How To Connect Database In Java?

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For connecting a database with the application 5 steps are given -
1) Register the driver class
2) Creating connection
3)Creating statement
4)Executing queries
5) Closing connection
1) Register the driver class
To register the driver class forName() method of Class class is used. This method is mainly used to dynamically load the driver class.
Syntax :
public static void forName(String className)throws
ClassNotFoundException

Example to register the Oracle driver class :

1. Class.forName("oracle.jdbc.driver.OracleDriver");
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2) Create connection object
To establish connection with the database getConnection() method of DriverManager class is used.
Syntax :
1. 1) public static Connection getConnection(String url)throws SQLException
2. 2) public static Connection getConnection(String url,String name,
3. String password) throws SQLException
Example to establish connection with the Oracle database
1. Connection con=DriverManager.getConnection
2. ...
... ( "jdbc:oracle:thin:@localhost:1521:xe","system","password");
3) Create Statement object
To create statement object The createStatement() method of Connection interface is used. The object of statement is mainly used to execute queries with the database. Advanced java training in bangalore

1. Syntax : public Statement createStatement()throws SQLException
Example to create the statement object
1. Statement stmt=con.createStatement();
4) Execute the query
To execute queries to the database executeQuery() method of Statement interface is used. This method returns the object of ResultSet that can be used to get all the records of a table.
Syntax of executeQuery() method
1. public ResultSet executeQuery(String sql)throws SQLException
Example to execute query
1. ResultSet rs=stmt.executeQuery("select * from emp");
2.
3. while(rs.next()){
4. System.out.println(rs.getInt(1)+" "+rs.getString(2));
5. }
5) Close the connection object
By closing connection object statement and ResultSet will be closed automatically. The close() method of Connection interface is used to close java course in Bangalore the connection.

Syntax :
public void close()throws SQLException
Example to close connection
con.close();
Connection with Oracle database :
To connect java application with the oracle database, we need to follow 5 steps to perform database connectivity. Before that some information is needed :
1. Driver class: The driver class for the oracle database is oracle.jdbc.driver.OracleDriver.
2. Connection URL: The connection URL for the oracle database is jdbc:oracle:thin:@localhost:1521:xe where jdbc is the API, oracle is the database, thin is the driver, localhost is the server name on which oracle is running, , 1521 is the port number and XE is the Oracle service name. Username: The default username for the oracle database is system. Java course in Bangalore
3. Password: Password is given by the user at the time of installing the oracle database.
Steps :
1. step1 : load the driver class
2. Class.forName("oracle.jdbc.driver.OracleDriver");
1. step2: create the connection object
2. Connection con=DriverManager.getConnection
3. ( "jdbc:oracle:thin:@localhost:1521:xe","system","oracle");
4.
5. step3: create the statement object
6. Statement stmt=con.createStatement();
7.
8. step4: execute query
9. ResultSet rs=stmt.executeQuery("select * from emp");
while(rs.next())
System.out.println(rs.getInt(1)+" "+rs.getString(2)+" "+rs.getString(3));
10.
step5: close the connection object
11. con.close();
What is JDBC Drivers ? best core java training in bangalore
JDBC Driver is a software component that enables java application to interact with the database. There are 4 types of JDBC drivers:
1. JDBC-ODBC bridge driver
2. Native-API driver (partially java driver)
3. Network Protocol driver (fully java driver)
4. Thin driver (fully java driver)
1) JDBC-ODBC bridge driver
The JDBC-ODBC bridge driver uses ODBC driver to connect to the database. The JDBC-ODBC bridge driver converts JDBC method calls into the ODBC function calls. This is now discouraged because of thin driver.
2) Native-API driver
The Native API driver uses the client-side libraries of the database. The driver converts JDBC method calls into native calls of the database API. It is not written entirely in java.
3) Network Protocol driver
The Network Protocol driver uses middleware (application server) that converts JDBC calls directly or indirectly into the vendor-specific database protocol. It is fully written in java. Core and advanced java institute in marathahalli
4) Thin driver
The thin driver converts JDBC calls directly into the vendor-specific database protocol. That is why it is known as thin driver. It is fully written in Java language.
3. This is the short description about the JDBC connectivity . To get the more knowledge on java for getting a job as java developer join Infocampus Software Training Institute .

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