2 Connection Strings - Entity Framework- select at runtime

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I have an application that connects to a MYSQL database. I use Entity Framework to do all the job.
Now When I first Installed, I set up entity, and resulted in a connection string like this:

C#

<connectionStrings>
    <add name="networkingEntities" connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=MySql.Data.MySqlClient;provider connection string="server=localhost;user id=root;password=lucian;persist security info=True;database=networking"" providerName="System.Data.EntityClient"/>
  </connectionStrings>

Now, my application has 2 users: an admin and a student.

Form1 => updates information from database and from server

Login form=> the users authentificate

MainForm => where all the action takes part. If the admin is logged in he can modify contents in the database

The database:
has 2 users: root and lucian.

"lucian" is a limited user...

Now, my problem is:

How can I add a second connection string to the already existing one, and select that one at runtime? I mean, when Form1 is running, put the thread to sleep, select the second connections string and then, go to Login form, login as admin and make the cnahge sin the database?

And how can I get tho login information from the connection string, from an external file?

Posted 14-May-13 8:22am

Luci C

Updated 14-May-13 8:23am

v2

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Comments

Roman Zinnatov 14-May-13 15:23pm

Please, let me ask you some questions.
First of all. Two connection strings will be differ by login credentials. One for each user? Am I right?

Luci C 14-May-13 15:25pm

that's right...

Luci C 14-May-13 15:24pm

yes, that's right...

Roman Zinnatov 14-May-13 15:35pm

What if required to add another user? May be you should implement Membership in you app. It provides user's groups. So you will be able differentiate user's rights at application level.

Luci C 14-May-13 15:38pm

for all users I will use the first login details
for admin I will use the second login details.

Depending on which login details I use, I can do operations on the database (I have 2 separate users in the database, one limited and root)

Roman Zinnatov 14-May-13 16:02pm

I suggest to you differentiate user's rights at application level. It is usual approach and there are a lot of articles over the Internet about it.
So, if it is not for you: may be you should have two connection strings in config file and in proper moment choose one, perform connection to db and do your magic =)

2 solutions

Solution 1

To change connection of Entity Framework dynamically, you will have to pass connection string to the constructor of DataContext class as below.

C#

string connection = "YourConnectionString";
DataContext myDataContext = new DataContext(connection);

Quote:
And how can I get tho login information from the connection string, from an external file?

You may use configuration file like web.config/app.config to maintain your connection string and access it as shown in below link.

http://social.msdn.microsoft.com/Forums/en-US/linqtosql/thread/45527f5e-a380-490f-84d5-88c31cb9a03a/

Posted 14-May-13 9:14am

RaisKazi

Comments

Luci C 14-May-13 15:18pm

but I don't use a dataContext class... It's all done by entity framework...

RaisKazi 14-May-13 15:23pm

You should first learn how Entity Framework creates connecion. Have a look at below link.
Click Here

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Luci C · Accepted Answer · 2013-05-14T10:53:00

So this is how I have solved:
1. Modified the App.config like:

C#

<connectionstrings configsource="DatabaseConnectionDetails.config" />

and this is DatabaseConnectionDetails.config:

C#

<connectionstrings>
  <add name="networkingEntities" connectionstring="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=MySql.Data.MySqlClient;provider connection string="server=localhost;user id=lucian;password=lucian;persist security info=True;database=networking"" providername="System.Data.EntityClient" />
  <add name="networkingEntitiesAdmin" connectionstring="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=MySql.Data.MySqlClient;provider connection string="server=localhost;user id=root;password=lucian;persist security info=True;database=networking"" providername="System.Data.EntityClient" />
</connectionstrings>

2.Added a contructor with string parameter to Model1.Context.tt template:

C#

  public <#=code.Escape(container)#>(string myString)
        : base(myString)
    {
<#>
if (!loader.IsLazyLoadingEnabled(container))
{
#>
        this.Configuration.LazyLoadingEnabled = false;
<#>
}
#>
    }

3. get the connection string like this:

C#

string  str = ConfigurationManager.ConnectionStrings["networkingEntitiesAdmin"].ConnectionString;

4. And whenever I want to use the context , I use(for example):

C#

 networkingEntities net=new networkingEntities(str);


public List<utilizator> ListaUtilizatori()
        {
            
            var query = from u in net.utilizator
                        select u;
            List<utilizator> users = new List<utilizator>();
            try
            {
                users = query.ToList();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
            return users;
        }

Now, I still have to discover how I encrypt the config files....
Thank you all for help...