Multiple sessions in a single database connection.

I have copied the following text from Forms Developer2000
"At runtime, Form Builder automatically establishes and manages a single connection to ORACLE. By default, one user session is created for this connection. However, the multiple-sessioning feature of ORACLE allows a single client to establish multiple sessions within a single connection. ORACLE transaction-management and read-consistency features all are implemented at the session level, so creating multiple sessions allows a single user to have multiple, independent transactions."
If ORACLE allows a single client to establish multiple sessions within a single connection, I want to leverage on this feature in my application which uses BC4J.
Can anybody tell me if
1. its possible achieve this in Java(BC4J).
2. If Yes, How?
regards,
vikrant

Thank you for your valuable suggestion.
I believe createing multiple root Application
Modules, will create as many number of connections to
database, hence multiple transactions.
But What I wanted was multiple sessions in a single
connection, who's behavior will be similar to two
different connections.Could you tell me the advantage you're looking for in multiple sessions in one connection vs. multiple connections (where connections may be pooled)?
Thanks.
Sung

Similar Messages

Can i use single database connection in a hole java application?

can i use single database connection in a hole java application?.I have so many forms to use database connection.

Theoretically you can. Not only theoretically. I've seen lots of application which only uses one database connection (they were using, oracle or mysql)
The first reply given here assumed that the answer to
your question depends only on the design of your
application. That is not true.Yes it's true. Nothing in the original questions says that you aren't allowed to open or close the single connection that you have. It's looks more like the OP is interested in sharing a connection (i.e having a singleton or a connection pool with only one connection)
It does also depend on the behaviour of the database
in the background.
Most databases have a time out for connections that
are idle Not a problem. Most implementations of connection pools and applications which keeps a connection open have a timer which calls e.g. select * from dual (if you are using oracle) when the connection has been idle for X minutes.
(some, like db2 on z/OS, even cancel
connections, that are not idle, if they are open a
certain amount of time or have reached a given limit
of cpu seconds.)You would also have that problem if you had a connection pool with several connections.
In essence: If you have no control over the time
your application runs (and therefore your connection
is open) or over type or the configuration of the
database you are accessing, you can't do it.See above.
The closest thing to what you want would be using
PooledConnections, iif those are supported for the
database you want to access.Not true.
Kaj

Multiple Import into Multiple schemas in a single Database server ?

Is it possible to create a multiple import into multiple schema in a single DB server ?

Hi,
Yes, You can do it.. With Multiple Export File..it may cause some Performance issue, so need to check your Server configuration before do that..

Single database connection/detecting disconnect

I receive an error when attempting to connect to the database after the database had gone down and was subsequently brought back up. The code checks to see if the connection 'isClosed' but this method seems to fail under these circumstances. The solution is to re-start the Apache server and log on. Is there a fix to prevent the error message? The connection is created by the first person to login and is maintained through subsequent database requests.
Below is code to test for an existing connection......
public Stuff[] getStuff() throws DBException {
try { synchronized(dbConn) {
if(dbConn.isClosed()) { this.dbInit(); }
//etc,etc,etc
Below is code for dbInit method.......
private void dbInit()     throws DBException {
String getStuff="SELECT * from tbl WHERE uname = ?";
try {
Class.forName(driverName);
dbConn = DriverManager.getConnectio(dUrl,user,pass);
getUserStmt = dbConn.prepareStatement(getStuff);
catch (ClassNotFoundException     exc) {
throw new DBException("No Driver Available!")}
catch     (SQLException exc) {
throw new DBException(exc.getMessage());}

Depending on what DB platform and driver version you're running on I think your best bet is to have Apache create a DB connection pool and have your app pull from the pool. That way Apache always creates the pool on startup and checks the state of connections periodically. Unless you reach the maximum number of connections allowed by security or DB platform you should always have a connection.

Single database connection create and using all programs jsp and servlet

Hai
i am create databaset connection using that all programs how to implement

Post the steps you managed already. If you don't know anything about how to receive data from a database try this link:
http://java.sun.com/docs/books/tutorial/jdbc/index.html

Multiple MDM Servers on Single Database ?

