import the following
packages: java.sql and javax.sql.
import java.sql.*;
import javax.sql.*;

13. Step 2: Register the JDBC Drivers
 A JDBC driver is a set of database-specific
implementations for the interfaces defined by JDBC
 Oracle: First, the main driver class must be loaded
into the Java virtual machine (VM):
Class.forName("oracle.jdbc.driver.OracleDriver");
 The specified driver (i.e., the
oracle.jdbc.driver.OracleDriver class) must
implement the java.sql.Driver interface
 A class initializer (a static code block) within the
oracle.jdbc.driver.OracleDriver class registers the
driver with the java.sql.DriverManager

14. Step 2: Register the JDBC Drivers
 MySQL:
Class.forName("com.mysql.jdbc.Driver");
 A class initializer (a static code block) within the
com.mysql.jdbc.Driver class registers the driver with
the java.sql.DriverManager
 Note that when loading a JDBC driver, you must
make sure that the database-specific driver API
(usually a JAR file) is in your CLASSPATH
environment variable

15. Step 3: Opening a Connection to a Database
 Next, we need to obtain a connection to the database
 To get a connection object to a database, you need at
least three pieces of information: the database URL, the
database username, and the database user’s password
import java.sql.Connection;
import java.sql. DriverManager;
…
String dbURL =
"jdbc:oracle:thin:@localhost:1521:kitty";
String dbUsername = "scott";
String dbPassword = "tiger";
Connection conn =
DriverManager.getConnection(dbURL, dbUsername,
dbPassword);

16. Step 3: Opening a Connection to a Database
 There is an alternate method for creating a database connection: first get a
JDBC driver, then use that driver to get a connection
import java.sql.Connection;
import java.sql. Driver;
import java.sql. DriverManager;
import java.util.Properties;
…
String dbURL = "jdbc:oracle:thin:@localhost:1521:kitty";
String dbUsername = "scott";
String dbPassword = "tiger";
Properties dbProps = new Properties();
String driverName = "oracle.jdbc.driver.OracleDriver";
Driver jdbcDriver = (Driver)
Class.forName(driverName).newInstance();
dbProps.put("user", dbUsername);
dbProps.put("password", dbPassword);
Connection conn = jdbcDriver.connect(databaseURL, dbProps);

17. Step 3: Opening a Connection to a Database
 Once you have a valid java.sql.Connection object,
you can create statement objects (such as
Statement, PreparedStatement, and
CallableStatement)
Connection conn = <get-a-valid-Connection-object>;
Statement stmt = conn.createStatement();

18. Step 3: Opening a Connection to a Database
 Example Database
create table MyEmployees (
id INT PRIMARY KEY,
firstName VARCHAR(20),
lastName VARCHAR(20),
title VARCHAR(20),
salary INT
);
insert into MyEmployees(id, firstName, lastName, title, salary)
values(60, 'Bill', 'Russel', 'CTO', 980000);
insert into MyEmployees(id, firstName, lastName, title, salary)
values(70, 'Alex', 'Baldwin', 'Software Engineer', 88000);

19. Step 5: Executing a Query and Returning a
ResultSet Object
 Invoking the execute() method of the statement
object will execute the database-specific code
necessary to issue a SQL statement against the
database and retrieve the results (as a table)
String query = "SELECT id, lastName FROM
MyEmployees";
ResultSet result = stmt.executeQuery(query);
 The result is a table (as a ResultSet object) returned
by executing the SELECT statement
 By iterating the result, we can get all of the selected
records

20. Step 6: Processing the ResultSet Object
 ResultSet.next() returns a boolean: true if there is a
next row or record and false if not (meaning the end
of the data or set has been reached)
 Conceptually, a pointer or cursor is positioned just
before the first row when the ResultSet is obtained
 Invoking the next() method moves to the first row,
then the second, and so on

21. Step 6: Processing the ResultSet Object
 Once positioned at a row, the application can get the data on a
column-by-column basis using the appropriate ResultSet.getXXX()
method
if (rs.next()) {
String firstName = rs.getString(1);
String lastName = rs.getString(2);
String title = rs.getString(3);
int salary = rs.getInt(4);
}
or we may use the column names (instead of column positions):
if (rs.next()) {
String firstName = rs.getString("firstName");
String lastName = rs.getString("lastName");
String title = rs.getString("title");
int salary = rs.getInt("salary");
}

22. Step 7: Closing JDBC Objects
 Releasing or closing JDBC resources (such as
ResultSet, Statement, PreparedStatement, and
Connection objects) immediately instead of waiting
for it to happen on its own can improve the overall
performance
 From a good software engineering point of view, you
should put close() statements in a finally clause

23. Step 7: Closing JDBC Objects
 ResultSet has a close() method that releases the
ResultSet object’s database and JDBC resources
 Another major reason to close the ResultSet objects
immediately after they are done is that we increase
concurrency; as long as the ResultSet object is
open, the DBMS internally holds a lock

24. Step 7: Closing JDBC Objects
public static void close(java.sql.ResultSet rs) {
if (rs == null) {
return;
}
try {
rs.close();
// result set is closed now
}
catch(Exception ignore) {
// ignore the exception
// could not close the result set
// cannot do much here
}
}

25. Step 7: Closing JDBC Objects
public static void close(java.sql.Statement stmt) {
if (stmt == null) {
return;
}
try {
stmt.close();
// result set is closed now
}
catch(Exception ignore) {
// ignore the exception
// could not close the statement
// can not do much here
}
}

26. Step 7: Closing JDBC Objects
public static void close(java.sql.Connection conn) {
if (conn == null) {
return;
}
try {
if (!conn.isClosed()) {
// close the connection-object
conn.close();
}
// connection object is closed now
}
catch(Exception ignore) {
// ignore the exception
// could not close the connection-object
// can not do much here
}
}

