Connection to the database and session

Friends I am developing a JSP based application ,and I am storing Connection (to the database) info in a session variable in my main menu , and then I retrieve the connection session in all the pages that I navigate to.
But a friend of mine told me it is not a good programming practice.He adviced me to use the connection pooling to make effecient use of the connection.
So using session for storing connection to the database is a bad idea ?
I thought it is bad idea to get connected to the database everytime a jsp is thrown ...hence I was using session variable.
Please give ur thought about this.
Thanks.

Well.
You are using a kind of connection pooling already, since you make a connection and reuse it along every jsp page in a session but reusability is at the cut&paste level here.
And what would you do if you needed to share a connection between sessions (scope:application)
Or how would you resolve the need to connect to 2 databases in one JSP page ?? Duplicate the code from the "main menu" ?
If you have let's say 5 applications written as you described and the connection data (ip address, SID, host) changes as someone moves the database to another machine (for example :-))) you will have to manually correct all 5 applications. So it's not much of flexibility in this kind of code.
Connection pooling as I understood it (I might be wrong :-))) is placing the code in a bean or servlet and the parameters in a txt (or better xml) file so when something changes you don't rewrite applications, just rewrite one txt (xml) file and you are done.
If you use a connection pool as a bean you have the bean scopes you can choose from and so on.....
Visit
http://www.codestudio.com/index.shtml
for an example of a very well written connection pool. Maybe there you will find other issues to help you decide.
Hope this helps!
Bye

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Itext connect to the database and put values in a table

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How does it connect to the database

can anyone pls tell me how the below coding connect to the database, and if i want to change to use other type of connection, which part of the coding should i use? thank
loginAction.jsp
<%@ page contentType="text/html; charset=iso-8859-1" language="java" import="java.sql.*" errorPage="" %>
<html>
<head>

<title>Untitled Document</title>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<LINK href="bios.css" type=text/css rel=stylesheet>

</head>
<body leftmargin="0" topmargin="0">
<%@ include file="useAndImport.jsp" %>
<%
String username = (String)session.getAttribute("username");
session.setMaxInactiveInterval(10*60);
boolean isLoggedIn=work.isUsable(username)?true:false;
%>
<table width="100%" height="22" border="0" cellpadding="0" cellspacing="0" bgcolor="#CC3300" class="statusloginsearch">
<tr>
          <SCRIPT LANGUAGE="JavaScript">





</script>
<form action=loginAction.jsp method=POST>
<td width="77%" valign="baseline" nowrap id="statusbar"> <% if (isLoggedIn)
out.println("<img src=images/active.gif width=10 height=15 align=middle><font size=1 color=white face=Verdana, Arial, Helvetica, sans-serif><b>Welcome, " + username + " </b></font>");%> <% if (!isLoggedIn) { %>
<font color="#FFFFFF" size="1" face="Verdana, Arial, Helvetica, sans-serif">Username:</font><font size="1" face="Verdana, Arial, Helvetica, sans-serif">
<input type=text name=username class="form" <%= work.getValueAttribute(username) %> >
<font color="#FFFFFF"> Password:</font>
<input type=password name=password class="form">
<input type="submit" name="action" value="Login" class="formbutton" onfocus="this.blur()" onmouseover="this.className='formbuttonover';" onmouseout="this.className='formbutton';" onmousedown="this.className='formbuttonover';" onmouseup="this.className='formbuttonover';">
<input type="reset" name="action" value="Reset" class="formbutton" onfocus="this.blur()" onmouseover="this.className='formbuttonover';" onmouseout="this.className='formbutton';" onmousedown="this.className='formbuttonover';" onmouseup="this.className='formbuttonover';">
<img src="images/question.gif" alt="what's this?" width="15" height="15" border="0" align="middle">
<% } %>
</font></td>
</form>
<td width="23%" valign="baseline" nowrap id="statusbar"> <div align="right">
<% if (isLoggedIn)
out.println("<form action=SignOut.jsp method=POST><input type=submit name=action value=Logout class=formbutton onfocus=this.blur() onmouseover=this.className='formbuttonover'; onmouseout=this.className='formbutton'; onmousedown=this.className='formbuttonover'; onmouseup=this.className='formbuttonover';></form> <a href=tour.jsp><img src=images/newtothissite.gif border=0 align=middle></a>");%>
  </div></td>
</tr>
</table>
<table width="650" border="0" cellspacing="4" cellpadding="1">
<tr>
<td>
<table width="580" border="0">
<tr>
<td><strong><font color="#CCCCCC" size="+2" face="Arial, Helvetica, sans-serif">ERROR</font></strong></td>
</tr>
</table>
<%-- loginAction.jsp --%>
<%
String username1 = request.getParameter("username");
String password=request.getParameter("password");
boolean isUsername=work.isUsable(username1);
boolean isPassword=work.isUsable(password);
String usernameQuoted=work.getSingleQuoted(username1);
String usernameParam = work.makeUrlParameter("username",username1);
ResultSet resultset;
if(isUsername && isPassword) {
resultset=db.executeQuery
("SELECT * FROM users WHERE USERNAME = " + usernameQuoted);
if (resultset.next() &&
resultset.getString("password").equals(password))
out.println("<font color=green>You are logged on.</font>");
session.setAttribute("username", username1);
String accessLevel = resultset.getString("access_level");
     session.setAttribute("access", accessLevel);
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     response.sendRedirect("Welcome.jsp");
     else if(accessLevel.equals("3"))
     response.sendRedirect("Admin.jsp");
%>
<%
} else {
out.print(work.tryAgain(
"<font size=2 color=red face=Verdana, Arial, Helvetica, sans-serif><b>Your username and/or password are incorrect.</b>",
"Login.jsp"+usernameParam));
} else {
out.print(work.tryAgain(
"<font size=2 color=red face=Verdana, Arial, Helvetica, sans-serif><b>Your login information is incomplete.",
"Login.jsp"+usernameParam));
%>

