SqlCacheDependency with SqlCommand not working

Question

Having problems with implementing very basic SqlCacheDependency prototype.

Have tried this with a sproc but now I'm down to straight command execution.

    public SqlCommand GetReadCommand(int ID)
    {
        SqlCommand cmd = new SqlCommand("SELECT dbo.Entity.Entity_ID, dbo.Entity.Name FROM dbo.Entity WHERE Entity_ID = @ID", _conn);
        cmd.CommandType = CommandType.Text;
        cmd.Parameters.Add(new SqlParameter("ID", ID));

        return cmd;
    }

    public SqlCacheDependency GetSqlDependency(int ID)
    {
        SqlCommand cmd = GetReadCommand(ID);
        SqlCacheDependency dep = new SqlCacheDependency(cmd);
        return dep;
    }

And I'm reading a dataset of all objects and creating a very simple dependency test on some data I inserted manually:

    public DataSet SelectAll()
    {
        DataSet result;
        if (_cache["Entity_FullSet"] == null)
        {
            SqlCommand cmd = new SqlCommand("dbo.GetAllEntities", _conn);
            cmd.CommandType = CommandType.StoredProcedure;
            _conn.Open();

            SqlDataAdapter da = new SqlDataAdapter(cmd);
            result = new DataSet();
            da.Fill(result);


            _cache[MasterCacheKey()] = DateTime.Now;
            string[] mk = new[] { MasterCacheKey() };
            CacheDependency cd = new CacheDependency(null, mk);

            SqlCacheDependency scd = new SqlCacheDependency(GetReadCommand(1));
            CacheDependency[] cds = new[] { cd, scd };

            AggregateCacheDependency acd = new AggregateCacheDependency();
            acd.Add(acd);

            _cache.Insert("Entity_FullSet", result, scd);
            _conn.Close();
        }
        else
        {
            result = (DataSet)_cache["Entity_FullSet"];
        }
        return result;
    }

The 'master key' is there for testing aggregate cache dependencies - changing it works great, but the sql dependency on 1 (variable scd) simply isn't working. If I go and update the table - even delete the row - nothing happens, the cache isn't cleared.

Any ideas as to why the sql dependency isn't registering/firing would be greatly appreciated!

Answer 1

Have you enabled service broker in the DB, and turned on query notifications?

ALTER DATABASE [YourDB] SET ENABLE_BROKER WITH ROLLBACK IMMEDIATE

In Application_Start():

SqlDependency.Start(connectionString)

And call Stop() in Application_End().

Can you post the code for your stored procedure? Do you by any chance have SET NOCOUNT ON at the beginning of your SP? If so, that will prevent query notifications.

For the code as posted above, try replacing those 3-part column names with one or two-part names. For example, replace "dbo.Entity.Entity_ID" with "Entity_ID" or (better) "e.Entity_ID" (after assigning the alias "e" to dbo.Entity).