27. JDBC Errors/Exceptions
 In JDBC, errors and exceptions are identified by the
java.sql.SQLException class (which extends the
java.lang.Exception class)
 SQLException is a checked exception
 Checked exceptions have to be caught (and handled
properly) or appear in a method that specifies in its
signature that it throws that kind of exception
 When a JDBC object (such as Connection,
Statement, or ResultSet) encounters a serious error,
it throws a SQLException

28. JDBC Errors/Exceptions
 JDBC give access to such information by providing
several levels of error conditions:
 SQLException: SQLException is an exception that
provides information on a database access error or other
errors.
 SQLWarning: SQLWarnings are subclasses of
SQLException, but they represent nonfatal errors or
unexpected conditions, and as such, can be ignored.
 BatchUpdateException: BatchUpdateException is an
exception thrown when an error occurs during a batch
update operation.
 DataTruncation: DataTruncation is an exception that
reports a DataTruncation warning (on reads) or throws a
DataTruncation exception (on writes) when JDBC
unexpectedly truncates a data value

29. Metadata
 DatabaseMetaData: Provides information about the
database as a whole.
 ResultSetMetaData: Used to identify the types and
properties of the columns in a ResultSet object.
 RowSetMetaData: An object that contains
information about the columns in a RowSet object.
 ParameterMetaData: An object that can be used to
get information about the types and properties of the
parameters in a PreparedStatement object.
 DriverPropertyInfo: Driver properties for making a
connection.

30. Example

31. More Details
 The important methods of Statement interface are as
follows:
1) public ResultSet executeQuery(String sql): is used to execute SELECT
query. It returns the object of ResultSet.
2) public int executeUpdate(String sql): is used to execute specified query, it
may be create, drop, insert, update, delete etc.
3) public boolean execute(String sql): is used to execute queries that may
return multiple results.
4) public int[] executeBatch(): is used to execute batch of commands.

32. More Details
 Example
import java.sql.*;
class FetchRecord{
public static void main(String args[])throws Exception{
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con=DriverManager.getConnection("jdbc:oracle:thin:@loc
alhost:1521:xe","system","oracle");
Statement stmt=con.createStatement();
//stmt.executeUpdate("insert into emp765 values(33,'Irfan',50000)");
//int result=stmt.executeUpdate("update emp765 set name='Vimal',sal
ary=10000 where id=33");
int result=stmt.executeUpdate("delete from emp765 where id=33");
System.out.println(result+" records affected"); con.close();
}
}

33. More Details
 ResultSet

34. More Details
 The PreparedStatement interface is a sub-interface
of Statement. It is used to execute parameterized
query.
 The important methods of PreparedStatement
interface are given below:

35. More Details
 Example
PreparedStatement stmt=con.prepareStatement("insert
into Emp values(?,?)");
stmt.setInt(1,101);
//1 specifies the first parameter in the query
stmt.setString(2,"Ratan");
int i=stmt.executeUpdate();
System.out.println(i+" records inserted");

36. More Details
 Example
PreparedStatement stmt=con.prepareStatement("update
emp set name=? where id=?");
stmt.setString(1,"Sonoo");
//1 specifies the first parameter in the query i.e. name
stmt.setInt(2,101);
int i=stmt.executeUpdate();
System.out.println(i+" records updated");

37. More Details
 Example
PreparedStatement stmt=con.prepareStatement("delete
from emp where id=?");
stmt.setInt(1,101);
int i=stmt.executeUpdate();
System.out.println(i+" records deleted");

38. More Details
 CallableStatement interface is used to call the
stored procedures and functions
 The differences between stored procedures and
functions are given below:

39. More Details
 Syntax
CallableStatement stmt=con.prepareCall("{call myproc
edure(?,?)}");

40. More Details
 Example
CallableStatement stmt=con.prepareCall("{call insertR(?,
?)}");
stmt.setInt(1,1011);
stmt.setString(2,"Amit");
stmt.execute(); create or replace procedure "INSERTR"
(id IN NUMBER, name IN VARCHAR2)
is
begin
insert into user420 values(id,name);
end;
/

41. More Details
 Example
CallableStatement stmt=con.prepareCall("{?= call sum4(?
,?)}");
stmt.setInt(2,10);
stmt.setInt(3,43);
stmt.registerOutParameter(1,Types.INTEGER);
stmt.execute();
create or replace function sum4
(n1 in number,n2 in number)
return number is temp number(8);
begin
temp :=n1+n2;
return temp;
end;
/

42. More Details
 Instead of executing a single query, we can execute
a batch (group) of queries.
 It makes the performance fast.
 The java.sql.Statement and
java.sql.PreparedStatement interfaces provide
methods for batch processing.
 The required methods for batch processing are given
below:

43. More Details
 Example
Statement stmt=con.createStatement();
stmt.addBatch("insert into user420 values(190,'abhi',40000
)");
stmt.addBatch("insert into user420 values(191,'umesh',500
00)");
stmt.executeBatch();
//executing the batch
con.commit();

44. More Details
 Example
PreparedStatement ps=con.prepareStatement("insert into user420 values(?,?,?
)");
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
while(true){
System.out.println("enter id"); String s1=br.readLine();
int id=Integer.parseInt(s1);
System.out.println("enter name"); String name=br.readLine();
System.out.println("enter salary"); String s3=br.readLine();
int salary=Integer.parseInt(s3);
ps.setInt(1,id); ps.setString(2,name); ps.setInt(3,salary);
ps.addBatch();
System.out.println("Want to add more records y/n");
String ans=br.readLine();
if(ans.equals("n")){ break; }
}
ps.executeBatch();

45. Thank You!
Questions?