Multiple connections on a single .mdf database (ASP.net) SQL Server - asp.net

I'm trying to place a .mdf database on a Computer A and access it simultaneously on Computer B but I'm having an error that says I cannot access the mdf file because it's being used by another process.
The setup is, the database is hosted on a Public folder in Computer A. I have Visual Studio running on both computers, and Computer B accesses the database on Computer A.
Computer A Connection path string:
C:\Users\Public\database.mdf
Computer B Connection path string:
\192.168.254.8\Public\database.mdf
Is there some sort of setting that I do not know of to enable multiple access on a db? Or this is not possible?
EDIT:
Let me rephrase my question, sorry.
There are two computers connected via a network, and I want to access one Visual Studio solution/project website. I wanted to do this as a demonstration, is it possible?

You should have an instance of SQL Server (even express) running on the host machine.
All requests from the clients should use the standard mechanisms for connecting to that server instance. In other words, they won't run their own copy of SQL Server, instead they will connect to the instance running on the host machine.

Simultaneous or direct access to Database files under any DBMS control either a very bad practice or simply impossible.
Use proper DBMS tools to access the data.
And yes - its possible to access Web site project for demo.

Install SQL Server on the host machine (the one that you want to keep your database on).
Then in Visual Studio, use the "Server Explorer" to locate the remote instance of the database. From there, you can utilize the remote instance of SQL Server in your connection string, thus allowing you to connect multiple computers to a single database.
Using two instances of SQL Server to connect to the single .mdf file is a very bad practice.

Instead of specifying the MDF file in your connection string (which, I believe, uses a form of User Instancing), you should use SQL Server Management Studio (SSMS) to attach the MDF. Then connect to SQL Server, rather than to the MDF.
You may need to move the MDF and LDF files to a place where the SQL Server identity can access them, rather than keeping them in your VS project.
Most projects keep scripts to create the DB in their VS project, but not the binary MDF itself.
When you deploy, the process is similar: use SSMS to attach the MDF on your server.

Yes, If 2 or More Computers are connected by networks like LAN You can access the Database Database1.mdf (say) from another SQL Server by entering its user name / Password /by Visual studio connection.
Disadvantages:
If more than 7~8 systems are accessing same Database same time System response slows down and Hangs up or may result error like connection pool exceeded or Device not responding..
In Big Companies they use Huge Multi-core & Multi-Processer based sever which will respond faster.
Overcome: while writing Applications Use Connection Open and Close Particularly while executing the SQL queries in other time it should be closed.
Best Programer uses Transaction instead of using normal methods. Transaction Makes Every User Access Database With valid and successful Execution of queries. These Queries (Transaction Queries) mainly executes on client machine and later updates the same over Main server when it got Time slot for it(synchronize).

Related

How to "host" SQL Server when deploying an ASP.Net site on the web

I'm about to deploy an ASP.NET web application for testing in production. Essentially, this is just a table that is linked to a SQL Server table/view that is obviously dynamic when the data in the tables are updated.
I have a hosting plan with a site that I'll be pushing the files to, which includes a SQL Server database in the hosting plan. I also host a SQL Server instance on the network.
My question is, what is the standard way of dealing with SQL Server in this deployment? I think I have the options below, but as someone who has only ever developed applications offline, this is new to me, so please excuse my novice ignorance.
Have the application connect via IP address in the connection string to my SQL Server instance, as specifying the server name (SQLDEVSRV01 for example) won't be on the "network" when it's sitting in the site's FTP. Am I to assume my connection string will only work on the network, and once deployed to a website, will cease to function unless connecting via TCP/IP?
Host the server on the web in the same site host location. So upload the site files to my website host and setup the SQL server there. Would I be able to just specify the Server name (SQLDEVSRV01 for example) in the connection string there, as whilst it wouldn't work in development as it wouldn't be on the same network, it would then work once deployed on the web?
Embed a SQL Server instance within the app using localdB or something similar to hold the background data. If this is the case, can the data be accessed from the backend, either using SSMS or some other method?
Essentially, my aim here is to have the web app retrieve the data live from a view/table hosted in SQL server, where the backend data can be amended, manipulated and updated independently of the app, so the app can just pull the data when refreshed.
The standard way of doing this is to deploy your database to the hosting providers SQL Server instance and then connect your app to it using a connection string with their details. As it is normally a shared instance you do not have to normally worry about having the SQL instance machine patched etc.
Personally I would not be installing SQL Server myself unless I decided there was benefit to having an instance I wanted the control over nor would I be changing the structure or implementation of my application to suit a hosting providers setup.

Dynamic stored procedure in different SQL servers?