</td>
</tr>
</table>
</body>
</html>
useAndImport.jsp
<%-- thingsToUseAndImport.jsp --%>
<jsp:useBean id="db"
class="kw.search.DbAccess"
scope="application"/>
<jsp:useBean id="work"
class="kw.search.Worker"
scope="application"/>
<jsp:useBean id="dataB"
class="bb.messageBoard.DataB"
scope="application"/>
<jsp:useBean id="forum"
class="bb.messageBoard.Forum"
scope="application"/>
<%@ page import="java.text.DateFormat, java.util.Vector, java.io.*" %>
DbAccess.java
package kw.search;
import java.sql.*;
public class DbAccess implements java.io.Serializable {
private Connection connection;
private Statement statement;
String db = "btc";
String user = "javauser";
String password = "javauser";
String dbUrl = "jdbc:mysql://localhost:3306/" +db;
//dbUrl = "jdbc:mysql://localhost:3306/"+db;
public DbAccess ()
throws ClassNotFoundException, SQLException
Class.forName("com.mysql.jdbc.Driver");
//connection = DriverManager.getConnection ("jdbc:mysql://localhost:3306/btc?"+"user=javauser&password=javauser");
connection = DriverManager.getConnection
(dbUrl+"?user="+user+"&password="+password);
connection.setAutoCommit(false);
statement = connection.createStatement();
public void executeUpdate(String sqlCommand)
throws SQLException
statement.executeUpdate(sqlCommand);
public ResultSet executeQuery(String sqlCommand)
throws SQLException
return statement.executeQuery(sqlCommand);
public void commit() throws SQLException
connection.commit();
public void rollback() throws SQLException
connection.rollback();
protected void finalize() throws SQLException
statement.close();
connection.close();
}

This section of your code makes the connection:
public DbAccess ()
throws ClassNotFoundException, SQLException
Class.forName("com.mysql.jdbc.Driver");
//connection = DriverManager.getConnection ("jdbc:mysql://localhost:3306/btc?"+"user=javauser&password=javauser");
connection = DriverManager.getConnection
(dbUrl+"?user="+user+"&password="+password);
connection.setAutoCommit(false);
statement = connection.createStatement();
public void executeUpdate(String sqlCommand)
throws SQLException
statement.executeUpdate(sqlCommand);
public ResultSet executeQuery(String sqlCommand)
throws SQLException
return statement.executeQuery(sqlCommand);
public void commit() throws SQLException
connection.commit();
public void rollback() throws SQLException
connection.rollback();
}

