Dual table: Auto detect the dual table name on model load. Use that table for any queries.

Also allow a custom override name to be set

src/EFCore.Jet.Data/JetConfiguration.cs

@@ -57,18 +57,13 @@ namespace EntityFrameworkCore.Jet.Data
         /// <summary>
         /// The DUAL table or query
         /// </summary>
-        public static string DUAL { get; set; } = DUALForAccdb;
+        public static string CustomDualTableName = "";
-
+        //MSysRelationships
-        /// <summary>
+        //MSysAccessStorage
-        /// The dual table for accdb
+        //#Dual
-        /// </summary>
+        //(SELECT COUNT(*) FROM MSysAccessStorage)
-        public const string DUALForMdb = "(SELECT COUNT(*) FROM MSysRelationships)";
-
-        /// <summary>
-        /// The dual table for accdb
-        /// </summary>
-        public const string DUALForAccdb = "(SELECT COUNT(*) FROM MSysAccessStorage)";
 
+        public static string DetectedDualTableName = "#Dual";
         /// <summary>
         /// Gets or sets a value indicating whether show SQL statements.
         /// </summary>

src/EFCore.Jet/Query/Sql/Internal/JetQuerySqlGenerator.cs

@@ -224,7 +224,7 @@ namespace EntityFrameworkCore.Jet.Query.Sql.Internal
         protected override void GeneratePseudoFromClause()
         {
             Sql.AppendLine()
-                .Append("FROM " + JetConfiguration.DUAL);
+                .Append("FROM " + "(SELECT COUNT(*) FROM `" + (string.IsNullOrEmpty(JetConfiguration.CustomDualTableName) ? JetConfiguration.DetectedDualTableName : JetConfiguration.CustomDualTableName) + "`)");
         }
 
         private void GenerateList<T>(

src/EFCore.Jet/Scaffolding/Internal/JetDatabaseModelFactory.cs

@@ -105,7 +105,21 @@ namespace EntityFrameworkCore.Jet.Scaffolding.Internal
                     table.Database = databaseModel;
                     databaseModel.Tables.Add(table);
                 }
-                
+
+                var tableNames = databaseModel.Tables.Select(t => t.Name).ToList();
+                if (tableNames.Contains("MSysAccessStorage"))
+                {
+                    JetConfiguration.DetectedDualTableName = "MSysAccessStorage";
+                }
+                else if (tableNames.Contains("MSysRelationships"))
+                {
+                    JetConfiguration.DetectedDualTableName = "MSysRelationships";
+                }
+                else if (tableNames.Contains("#Dual"))
+                {
+                    JetConfiguration.DetectedDualTableName = "#Dual";
+                }
+
                 return databaseModel;
             }
             finally