Hi MDM Experts,
Please shed some light on the following questions:
Is it possible to have two or more MDM Servers use the same database server ?
If so then what are the kind of conflicts expected ?
Thanks in advance,
Uday

Hi Uday,
Is it possible to have two or more MDM Servers use the same database server ?
Yes, you can use the two and more MDM Servers for the Same DataBase Server
If so then what are the kind of conflicts expected ?
then Problem of Appropriate Repository come into Picture
For More Details Refer:
http://help.sap.com/saphelp_mdm550/helpdata/en/8e/9f9c427055c66ae10000000a155106/frameset.htm ---> Navigate to Repository Administration ---> then to Appropriating an MDM Repository
Rewards if Useful,
Hope it will help you,
Mandeep Saini

Multiple EBS env's - single database

Hi,
Can we have EBS environments of EBS sharing the same database. I haven't tried this before , but I think this might be possible. But defintely if possible would be a very complex architecture.
Has anyone tried this before? Does this really work?
If it work, can you please suggest me a procedure how this can be done.

Are you asking if various EBS environments (like Dev, Test, Prod etc) can all share the same database ? If that is what you are asking, then the answer is no. Each EBS environment requires its own database.
Srini

ODI database connection - session question

Hi,
I have a package, where I have used a procedure.
In my procedure, I open a database connection.
My question is - In my next procedure - will I be able to use my same database connection which I created in previous step?
Re-phrasing the question - for any number of database transaction happening in a package, will ODI opens multiple database connection per step or will there be only one single database connection?
Thank you,
Paras

I believe its one per session so one connection inside the package. I think you should be , although i have not tried it practically.

Multiple instances operated on a single database on a single machine

Hi friends,
Can anybody tell that "Is it possible to operate multiple instances on a single database on a single machine"!?.
If so.., where this case is useful.
Please help on this doubt.
Thanks in advance.
Thanks
Srinivasa Rao

Hi,
I just asked whether it is possible or not. It is not much important. As you said, OPS will perform well if instances are on different machines. I agree on this. But I think we need to replicate the database on other machine also to run fast.Am I right?..If not, please correct me...
Thanks for valuable information.
I just re-read your post. When you say multiple instances on a single database, it sounds to me like you are asking about Oracle Parallel Server in 8i. I don't know why you would (or even if you could) have multiple instances on the same box. I don't think that would make sense since on of the benefits of OPS is to have more processing power by using multiple machines.

MULTIPLE SESSIONS IN SINGLE FORM

HELLO ALL
HOW CAN I HAVE MULTIPLE SESSIONS IN A SINGLE FORM? MY REQUIRMENT
IS SUCH THAT I HAVE A CONTROL BLOCK WHICH IS MARKED AS UPDATED
WHEN USER PRESS COMMIT BUTTON, BUT I WANT TO ROLL IT BACK AND I
HAVE ISSUED SOME UPDATE COMMANDS MYSELF WHICH I WANT TO BE
COMMITED. ANYONE HAVE ANY IDEA?
THANKS IN ADVANCE

Give the submit button a name. It will be sent as well, so you can see it in the request variables.

