Merge branch 'bugfix/SQL-migration' into develop

Previously, when running schema comparison, the auto-generated script would fail since `[dbo].[Topics]` contained values. That's because it was attempting to update the new columns from nullable to non-nullable. Any attempt to modify an existing column will throw an error during schema comparison. We create these columns during the migration script as nullable, since they don't have logical defaults, but then immediately populate them with the subsequent script. Given that, this update immediately follows that up with a query to make the columns non-nullable, thus preventing the schema comparison script from needing to modify them.

In addition, I also extended the range of possible values picked up for the `BaseTopic` migration. This was originally set to update an attribute named `InheritedTopic` to `BaseTopic`. But, due to historical reasons, that key for that attribute could also be `TopicID` or `DerivedTopic`. (Due to how OnTopic Editor 4.0.0 was written, it didn't actually matter what the key was, and thus the range of possible values.) To ensure that these works against that range, the update statement was modified to accept `TopicID`, `DerivedTopic`, OR `InheritedTopic`.

Finally, I added some additional messaging to the upgrade script to make it easier to read the output.

Author: JeremyCaney

OnTopic.Data.Sql.Database/Scripts/Upgrade from OnTopic 4 to OnTopic 5.sql

@@ -13,6 +13,8 @@
 -- migrations.
 --------------------------------------------------------------------------------------------------------------------------------
 
+PRINT('Dropping legacy columns...');
+
 ALTER
 TABLE	Topics
 DROP
@@ -38,6 +40,8 @@ TABLE	ExtendedAttributes
 DROP
 COLUMN	DateModified;
 
+PRINT('Dropped legacy columns');
+
 --------------------------------------------------------------------------------------------------------------------------------
 -- MIGRATE CORE ATTRIBUTES
 --------------------------------------------------------------------------------------------------------------------------------
@@ -46,10 +50,12 @@ COLUMN	DateModified;
 -- in a way that's inconsistent with other attributes. By moving them to Topic, we better acknowledge their unique status.
 --------------------------------------------------------------------------------------------------------------------------------
 
-ALTER TABLE [dbo].[Topics]
-    ADD [TopicKey]    VARCHAR (128) NULL,
-        [ContentType] VARCHAR (128) NULL,
-        [ParentID]    INT           NULL;
+PRINT('Migrating core attributes...');
+
+ALTER TABLE	[dbo].[Topics]
+ADD	[TopicKey]		VARCHAR(128)	NULL,
+	[ContentType]		VARCHAR(128)	NULL,
+	[ParentID]		INT	NULL;
 
 WITH KeyAttributes AS (
   SELECT	TopicID,
@@ -82,6 +88,12 @@ PIVOT (	MIN(AttributeValue)
 WHERE	RowNumber		= 1
 AND	Topics.TopicID		= Pvt.TopicID
 
+ALTER TABLE	[dbo].[Topics]
+ALTER COLUMN	TopicKey		VARCHAR(128)	NOT NULL;
+
+ALTER TABLE	[dbo].[Topics]
+ALTER COLUMN	ContentType		VARCHAR(128)	NOT NULL;
+
 DELETE
 FROM	Attributes
 WHERE	AttributeKey
@@ -90,6 +102,8 @@ IN (	'Key',
 	'ParentID'
 )
 
+PRINT('Migrated core attributes');
+
 --------------------------------------------------------------------------------------------------------------------------------
 -- MIGRATE TOPIC REFERENCES
 --------------------------------------------------------------------------------------------------------------------------------
@@ -99,6 +113,8 @@ IN (	'Key',
 -- service to infer which attributes represent relationships in order to translate their values from `TopicID` to `UniqueKey`.
 --------------------------------------------------------------------------------------------------------------------------------
 
+PRINT('Migrating topic references...');
+
 CREATE
 TABLE	[dbo].[TopicReferences] (
 	  [Source_TopicID]	INT	NOT NULL,
@@ -118,6 +134,8 @@ WHERE	AttributeKey		LIKE '%ID'
   AND	ISNUMERIC(AttributeValue)	= 1
   AND	Topics.TopicID		IS NOT NULL
 
+PRINT('Migrated core attributes');
+
 --------------------------------------------------------------------------------------------------------------------------------
 -- MIGRATE DERIVED TOPICS
 --------------------------------------------------------------------------------------------------------------------------------
@@ -127,15 +145,19 @@ WHERE	AttributeKey		LIKE '%ID'
 -- and how its 'ReferenceKey'.
 --------------------------------------------------------------------------------------------------------------------------------
 
+PRINT('Migrating base topics...');
+
 UPDATE	TopicReferences
 SET	ReferenceKey		= 'BaseTopic'
 WHERE	ReferenceKey		= 'Topic'
 
 UPDATE	Topics
 SET	TopicKey		= 'BaseTopic'
-WHERE	TopicKey		= 'InheritedTopic'
+WHERE	TopicKey		IN ('TopicID', 'InheritedTopic', 'DerivedTopic')
 AND	ContentType		= 'TopicReferenceAttribute'
 
+PRINT('Migrated base topics');
+
 --------------------------------------------------------------------------------------------------------------------------------
 -- MIGRATE ATTRIBUTE KEYS
 --------------------------------------------------------------------------------------------------------------------------------
@@ -144,11 +166,15 @@ AND	ContentType		= 'TopicReferenceAttribute'
 -- conflict with .NET's own "*Attribute" convention (which is usually reserved for actual attributes).
 --------------------------------------------------------------------------------------------------------------------------------
 
+PRINT('Migrating attribute descriptors...');
+
 UPDATE	Topics
 SET	TopicKey		= TopicKey + 'Descriptor'
 WHERE	TopicKey		LIKE '%Attribute'
 AND	ContentType		= 'ContentTypeDescriptor'
 
 UPDATE	Topics
 SET	ContentType		= ContentType + 'Descriptor'
-WHERE	ContentType		LIKE '%Attribute'
+WHERE	ContentType		LIKE '%Attribute'
+
+PRINT('Migrated attribute descriptors');