Java JDBC Tutorial
Java JDBC Tutorial
The JDBC ( Java Database Connectivity) API defines interfaces and classes for writing database applications in Java by making database connections. Using JDBC you can send SQL, PL/SQL statements to almost any relational database. JDBC is a Java API for executing SQL statements and supports basic SQL functionality. It provides RDBMS access by allowing you to embed SQL inside Java code. Because Java can run on a thin client, applets embedded in Web pages can contain downloadable JDBC code to enable remote database access. You will learn how to create a table, insert values into it, query the table, retrieve results, and update the table with the help of a JDBC Program example.
Although JDBC was designed specifically to provide a Java interface to relational databases, you may find that you need to write Java code to access non-relational databases as well.
Java application calls the JDBC library. JDBC loads a driver which talks to the database. We can change database engines without changing database code.
JDBC Basics - Java Database Connectivity Steps
Before you can create a java jdbc connection to the database, you must first import the
import java.sql.*; The star ( * ) indicates that all of the classes in the package java.sql are to be imported.
1. Loading a database driver,
In this step of the jdbc connection process, we load the driver class by calling Class.forName() with the Driver class name as an argument. Once loaded, the Driver class creates an instance of itself. A client can connect to Database Server through JDBC Driver. Since most of the Database servers support ODBC driver therefore JDBC-ODBC Bridge driver is commonly used.
The return type of the Class.forName (String ClassName) method is “Class”. Class is a class in
Class.forName(”sun.jdbc.odbc.JdbcOdbcDriver”); //Or any other driver
System.out.println( “Unable to load the driver class!” );
2. Creating a oracle jdbc Connection
The JDBC DriverManager class defines objects which can connect Java applications to a JDBC driver. DriverManager is considered the backbone of JDBC architecture. DriverManager class manages the JDBC drivers that are installed on the system. Its getConnection() method is used to establish a connection to a database. It uses a username, password, and a jdbc url to establish a connection to the database and returns a connection object. A jdbc Connection represents a session/connection with a specific database. Within the context of a Connection, SQL, PL/SQL statements are executed and results are returned. An application can have one or more connections with a single database, or it can have many connections with different databases. A Connection object provides metadata i.e. information about the database, tables, and fields. It also contains methods to deal with transactions.
JDBC URL Syntax:: jdbc: <subprotocol>: <subname>
JDBC URL Example
:: jdbc: <subprotocol>: <subname>•Each driver