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I got stuck in some code. I'm working now on the return of the SQL database (note that - no SQL SERVER MANAGEMENT STUDIO) built into the MDF file VISUAL STUDIO The code looks like this:
using (SqlCommand cmd = new SqlCommand(query, MyConnection))
cmd.Notification = null;
DataTable dt = new DataTable();

SqlDependency dependency = new SqlDependency(cmd);
if (MyConnection.State == ConnectionState.Closed)

var rdr = cmd.ExecuteReader();
if (dt.Rows.Count > 0)
name = dt.Rows[0]["ProdName"].ToString();
price = int.Parse(dt.Rows[0]["Price"].ToString());
image = dt.Rows[0]["Images"].ToString();


dependency.OnChange += new OnChangeEventHandler


But for some reason it does not work and appears to me an error that says:
"A database with the same name exists, or specified file cannot be opened, or it is located on UNC share"

I also updated the file WEB.CONFIG

sqlCacheDependency pollTime="500" enabled="true"

add name="Dataprod" connectionStringName="ConnectionString"


And it does not work

Updated 15-May-15 3:16am

1 solution

The error, "A database with the same name exists ...", suggests that there's a problem with your connection string.

Most likely, you've specified AttachDbFileName, but forgotten to specify User Instance=true;. As a result, SQL has attached your MDF file as a regular database; when it tries to attach it a second time, the database already exists, and you get this error.

To solve the problem, manually detach the existing database, and add the missing setting to your connection string.
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Member 11516170 15-May-15 10:21am    
So what should I do
name="ConnectionString" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\Dataprod.mdf;Integrated Security=True;" providerName="System.Data.SqlClient"

Thank you in advance for your help
Richard Deeming 15-May-15 10:22am    
Start by reading my answer!
Member 11516170 15-May-15 10:26am    
Sorry, I'm not the best that toward English
Right now I'm working on it


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