KIMYONG : Applications Database Connection Pool 관련 parameter 설명

Purpose
JVM 이 과도한 CPU / Memory를 사용하게 되어 Application Performance에 영향을 미칠때가 있으며 이럴경우 Connection Pool 관련하여 Parameter Tunning을 해야 할때가 있습니다. 이때 사용되는 Parameter들의 의미를 설명하고자 합니다.
The Applications Database Connection Pool is a pool of JDBC database connections that are shared among java applications. Applications obtain connections from the pool by using the getJDBCConnection(...) methods of AppsContext.
Essentially, each AppsContext has a single database connection associated with it at all times.
The AOL/J layer internally borrows and returns this connection to the pool as needed to maintain connection reference that is properly initialized for the current Java tier AOL security context and NLS state.
FND_MAX_JDBC_CONNECTIONS
============================
The maximum pool size is the maximum allowed sum of the number of available connections and thenumber of locked connections. If the pool reaches the maximum size and all connections are locked, new clients will not be able to borrow a connection until one of the current clients has returned one. The default setting for this parameter is essentially unlimited (about 2 billion).
FND_JDBC_BUFFER_MIN
======================
The buffer minimum is the minimum number of connections that the pool should try to maintain in the available list. When the buffer size falls below the buffer minimum, the pool maintenance thread will be notified to create new connections. When notified, the thread will immediately attempt to create the number of connections to fill the difference. New connections will not be created if the pool is already at its maximum size. When creating new connections the thread uses the attributes of the most recent client request that resulted in a new connection being created.
Setting this parameter to "0" will disable maintenance of the buffer minimum.
However, the buffer maximum will still be maintained.
Setting this parameter to a number greater than the maximum pool size(FND_MAX_JDBC_CONNECTIONS) will disable all buffer maintenance.
FND_JDBC_BUFFER_MAX
======================
The buffer maximum is the maximum number of connections that the pool should try to maintain in the available list. During heavy usage, the buffer may exceed this maximum. However, during periods of low usage, the maintenance thread will decrease the buffer size until the buffer maximum is reached.
If the value of this parameter is an integer, (for example "20") the buffer maximum is static. If the value is a percent (for example, "20%"), the buffer maximum is not constant but instead is calculated dynamically as a percent of total pool size. The buffer minimum is also taken into account when
determining a dynamic buffer maximum.
The exact expression used is:
maximum(t) = buffer minimum + ( (FND_JDBC_BUFFER_MAX/100) * size(t) )
where maximum(t) and size(t) are the buffer maximum and pool size at some time t.
The thread is configured to periodically check the buffer size. If the buffer size is greater than the maximum, the thread will remove either the number of available connections specified by FND_JDBC_BUFFER_DECAY_SIZE or the number of connections in excess of the buffer minimum, whichever is smaller. When connections are removed from the available list, the least recently used ones are removed first.
Setting this parameter to100%, or to a number equal to FND_MAXIMUM_JDBC_CONNECTIONS, or to a number less than or equal to FND_JDBC_BUFFER_MIN will effectively prevent the maintenance thread from ever removing any connections.
FND_JDBC_BUFFER_DECAY_INTERVAL
===================================
The buffer decay interval specifies how often the connection pool maintenance thread should check the buffer size. The thread will check the buffer size at most once every FND_JDBC_BUFFER_DECAY_INTERVAL seconds. The actual time between consecutive thread cycles will vary somewhat depending on the JVM load.
