1. Basics of JDBC
Session 14

2. Objectives Explain the concept of database connectivity Describe ODBC
Discuss what is JDBC
Discuss why we need JDBC
Describe the java.sql package in brief
Discuss types of drivers
Explain the anatomy of a JDBC program
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3. Database A database contains data that is in an organized form
Client/Server applications make extensive use of database programming
Activities may involve opening a connection, communicating with a database, executing SQL statements and retrieving query results
Standardized APIs are available that simplify database programming. Examples of these are ODBC and JDBC
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4. ODBC
Open DataBase Connectivity (ODBC) is an Application Programming Interface (API) provided by Microsoft for accessing databases
Provides functions to insert, modify and delete data and obtain information from the database
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5. How ODBC connection takes place?
Access
Driver
Access
Database
Oracle
Database
Application
ODBC
Interface
Driver
Manager
Oracle
Driver … …
Application could be a GUI program
Makes use of ODBC to interact with databases
Driver Manager is part of Microsoft ODBC and is used to manage various drivers in the system
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6. Need for JDBC ODBC uses a C interface that has lot of drawbacks
A literal translation of the ODBC C interface into a Java API would not be desirable
ODBC mixes simple and advanced features together and has complex options even for simple queries
A Java API like JDBC is needed in order to enable a “pure Java” solution
JDBC is portable
JDBC is a standard interface for Java programmers to access relational databases
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7. JDBC
JDBC is a Java Database Connectivity API that is a part of the Java Enterprise API
Defines a set of API objects and methods to interact with databases
JDBC is a must for all Java applications that access data stored in external data providers like SQL Server, Oracle or Access
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8. JDBC Driver Types (1) JDBC-ODBC Bridge plus ODBC Driver
ODBC is not readily convertible to Java
Sun provides a bridge driver to access ODBC data sources from JDBC
This is called the JDBC-ODBC Bridge plus ODBC driver
Database Server
Oracle
ODBC Driver
JDBC - ODBC bridge
Database Server
SQL Server
ODBC Driver
DB-client
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9. JDBC Driver (Java and Binary Code) Vendor Specific Protocol
JDBC Driver Types (2)
Native API partly-Java Driver
JDBC calls are converted into calls on the client API for DBMS
This driver uses JavaNativeInterface(JNI) that calls the local database APIs
The Native APIs partly-Java driver calls the Native Database Library that accesses the database
This driver like the ODBC driver needs binary code on the client machine
JDBC Driver (Java and Binary Code)
Vendor Specific Protocol
Database Server
DB-client
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10. Networking protocol & middleware
JDBC Driver Types (3)
JDBC-Net pure Java driver
Uses a networking protocol and middleware to communicate with the server
Server then translates the messages communicated to DBMS specific function calls
Specific protocol used depends on the vendor
No need for client installation
Allows access to multiple back-end databases
Database Server
Networking protocol & middleware
JDBC Driver (Pure Java Driver)
Database Server
SQL Server
DB-client
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11. Vendor Specific Protocol
JDBC Driver Types (4)
Native-protocol pure Java driver
100% Java enabled and does not use CLI libraries
Capable of communicating directly with the database
Converts JDBC calls into network protocols such as TCP/IP and other proprietary protocols used by DBMS directly
Since many of these protocols are proprietary, the database vendors themselves will be the primary source of usage
Vendor Specific Protocol
JDBC Driver
(Pure Java Driver)
Database Server
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DB-client

12. JDBC architecture (1) Java Program JDBC Driver SQL command Results
Application Server
Database
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13. JDBC architecture (2) The JDBC API interface comprises of two layers:
Application Layer – developer makes calls to database through SQL and retrieves results
Driver layer – handles all communication with a specific driver implementation
Four main Java interfaces that every Driver layer must implement are :
Driver, Connection, Statement and ResultSet
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14. Implements Interfaces
JDBC architecture (3)
Application layer
Driver layer
Implements Interfaces
Driver
Connection
Statement
ResultSet
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15. JDBC components
Application – here the JDBC methods are used to execute SQL and get results
Driver Manager – to load specific drivers for an application
Driver
Data Source – User application interacts with this to get results
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16. The java.sql package
JDBC API defines a set of interfaces and classes used for communicating with the database
These are contained in the java.sql package
Classes included in this package are :
Date, DriverManager, DriverPropertyInfo, Time, TimeStamp, Types
Interfaces included are :
Callable Statement, Connection, DatabaseMetaData, Driver, PreparedStatement, ResultSet, ResultSetMetaData, Statement
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17. Creating a JDBC application
Begin 1
Import the
java.sql package 2
Load and
Register the driver 3
Create a
Connection object 4
Create a
Statement object 5
Execute the
statement 6
Close Connection 7 8
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End

18. Example
Output
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19. Using SQL (1)
To retrieve the name, phone, and phone number from the table colleagues:
SELECT name, , phone FROM colleagues
To find out the number of employees who joined together on the same day and whose job_id is equal to 5:
SELECT count(*) FROM Employee WHERE job_id=5 GROUP BY hire_date
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20. Using SQL (2)
SQL DML statements do not return the results as ResultSets
Instead they return an integer representing the number of rows affected
Assume we need to add a new record –
INSERT into COFFEE VALUES(‘French_Roast’,00049,8.99,0,0)
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21. Using SQL (3)
The LIKE operator is used with SQL statements to compare two strings
SELECT * FROM employee WHERE emp_id LIKE ‘A%’
Data Definition Language statements are used to create tables, add columns to the existing tables; delete tables and so on
CREATE TABLE Emp(emp_name VARCHAR(25),emp_no VARCHAR(4),emp_age number);
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22. Example (1)
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23. Example (2)
Output
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