My client wants to change servers from the application, I mean enter new SQL servers name from application and search keywords in the SQL server database tables. I have Stored Producer which is working fine for one SQL server.
If client changes SQL server name in the application level then My connection string in the application will not work. Because database in the connection string that I used is available for one server.
How can I handle this situation? . Is there anyway sp that will be dynamic? P
Well in one server you could create a synonym that points at the other server. Assuming you have linked servers, on Server1:
CREATE SYNONYM dbo.ProcedureName FOR Server2_Linked.DatabaseName.dbo.ProcedureName;
Now when the app calls dbo.ProcedureName in Server1, unbeknownst to it, it is actually executing on Server2.
If this isn't what you're after I think you'll have to elaborate in your question a bit.

Dynamically switching receive locations between database servers

Using BizTalk I need to read data from one of two databases that are hosted in Unix using ODBC.
The data is replicated between the databases and if one of the databases does not respond I need to switch to the other. There is no load balancer or anything so I need to be able to do the switch on the BizTalk server.
I was thinking of creating two receive locations, one for each database server, only one of them enabled and then have a Windows service that periodically tries to make a connection to one of the database servers and if there is an exception, call a powershell script that disables the receive location for the server that does not respond and enable the other receivelocation.
Is there a better solution for this?
I would solve this as follows:
In Biztalk create a single http receive location.
Create a windows service
In the windows service poll the first database, if it does not respond poll from the second database
Have the Biztalk service post the information to the http receive location
You need to consider what happens if you read the same data twice, once from the main database and once from the backup.

Sending files from server to client with ASP.NET

I am developing a C# ASP.NET 4.0 application that will reside on a Windows Server 2003. By mean of accessing this application through a network computer, any user would be able to upload files to the windows server. But also, once these files are stored on server, he/she would be able to copy these files from the windows server to another networked computer.
I have found a way to upload files to a specified location on the server disk,
but now I need to send these files that are on server disk to the client computers.
My question is: Is there any way to send or copy files from server to other client computers (not the one that is accessing the web service) without needing a program recieving those files on the client computers? FTP, WCF, cmd commands, sockets?
Any idea?
If you want users of your webapp to download files, I'd look into an "ashx generic handler." It will allow you to send files back down to clients over HTTP(s).
If you are looking to have remote users, tell your webserver to copy files to other servers ON THE SAME LAN AS THE SERVER, you would write using normal System.IO operations.
Over a LAN, if you have the correct permissions and so on, you can write to a disk on a different machine using File.Copy -- there's nothing special about that.
If we're talking about remote machines over the internet, that's a different story. Something has to be listening whether it's FTP, WCF, DropBox, etc.
If the problem is that it can be painful to get something like WCF to work from a client due to problems like firewall issues under Windows 7, you could take a different route and have the client periodically ping the server looking for new content. To give the server a point of reference, the ping could contain the name or creation date of the most recent file received. The server could reply with a list of new files, and then the client could make several WCF calls, one by one, to pull the content down. This pattern keeps all the client traffic outbound.
You can if you can run the program as an account that has access to that computer. However having this sort of access on your network that would grant access to the outside world to put an unfiltered file on your internal network is just asking to be hacked.
Finally, I decided to install a FileZilla FTP server on each client computer and my page is working very well. But another option is to create a work group in the windows server and put every client computer to work in this work group, so that Windows server have access to the computers in the same work group.
Here are some links that may help to create the work groups:
http://helpdeskgeek.com/networking/cannot-see-other-computers-on-network-in-my-network-places/
http://www.computing.net/answers/windows-2003/server-2003-workgroup-setup-/1004.html

How to replicate or synchronize when databases can't have a direct connection with each other?

I have a central webservice over the internet which gets different information from different softwares and stores them in a Sql server 2008R2 database.
In addition to webservice some windows applications exist in different cities which all of them have local databses.
Now I wanna have replication between these local databases and the central database. but there is no any direct connection as like as "VPN" between local databases and central database.
so how can I do something like replication or synchronization between local databases and central database over the internet.
I'm thinking about sending local databases via web service. what is your idea?
My local databases are Sql server 2000 version
How about log shipping? You can even use FTP (FTPS--FTP over SSL, for security) to send the logs to be later on applied to the central DB. Since you have SQL 2000, you'd have to restore data to a copy of the DB in "restore" mode and then merge with central DB using SQL.
Also, from personal experience--if setting VPN is costly, you can consider using SSH. Free implementations for Windows exist, and they do a good job for secure file copy, just like FTPS.
I wouldn't use a webservice for this purpose, especially if the amount of data is large.

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