This parameter, along with FND_JDBC_BUFFER_DECAY_SIZE, allows the buffer decay rate to be tuned. For example, if the buffer decay size is 2 and the buffer decay interval is one minute, the buffer decay rate will never exceed two connections per minute. When connections are removed, the least recently used ones are removed first.
FND_JDBC_BUFFER_DECAY_SIZE
=============================
The buffer decay size specifies the maximum number of connections that should be removed during any single thread cycle during which the number of available connections is greater than the buffer size. This parameter, along with FND_JDBC_BUFFER_DECAY_INTERVAL, allows the buffer decay rate to be tuned.
FND_JDBC_MAX_WAIT_TIME
=========================
The maximum wait time specifies how much time a client should spend trying to get a connection. The borrow algorithm, used to borrow an object from the pool, contains check points at which the elapsed time is compared to the maximum wait time. If it exceeds the maximum wait time, then a null object will be returned to the client. The pre-configured value for the maximum wait time is
10 seconds.
FND_JDBC_SELECTION_POLICY
============================
The selection policy determines how a connection is selected from the list of available connections for a particular client. The connection pool is pre-configured to use a cost-based selection algorithm, which selects the connection that will require the smallest amount of initialization to match the
client's context.
FND_JDBC_USABLE_CHECK
===========================
The FND_JDBC_USABLE_CHECK parameter governs whether a pl/sql query is performed before giving a connection to a client. The pool checks whether a connection is usable before handing it to a client. This always involves checking that the connection is not null and is not closed. If FND_JDBC_USABLE_CHECK is set to true, then it also verifies that the connection can be used to perform a simple PL/SQL query. (This parameter may have to be set to "true" in order to clean up
connections to a database that has been restarted.)
FND_JDBC_CONTEXT_CHECK
==========================
The FND_JDBC_CONTEXT_CHECK parameter governs whether the AOL security context and NLS state is obtained from the database when the connection is returned to the pool. If FND_JDBC_CONTEXT_CHECK is "true", when the connection is returned to the pool, the AOL security context and NLS state will be obtained from the database. (This is implemented in the DBConnObj.isReusable() method). This check must be done when the connection is returned (rather than when it is borrowed) so that the selection matching algorithm has access to the actual
session context of the connections in the available list.
FND_JDBC_PLSQL_RESET
========================
The PL/SQL reset flag, set using the variable FND_JDBC_PLSQL_RESET, governs whether the PL/SQL state associated with a connection should be freed before the pool hands the connection to the client. By default this flag is false.
If the flag is set by true, by including the line "FND_JDBC_PLSQL_RESET=true" in the .dbc file, each connection to the database will have its PL/SQL state cleared before the pool returns the connection to the client.
This is how it works. After the pool selects a connection from the available list for a client, it initializes the connection. One of the things initialization does is to set a flag that is later used by SessionManager to determine if the apps initialization routine needs to be performed for the connection. When FND_JDBC_PLSQL_RESET has been set to "true", this flag will always be set to true. After the pool initializes the connection, it also checks whether the connection is usable. In this case, this check will include a call to DBMS_SESSION.RESET_PACKAGE, which frees the PL/SQL state. The table below summaries the affect of FND_JDBC_PLSQL_RESET and the other safety check parameters on borrowing a connection from the pool.
The FND_JDBC_PLSQL_RESET parameter has been added to only to address the case where production PL/SQL global bugs are known to exist. The performance of the pool is reduced by setting this flag to true.
Reference : Note 264599.1

