When nameOrConnectionString is a connection string - what providerName should be used?

Question

I am writing my own class that wraps some ADO.NET calls, one of the parameters I want to accept is a "nameOrConnectionString" similar to what lots of ORMs seem to accept

If the parameter is a name (I can determine this by the number of '=' characters in the string) then I can go to the config file and get the actual connectionString as well as the providerName - there is no issue.

But if I was passed a connectionString, how do I determine the which providerName to use, is there a parameter within the connectionString that can specify this, should it default to something reasonable like System.Data.SqlClient, or is there no real standard around this?

Some code to illustrate

    public Db(string nameOrConnectionString)
    {
        string connectionString;
        string providerName;

        string name;
        //some method that determines if the nameOrConnectionString is a name and outputs the name
        if(ParseConnectionStringName(out name)){
            //if its a name i can pull relevant details from config
            var settings = ConfigurationManager.ConnectionStrings[name];
            if (settings == null)
                throw new ArgumentException("nameOrConnectionString");
            connectionString = settings.ConnectionString;
            providerName = settings.ProviderName;
        }
        else
        {
            //nameOrConnectionString is a connectionString, but what is providerName
            connectionString = nameOrConnectionString;
            providerName = "????" //what should this be?
        }


        //I need provider name to get a DbProviderFactory
        DbProviderFactory = DbProviderFactories.GetFactory(providerName);

        //....
    }

Answer 1

C# connection strings contains Provider Name. By Default it's missing that's mean provider is System.Data.SqlClient. For other providers provide name must be provided.

Answer 2

An OLE DB connection string will always have a provider value and an ODBC connection string will always have a driver. Mind you, if you use a DSN with ODBC then the driver will be in the DSN. There's really is no way to know to know for sure in all cases though. I haven't used lots of ORMs but Entity Framework stores the provider in the config file too. I'd not be surprised if others did too.

Answer 3

You can have a look at this how to add provider name to connection string http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.sqldatasource.providername(v=vs.110).aspx

connection string has this format you can split the string to get provider name from nameOrConnectionString

<add name="SqlWinApp.Properties.Settings.ConnectionString" connectionString="Server=215-   6576;User ID=sa; Database=All-PurposeHandyman; Password=password"
  providerName="System.Data.SqlClient" />