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Simple Java Program to Acess books database.

Posted on 2009-05-05
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Last Modified: 2013-11-23
Write a simple java program to access the books database and display all the contents in the authors table.(Install MySql and the MySql-JDBC connector)
Heres the code I have but its for DIFFERENT TABLES. can you please correct the code for  program to access the books database and display all the contents in the authors table
1	// Fig. 25.25: DisplayAuthors.java
	2	// Displaying the contents of the authors table.
	3	import java.sql.Connection;
	4	import java.sql.Statement;
	5	import java.sql.DriverManager;
	6	import java.sql.ResultSet;
	7	import java.sql.ResultSetMetaData;
	8	import java.sql.SQLException;
	9	
	10	public class DisplayAuthors 
	11	{
	12	   // JDBC driver name and database URL                              
	13	   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";        
	14	   static final String DATABASE_URL = "jdbc:mysql://localhost/books";
	15	   
	16	   // launch the application
	17	   public static void main( String args[] )
	18	   {
	19	      Connection connection = null; // manages connection
	20	      Statement statement = null; // query statement
	21	    
	22	      // connect to database books and query database
	23	      try 
	24	      {
	25	         Class.forName( JDBC_DRIVER ); // load database driver class
	26	
	27	         // establish connection to database                              
	28	         connection =                                                     
	29	            DriverManager.getConnection( DATABASE_URL, "jhtp6", "jhtp6" );
	30	
	31	         // create Statement for querying database
	32	         statement = connection.createStatement();
	33	         
	34	         // query database                                        
	35	         ResultSet resultSet = statement.executeQuery(            
	36	            "SELECT authorID, firstName, lastName FROM authors" );
	37	         
	38	         // process query results
	39	         ResultSetMetaData metaData = resultSet.getMetaData();
	40	         int numberOfColumns = metaData.getColumnCount();     
	41	         System.out.println( "Authors Table of Books Database:" );
	42	         
	43	         for ( int i = 1; i <= numberOfColumns; i++ )
	44	            System.out.printf( "%-8s\t", metaData.getColumnName( i ) );
	45	         System.out.println();
	46	         
	47	         while ( resultSet.next() ) 
	48	         {
	49	            for ( int i = 1; i <= numberOfColumns; i++ )
	50	               System.out.printf( "%-8s\t", resultSet.getObject( i ) );
	51	            System.out.println();
	52	         } // end while
	53	      }  // end try
	54	      catch ( SQLException sqlException )                                
	55	      {                                                                  
	56	         sqlException.printStackTrace();
	57	         System.exit( 1 );                                               
	58	      } // end catch

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Question by:durrr
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12 Comments
 
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Expert Comment

by:Gibu George
ID: 24306556
This code looks ok.

>Heres the code I have but its for DIFFERENT TABLES
What does this mean?
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Expert Comment

by:Gibu George
ID: 24306575
One thing once the statement and rs are used close it. do that in the finally block and similarly once you are done with the connection object close that also
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Author Comment

by:durrr
ID: 24306983
I just got the Code from Deitel and Deitel Text Book but I was NOT sure if this code is right one for QUESTION i have posed. Can you please recheck if the answer to my question is the code I have incorporated. I thought  that the code is attached is for different query with different connection. Can you please re-check it thoroughly and tell me if this is the right code for my question. Thanks
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LVL 12

Expert Comment

by:Gibu George
ID: 24307045
The code which you have posted connects to a mysql db, gets the authorid, firstname,lastname from the authors table (all the rows). and dynamically goes through the result set and prints the authorid, firstname and last name row by row.

If you are having different tables, and connection details you just need to change the query. and the connection details like the url , user name, password.
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Expert Comment

by:Gibu George
ID: 24307055
if you want all the columns of the authors table
change the query to select * from authors,  this also will work
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Author Comment

by:durrr
ID: 24307174
Can you please Change it and post the updated Code, I dont wanna mess it up. Please bear with my ignorance, I am very new to all this programming. Please make the changes and attach the file. Thank you Gibu.
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Expert Comment

by:Gibu George
ID: 24307387
please find the attached code snippet, i hope the tables name is authors
// 25.25: DisplayAuthors.java
// Displaying the contents of the authors table.
import java.sql.Connection;
import java.sql.Statement;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
 
public class DisplayAuthors {
	// JDBC driver name and database URL
	static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
	static final String DATABASE_URL = "jdbc:mysql://localhost/books";
 
	// launch the application
	public static void main(String args[]) {
		Connection connection = null; // manages connection
		Statement statement = null; // query statement
 
		// connect to database books and query database
		try {
			Class.forName(JDBC_DRIVER); // load database driver class
 
			// establish connection to database
			connection = DriverManager.getConnection(DATABASE_URL, "jhtp6",
					"jhtp6");
 
			// create Statement for querying database
			statement = connection.createStatement();
 
			// query database
			ResultSet resultSet = statement
					.executeQuery("SELECT * FROM authors");
 
			// process query results
			ResultSetMetaData metaData = resultSet.getMetaData();
			int numberOfColumns = metaData.getColumnCount();
			System.out.println("Authors Table of Books Database:");
 
			for (int i = 1; i <= numberOfColumns; i++)
				System.out.printf("%-8s\t", metaData.getColumnName(i));
			System.out.println();
 
			while (resultSet.next()) {
				for (int i = 1; i <= numberOfColumns; i++)
					System.out.printf("%-8s\t", resultSet.getObject(i));
				System.out.println();
			} // end while
		} // end try
		catch (SQLException sqlException) {
			sqlException.printStackTrace();
			System.exit(1);
		} // end catch
		catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			if(connection!=null){
				try {
					connection.close();
				} catch (SQLException e) {
					connection=null;
				}
			}
		}
	}
}

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Author Comment

by:durrr
ID: 24307655
Got my question answered. Thanks Gibu
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Accepted Solution

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Gibu George earned 125 total points
ID: 24308521
Hi durr,

This is not the way to accept the solution, need to click accept the solution I have given closing this way

0
 
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Expert Comment

by:Gibu George
ID: 24308530
also deleting will not help others who are searching related solutions.
0
 
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Expert Comment

by:Gibu George
ID: 24308546
So please cancel the delete request and accept my comment as the solution
0
 

Author Comment

by:durrr
ID: 24309854
I did, thanks for letting me know.
0

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