Purpose
JVM 이 과도한 CPU / Memory를 사용하게 되어 Application Performance에 영향을 미칠때가 있으며 이럴경우 Connection Pool 관련하여 Parameter Tunning을 해야 할때가 있습니다. 이때 사용되는 Parameter들의 의미를 설명하고자 합니다.
The Applications Database Connection Pool is a pool of JDBC database connections that are shared among java applications. Applications obtain connections from the pool by using the getJDBCConnection(...) methods of AppsContext.
Essentially, each AppsContext has a single database connection associated with it at all times.
The AOL/J layer internally borrows and returns this connection to the pool as needed to maintain connection reference that is properly initialized for the current Java tier AOL security context and NLS state.
FND_MAX_JDBC_CONNECTIONS
============================
The maximum pool size is the maximum allowed sum of the number of available connections and thenumber of locked connections. If the pool reaches the maximum size and all connections are locked, new clients will not be able to borrow a connection until one of the current clients has returned one. The default setting for this parameter is essentially unlimited (about 2 billion).
FND_JDBC_BUFFER_MIN
======================
The buffer minimum is the minimum number of connections that the pool should try to maintain in the available list. When the buffer size falls below the buffer minimum, the pool maintenance thread will be notified to create new connections. When notified, the thread will immediately attempt to create the number of connections to fill the difference. New connections will not be created if the pool is already at its maximum size. When creating new connections the thread uses the attributes of the most recent client request that resulted in a new connection being created.
Setting this parameter to "0" will disable maintenance of the buffer minimum.
However, the buffer maximum will still be maintained.
Setting this parameter to a number greater than the maximum pool size(FND_MAX_JDBC_CONNECTIONS) will disable all buffer maintenance.
FND_JDBC_BUFFER_MAX
======================
The buffer maximum is the maximum number of connections that the pool should try to maintain in the available list. During heavy usage, the buffer may exceed this maximum. However, during periods of low usage, the maintenance thread will decrease the buffer size until the buffer maximum is reached.
If the value of this parameter is an integer, (for example "20") the buffer maximum is static. If the value is a percent (for example, "20%"), the buffer maximum is not constant but instead is calculated dynamically as a percent of total pool size. The buffer minimum is also taken into account when
determining a dynamic buffer maximum.
The exact expression used is:
maximum(t) = buffer minimum + ( (FND_JDBC_BUFFER_MAX/100) * size(t) )
where maximum(t) and size(t) are the buffer maximum and pool size at some time t.
The thread is configured to periodically check the buffer size. If the buffer size is greater than the maximum, the thread will remove either the number of available connections specified by FND_JDBC_BUFFER_DECAY_SIZE or the number of connections in excess of the buffer minimum, whichever is smaller. When connections are removed from the available list, the least recently used ones are removed first.
Setting this parameter to100%, or to a number equal to FND_MAXIMUM_JDBC_CONNECTIONS, or to a number less than or equal to FND_JDBC_BUFFER_MIN will effectively prevent the maintenance thread from ever removing any connections.
FND_JDBC_BUFFER_DECAY_INTERVAL
===================================
The buffer decay interval specifies how often the connection pool maintenance thread should check the buffer size. The thread will check the buffer size at most once every FND_JDBC_BUFFER_DECAY_INTERVAL seconds. The actual time between consecutive thread cycles will vary somewhat depending on the JVM load.
This parameter, along with FND_JDBC_BUFFER_DECAY_SIZE, allows the buffer decay rate to be tuned. For example, if the buffer decay size is 2 and the buffer decay interval is one minute, the buffer decay rate will never exceed two connections per minute. When connections are removed, the least recently used ones are removed first.
FND_JDBC_BUFFER_DECAY_SIZE
=============================
The buffer decay size specifies the maximum number of connections that should be removed during any single thread cycle during which the number of available connections is greater than the buffer size. This parameter, along with FND_JDBC_BUFFER_DECAY_INTERVAL, allows the buffer decay rate to be tuned.
FND_JDBC_MAX_WAIT_TIME
=========================
The maximum wait time specifies how much time a client should spend trying to get a connection. The borrow algorithm, used to borrow an object from the pool, contains check points at which the elapsed time is compared to the maximum wait time. If it exceeds the maximum wait time, then a null object will be returned to the client. The pre-configured value for the maximum wait time is
10 seconds.
FND_JDBC_SELECTION_POLICY
============================
The selection policy determines how a connection is selected from the list of available connections for a particular client. The connection pool is pre-configured to use a cost-based selection algorithm, which selects the connection that will require the smallest amount of initialization to match the
client's context.
FND_JDBC_USABLE_CHECK
===========================
The FND_JDBC_USABLE_CHECK parameter governs whether a pl/sql query is performed before giving a connection to a client. The pool checks whether a connection is usable before handing it to a client. This always involves checking that the connection is not null and is not closed. If FND_JDBC_USABLE_CHECK is set to true, then it also verifies that the connection can be used to perform a simple PL/SQL query. (This parameter may have to be set to "true" in order to clean up
connections to a database that has been restarted.)
FND_JDBC_CONTEXT_CHECK
==========================
The FND_JDBC_CONTEXT_CHECK parameter governs whether the AOL security context and NLS state is obtained from the database when the connection is returned to the pool. If FND_JDBC_CONTEXT_CHECK is "true", when the connection is returned to the pool, the AOL security context and NLS state will be obtained from the database. (This is implemented in the DBConnObj.isReusable() method). This check must be done when the connection is returned (rather than when it is borrowed) so that the selection matching algorithm has access to the actual
session context of the connections in the available list.
FND_JDBC_PLSQL_RESET
========================
The PL/SQL reset flag, set using the variable FND_JDBC_PLSQL_RESET, governs whether the PL/SQL state associated with a connection should be freed before the pool hands the connection to the client. By default this flag is false.
If the flag is set by true, by including the line "FND_JDBC_PLSQL_RESET=true" in the .dbc file, each connection to the database will have its PL/SQL state cleared before the pool returns the connection to the client.
This is how it works. After the pool selects a connection from the available list for a client, it initializes the connection. One of the things initialization does is to set a flag that is later used by SessionManager to determine if the apps initialization routine needs to be performed for the connection. When FND_JDBC_PLSQL_RESET has been set to "true", this flag will always be set to true. After the pool initializes the connection, it also checks whether the connection is usable. In this case, this check will include a call to DBMS_SESSION.RESET_PACKAGE, which frees the PL/SQL state. The table below summaries the affect of FND_JDBC_PLSQL_RESET and the other safety check parameters on borrowing a connection from the pool.
The FND_JDBC_PLSQL_RESET parameter has been added to only to address the case where production PL/SQL global bugs are known to exist. The performance of the pool is reduced by setting this flag to true.
Reference : Note 264599.1

