Hi I am working on ASP.NET MVC project. Currently I am using Model first approach, where i used to add database manually by using ADO.NET model. Currently I have 4 database and I have 4 connection strings in web.config file.
It was fine till now, since I was working on development environment. But now I need to move my code to live and problem is, in live we have like 40 to 50 databases.
So what I should do is, generate connection string dynamically when user wants to connect to particular database.
I have stored procedure for this which returns connection string and database name.
For example if I have 4 database name like db1, db2, db3 and db4, I need to compare this database name with my stored procedure results database name and if both are equal, then generate connection string equal to that database name.
And also I need to put this in session once i generate connection string, so no need to generate connection string again for particular session.
Can someone help me in this??
EF DbContext as a constructor parameter takes a name of a connection string or connection string itself. So there is no problem in generating any kind of connection string and supply this when creating DdContext.
In our application we have many tenants and have a database per tenant. For every request we lookup what tenant it is and from Settings DB provide a connection string to tenant's own database.
I've not worked with Ado.Net, but from what I see in Google, this is very similar (or based on) to Entity Framework. So down to your particular implementation, there must be a way to provide connection string to database context outwith web.config.
Related
I have a ASP.NET Web application. The application connects three different databases. So I have defined three connection string in web.config with different database name and credentials.From the application code I am pointing to the relevant connection string and firing stored procedures. Sometimes the procedures are hitting the wrong database. My guess is that as .NET cache the web.config, somehow the framework is returning the wrong connection string from cache and the application hitting the wrong database. I have checked the application code and found it is pointing to the correct connection database in all cases. Is this happening due to web.config chancing? I cannot identify the root cause of the problem. Please help.
If you are using EF to connect to the database, you have to close the scope of the context and then initialize a new context with the required connection string and then use that context to execute the SP.
I don't think this is an issue with the caching !
If there is only one DAL which connecting to different databases then it is a high chance of application mistake somewhere.
Possible solution, as we have no idea of how is you data access code looks like, is to create 3 different DAL and in each of them realize logic to work only with specified connection string.
For example create 3 different classes inherited from DbContext with different connection strings in constructors.
We use this connection string today:
Provider=SQLOLEDB; Data Source=mydomain.com; Initial Catalog=myDB;User
Id=xxx; Password=xxx;
And I like to know who is save the mydomain.com in is cache, the browser of the user or the server that run the application?
Thanks
If this is ASP.NET code, then the database connection happens on the server. The user's browser has no knowledge of your database.
I have a screen where a user selects database source from a drop down. Once that's selected I would like the information passed onto other screens so the user does not keep having to select.
How can I pass information such as this from one screen to another? Note that the information is just very small things like:
DatasourceID - 2 characters
SubjectID - 2 characters
As I am running on Azure can I assume the best place to store this would be on the client side? I saw one implementation that stored data like this:
Session["abc"] = "def";
if (Session["abc"] != null)
etc ...
Is this the best way or am I missing something. Also how would the above work when the page could be served by different servers each time around? Does the above store information locally?
The Session is stored on the Server Side. Now in Azure you have a few options where exactly it is stored. It depends on what you would like to do with this datasource. If this is something you just need in the following screen, you can store it in TempData which is stored in the session. It is kept there until you read it.
Now you have these options to store the session state:
in Azure AppFabric Cache
in a SQL Azure DB
in blob storage
Azure AppFabric Caching has got a Session provider which is very easy to set up. You can just create a new cache in the Azure portal and get the required web.config entries by clicking the according button on the toolbar. this is also explained in detail here.
Using that you can store things in the Session out of process. The downside is that it's a bit expensive (about 45$/month for a 128 MB cache). So the alternative would be to store session state in SQL Azure. There's a Session provider for SQL Azure.
Here's a link to a great introduction by Scott Hanselman to the ASP.NET universal providers. If you're not using membership, then you just need to setup System.Web.Providers.DefaultSessionStateProvider.
Just make sure you point the connection string to your SQL Azure DB. Note: You must set MultipleActiveResultSets=True in the connection string, so be sure to add it back if you’ve copied the SQL Azure connection string from the portal.
Then there is also a session provider for blog storage in the training Kit, available with a sample app at http://code.msdn.microsoft.com/windowsazure/Windows-Azure-ASPNET-03d5dc14.
I believe it is unsupported by MS.
Hope this helps.
There is a delphi application in which I am trying to connect to Oracle database Using provider MSDAORA.1 but problem is coming in connecting. Oracle error message which is coming is "Oracle error occurred, but error message could not be retrieved from Oracle"
I am able to connect to database with Oracle10g client.
Connection String: Provider=MSDAORA.1;
User ID=murat;
Password = murat;
Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp) (HOST= INGPSP)(PORT=1521))(CONNECT_DATA=(SID=INGPSP)));
Persist Security Info=False;
Please provide your expert opinion what can be the reason of this?
The service name seems to be lacking in your address.
Set a tnsnames.ora file, and use the entry as data source instead of the data_source parameter you set. Follow the steps available on the faq.
Or use use connection strings like '//host[:port]/[service_name]' for your data source: //INGPSP:1521/ServiceName
For Oracle, both Microsoft and Oracle OleDB providers are known to have issue with BLOBs. If you can, use another mean of connection.
What I see that is strange is that your HOST and SID are the same. The HOST is the name of the machine on your network and the SID is the database instance on that machine. I created the following ConnectionString for the PRD3 database on machine DB19 (there are multiple databases on DB19) on our network. I was able to connect to the database successfully with real User ID and Password.
Provider=MSDAORA.1;
Password=123456;
User ID=abc;
Data Source="(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=db19)(PORT=1521))(CONNECT_DATA=(SID=prd3)))";
Persist Security Info=True
Normally the Data Source I use is the database name as defined in TNSNAMES.ORA. It is a lot less to type (fewer potential errors) and can be changed to another database without recompiling the program (such as switching between a development database and production database).
I have an asp.net mvc application, which uses the default user database. It all works pretty well, but I would like to create some tests for it. I Have a test project, I immediately stumble upon an exception
The specified named connection is either not found in the configuration, not intended to be used with the EntityClient provider, or not valid.
But the connection string is working perfectly (at least in the mvc project's web.config). The exception is thrown by my Entity DB access logic constructor
public ASPNETDBEntities() :
base("name=ASPNETDBEntities", "ASPNETDBEntities")
{
this.OnContextCreated();
}
Any ideas?
Thanks in advance.
The problem is that when running the unit tests, you need to have a connection string set in the App.config file of the test project in order for Entity Framework to find it.
However, if you're doing unit testing you most likely don't want to access the db at all, but rather mock up some dummy objects to test against. (If this is hard to do in your code as it is, you might need some refactoring of your code...)
A third possible scenario is that you're doing integration testing, and thus want to access a real db when testing - however, it doesn't have to be the real db. It can be any db with the same database schema. I'd recommend setting up a dummy db with some dummy records in it, which you can perform tests against (and which you put a connectionstring for in the App.config file in the test project) that will not grow and become slower when the "real" db does.