Added Version field to SetValue()

In order to allow the `AttributeValue` to be annotated with `LastModified` metadata, we're adding `Version` to the `SetValue()` calls, based on data retrieved from the `GetTopics` stored procedure. Because the published schema for 4.0.0 doesn't return a `Version` field when calling `GetTopics`, this code checks for the number of returned columns to maintain backward compatibility; this allows this to be published as an minor version without breaking semantic versioning rules. Preferably, we'd actually check for the existence of the `value` property, but that's quite a bit more involved with `SqlDataReader`, and the column count gives us confidence in that, at least for this version. (We'll ideally want to remove this in the 5.0.0 release.)

Author: JeremyCaney

OnTopic.Data.Sql/SqlTopicRepository.cs

@@ -121,6 +121,13 @@ private static void SetIndexedAttributes(SqlDataReader reader, Dictionary<int, T
       var id                    = Int32.Parse(reader["TopicID"]?.ToString(), CultureInfo.InvariantCulture);
       var name                  = reader["AttributeKey"]?.ToString();
       var value                 = reader["AttributeValue"]?.ToString();
+      var version               = DateTime.Now;
+
+      //Check field count to avoid breaking changes with the 4.0.0 release, which didn't include a "Version" column
+      //### TODO JJC20200221: This condition can be removed and accepted as a breaking change in v5.0.
+      if (reader.FieldCount > 3) {
+        version                 = DateTime.Parse(reader["Version"]?.ToString(), CultureInfo.InvariantCulture);
+      }
 
       /*------------------------------------------------------------------------------------------------------------------------
       | Validate conditions
@@ -141,7 +148,7 @@ private static void SetIndexedAttributes(SqlDataReader reader, Dictionary<int, T
       /*------------------------------------------------------------------------------------------------------------------------
       | Set attribute value
       \-----------------------------------------------------------------------------------------------------------------------*/
-      current.Attributes.SetValue(name, value, false);
+      current.Attributes.SetValue(name, value, false, version);
 
     }
 
@@ -169,6 +176,13 @@ private static void SetExtendedAttributes(SqlDataReader reader, Dictionary<int,
       | Identify attributes
       \-----------------------------------------------------------------------------------------------------------------------*/
       var id                    = Int32.Parse(reader["TopicID"]?.ToString(), CultureInfo.InvariantCulture);
+      var version               = DateTime.Now;
+
+      //Check field count to avoid breaking changes with the 4.0.0 release, which didn't include a "Version" column
+      //### TODO JJC20200221: This condition can be removed and accepted as a breaking change in v5.0.
+      if (reader.FieldCount > 2) {
+        version                 = DateTime.Parse(reader["Version"]?.ToString(), CultureInfo.InvariantCulture);
+      }
 
       /*------------------------------------------------------------------------------------------------------------------------
       | Validate conditions
@@ -214,7 +228,7 @@ private static void SetExtendedAttributes(SqlDataReader reader, Dictionary<int,
         | Set attribute value
         \---------------------------------------------------------------------------------------------------------------------*/
         if (String.IsNullOrEmpty(value)) continue;
-        current.Attributes.SetValue(name, value, false);
+        current.Attributes.SetValue(name, value, false, version);
 
       } while (xmlReader.Name == "attribute");