RDA ---Can not connect to the database

Folks,
I am trying to generate an RDA output for ORACLE SUPPORT
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Server: Win 32bit SP1
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STEP2: run rda.cmd to generate output
at this time it asks me the password of the system username as sysdba and errors out saying
the following
Processing Initialization module ...
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If you choose to continue without database connection, some information will
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Press 'Enter' to Continue
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Has anyone encountered this issue

Well, I'm not sure if Oracle can't even figure it out. I found this in a connection troubleshooting guide specific to windows....maybe give these a try just to verify again.
Troubleshooting Steps Common to Unix and Windows
Connection Issues
If RDA is unable to connect to the database, and the user is declared as a SYSDBA user when running the setup, ensure that a connection is possible with as the user using AS SYSDBA. For example, if SYSTEM is specified as the username, make sure that you can connect using the following command in sqlplus:
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If you cannot connect, run the setup again and answer N to that question, or edit the setup file (setup.cfg) and set SYSDBA_USER=0. You can also use the 'TSTdb' test module to obtain more elements on the connection problem. This test can be performed using the following command(s):
For Windows run:
rda.cmd -T TSTdb or rda.pl -T TSTdb
For Unix run:
rda.sh -T TSTdb or rda.pl -T TSTdb
If you use TWO_TASK enviroment variable is used to connect to the database, then unset TWO_TASK and run RDA on the server local to the database. This is necessary because RDA depends on a local connection to the database, and automatically unsets TWO_TASK before performing any function.
Edited by: DBA_Mike on Mar 25, 2009 5:37 AM

How to create a link to a web page that is connected to the database?

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Its really hard to answer this question with this enough information....Which Jdeveloper version? which technology you are using to create this web form ? ADF BC or others
If 11g then are you aware of Task flows?

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Hi all,
I am trying to configure Hyperion Planning, i am getting error while connection to the database,
and i am not able to connect to the sqlserver management studio using sql server authentication mode, while installing sql server i selected as windows authentication mode,
here is my environment:
OS: Windows Vista
Database: MS SQL Server 2005, with Windows authentication mode
Hyperion9.3.1: Planning, Essbase server, shared services.
can anyone let me know what is the error? or do am i missing any step,
appreciate your help.
Thanks
Afjal

Hi,
First of all Vista is not supported as O/S for Hyperion server products, so if you encounter any problems it may be due to that.
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It is possible to change SQL server to mixed mode.
Cheers
John
http://john-goodwin.blogspot.com/

I want to know the ways of connecting 9iAS to Database and clients to database through 9iAS as middleware.

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Hi ,
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Connect to the database of auto Hosted App on Office 365

Hi All,
I developed a custom Application for SharePoint on top Office 365 in Auto-hosted mode. The application has SQL database which will be deployed to SQL Azure.
I would like to read some info from the database but using another tools not from inside the developed application (e.g. SharePoint designer, PowerPivot) to generate some reports.
When I try to connect to the database after the application installation using SharePoint Designer I get the following error message:
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Hi m_3ryan,
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http://azure-howto.blogspot.com/2011/05/how-to-set-firewall-rule-to-connect-to.html
Thanks,
Qiao
Forum Support
Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact
[email protected]
Qiao Wei
TechNet Community Support

Best Practice for closing a blocking connection to the database.

Background:
Using toplink/eclipselink to manage the the connection to the database.
We support 3 databases, Oracle, Mysql, and MSSQL.
We host the an application locally (SAAS) and we also distribute it to our clients so they can run it on premise.
Problem:
From time to time the application will execute a route that query the DB and will take 10+ minutes. When we find these queries we generally fix them, but it takes time to fix the problem and roll new code to production. We have also found that if an end user executes the query to many times they can potentially bring the service down - maxing out the database connection, or putting a huge load on the DB effectively rendering the system to a crawl.
During this time period the IT team need a way to abort a transaction. The current approach, for our SAAS solution, to scan the database find to the long running query and kill it. The application is smart enough to recover and everything seems to work fine. This doesn't always work for our on premise customers - often they don't have a DBA or adequate resources to monitor the system. Therefore, I'm looking for a way to have the application kill/close any query that is lasting longer then X minutes. We currently track the duration of every thread so I can get the time the thread has been actively running.
Stack Trace
Currently we keep track of how long each thread is running waiting for a response from the database such as the stacktrace below, I would like to grab the connection and physically close it. Since we are using a java socket and it's in a blocking state there is no way for us to interrupt the thread. The only option is to wait for it to receive a response from the db - kill the sql process - or to close the java socket.
java.net.SocketInputStream.socketRead0(Native Method)
java.net.SocketInputStream.read(SocketInputStream.java:129)
com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
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com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2909)
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com.mysql.jdbc.Connection.execSQL(Connection.java:2998)
com.mysql.jdbc.Connection.execSQL(Connection.java:2927)
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org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeSelect(DatabaseAccessor.java:854)
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org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:501)
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org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeSelectCall(DatasourceCallQueryMechanism.java:262)
org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeSelect(DatasourceCallQueryMechanism.java:244)
org.eclipse.persistence.queries.DataReadQuery.executeNonCursor(DataReadQuery.java:188)
org.eclipse.persistence.queries.DataReadQuery.executeDatabaseQuery(DataReadQuery.java:144)
org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:664)
org.eclipse.persistence.queries.DataReadQuery.execute(DataReadQuery.java:130)
org.eclipse.persistence.internal.sessions.AbstractSession.internalExecuteQuery(AbstractSession.java:2243)
org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1181)
org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1165)
org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1125)
Question
What is the best way to grab the connection and close it - from another thread?

