Getting started with JDBC

JDBC know as Java Database Connectivityprovides set of api or standard library for accessing relational databases. Java programs interact with any SQL-compliant database using this api.

JDBC API achieve following tasks:

• Allow to establish connection with supported database
• Sql Query creation
• Method to create and execute stored queries
• Metadata look up

JDBC Architecture:

The JDBC API supports both three-tier and two-tier models for database access but consists of two layers:

• JDBC API: This allows connection between application and JDBC Manager.
• JDBC Driver API: This allows Driver Connection to JDBC Manager.

The JDBC API uses drivers which are database-specific and driver manager to provide connectivity to databases.

The JDBC driver manager communicates with vendor-specific driver that performs real communication with database.

JDBC-ODBC Bridge plus ODBC Driver (Type 1): Driver use ODBC driver to connect to database servers.

Native API partly Java technology-enabled driver (Type 2): Driver converts JDBC class to client API for the RDBMS server.

Pure Java Driver for Database Middleware (Type 3): Driver sends the JDBC calls to  middleware server to connect different type of databases.

Direct-to-Database Pure Java Driver (Type 4): Driver allows the JDBC calls over the network protocol using the database server.

Common JDBC Components:

The JDBC API has following classes and interfaces:

• Driver Manager:Database drivers list are managed by this class.
• Driver:It is an Interface to communicatewith database server.
• Connection :It is an interface having all methods for contacting with database
• Statement:The objects created interface to SQL statements to database.
• ResultSet:The objects holds data retrieved from database after executing SQL query Statement objects.
• SQLException: The class handles any errors occurring in database application.

The JDBC 4.1 Packages

The JDBC 4.1 is a primary package which includes java.sql and javax.sql. 

New features in 4.1 includes 

• The ability to automatically close resources of type Connection, ResultSet, and Statement with try-with-resources statement.
• RowSet 1.1: The introduction of the RowSetFactory interface and the RowSetProvider class, which enable you to create all types of row sets supported by your JDBC driver.