Issues with multiple Files with multiple subdbs on a single environment.

I'm having an issue with Berkeley DB 4.2 on 32-bit platforms, regarding multiple physical files with multiple subdatabases in a single database environment. Specifically, when I open a subdatabase for a physical file, Berkeley DB thinks that it is using the same subdatabase in a different physical file.
I'm doing the following:
1. Create and open a db enviornment.
2. Move file1 to the common area.
3. Open, get and close the subdatabases in file1.
4. Move file2 to the common area.
5. Open, get and close the subdatabases in file2.
6. remove file2 from the common area
7. Move file3 to the common area.
8. Open a subdatabase from file3. About 1/2 the time, the fetches
return data from file2, not from file3.
It's possible that at some earlier time (i.e. before step 1 of this
test case), file1, file2 and file3 were the same file. I noticed
that there is something called env->fileid_reset, but that is not
in 4.2.52.
Any ideas?

Looks like I've resolved the issue

Multiple DataBase Connection in a Single Form

hi all
Is it Possible to have Multiple Database Connection With a Single Form
Block a : Retriving data from a database Service a/Schema A.
Block b : Retriving data from a Remote Database Service b / Schema B.
If yes how to do this.
regards
jai
email:[email protected]

Sure you can access a database this way,
but can you base a block on this database connect? No you can't.
Frank

Simultaneously Connecting Multiple Tables of the same Database to Textboxes of the same Form using a single ADO Control Code using VB6 Enterprise Edition and MS Access 2007

Iv 10 Tables consisting of atleast 10 fields each in a single Database. Bt, Im only able to connect 1 table at a time to a form using an ADO Control. Im able to add data from table 'student' to text-boxes in my form. Bt, hw can I add data from field(0) of
Table 'Student' to Textbox1 and data from field(0) of Table 'Marks' to Textbox2 using VB6??
This is the current sample coding iv got to connect a single table to a form:
Global con As New ADODB.Connection
Global rs As New ADODB.Recordset
Public Function Connect()
If con.State = 1 Then con.Close
con.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + App.Path + "\bca.mdb;Persist Security Info=False"
End Function
Private Sub Add_Click()
If rs.State = 1 Then rs.Close
rs.Open "select * from student", con, adOpenDynamic, adLockOptimistic
rs.AddNew
rs.Fields(0) = (Text1.Text)
rs.Fields(1) = (Text2.Text)
rs.Fields(2) = (Text13.Text)
rs.Fields(3) = (Text4.Text)
rs.Fields(4) = (Text5.Text)
rs.Fields(5) = (Text6.Text)
rs.Fields(6) = (Text7.Text)
rs.Fields(7) = (Text8.Text)
rs.Fields(8) = (Text9.Text)
rs.Fields(9) = (Text10.Text)
rs.Fields(10) = (Text11.Text)
rs.Update
MsgBox " Record Added"
End Sub
What can I do to add fields from 2 different tables to different text boxes within the same form using a single ado control using vb6 and MS Access 2007??

Hi,
Since VB6 product is not supported in this forum, you may go to these forums for support:
#Where to post your VB 6 questions
http://social.msdn.microsoft.com/Forums/en-US/6a0719fe-14af-47f7-9f51-a8ea2b9c8d6b/where-to-post-your-vb-6-questions
Thank you for your understanding.
Best regards,
Franklin
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Single Database Session Per User in ADF/BC Application

Hi, I am using ADF with BC (JDeveloper 11.1.1.1). My application contains multiple application modules, each connected to the same JDBC data source. On the app server, I have configured the data source to use Identity Based Connection Pooling.
My current configuration is resulting in numerous database sessions for each user. I have a requirement to use only a single database session per user HTTP session. Is there any way to configure the application modules to achieve this?
Thanks,
Brad

Hi,
use a single root Am module and make sure the others are used as nested modules. This will create a single connection
Frank

Multiple sessions in a single database connection.

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