The reason for changing the namespace is to guarantee that they appear as different versions. The namespace is part of the strong name of the DLL when deployed. Yes they will be deployed to separate servers because a server can only belong
to one farm. But when you are doing a migration it won't be clear that you need to install the 2013 version since the .DLL will report that it exists in the 2010 farm already. It will work without changing the namespace, but it would be best to differentiate
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Paul Stork SharePoint Server MVP
Principal Architect: Blue Chip Consulting Group
Blog: http://dontpapanic.com/blog
Twitter: Follow @pstork
Please remember to mark your question as "answered" if this solves your problem.

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Is there something else that can be done to speed up the execution of the page?
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Thank you all for your input I was trying to work this project to learn JSP so I am not looking at purchasing any drivers right now. That is the reason why I stuck to the JDBC-ODBC Bridge. Are there any other drivers available for MS SQL Servers that are free.
Jschell,
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Sorry if this is a trivial question. I have been a Java developer for years. But just starting developing webapps using JSF.
Thanks

JuCobb2 wrote:
I am then storing the connection to the database in a backing bean. Hoping to use this connection throughout the session. Is this a good practice to have a users connection left open over the session? No it is not. Why should you do so? Always keep the lifetime of connection, statement and resultset as short as possible.

Connect to the database straight from the direct access of form builder

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Thanks anyway-

Using only 1 connection to the database

I have to use TopLink to connect to an Access database using the JDBC-ODBC bridge (please don't ask). The problem is that I can only create 1 connection to the database (as the bridge doesn't allow concurrent connections).
How can I tell TopLink to share the only connection I have for reading and writing?
I have tried setting the number of connection to 1 and using exclusive read but it allways create 1 to read and one to write...
help?
jeremie

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10g Enterprise Manager is not able to connect to the database instance

I am running a Oracle 10g database in Solaris 10 server. When i am trying to connect to the enterprise manager it says Enterprise Manager is not able to connect to the database instance.
The database instance is open,the listener is up and the agent connection also says that it succeeded.
The server houses two 10g databases and the EM was working properly till yesterday. Kindly Help.
Thanks in advance.
Ram

Hi,
The EM is started and if i give emctl status dbconsole
-bash-3.00$ emctl status dbconsole
Oracle Enterprise Manager 10g Database Control Release 10.2.0.3.0
Copyright (c) 1996, 2006 Oracle Corporation. All rights reserved.
http://gladiator:1158/em/console/aboutApplication
Oracle Enterprise Manager 10g is running
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it says that the EM is running. But when i am trying to access the URL it is in IE it says Page cannot be displayed what could be the problem for this???
Thanks in advance.
Ram

SAP Server has lost connection to the database!

Hi Gurus,
Can some please guide me on this " SAP Server has lost connection to the database! " what need to be check.
OS : AIX
DB : DB2
thanks
vamsi

Hello,
1)Check if the DB is running.Issue the following command @ the DB-level
db2 connect to <SID>.
2)Also check R3trans -d from the app. server and check for trans.log file for the error.
Hope it helps.
Regards,
Prasanna
Edited by: Kulkarni Prasanna on Jul 24, 2008 3:53 PM

Connection to the database and session

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