v4.3.0

This update provides backend functionality and bug fixes to improve performance and reliability, with a particular emphasis on importing and saving large topic graphs. The OnTopic library can now connect to empty databases, and persist in-memory topic graphs to them. To do this, it dynamically identifies content type and attribute descriptors from that topic graph. Further, when recursively saving topic graphs, there are significant performance improvements—while simultaneously fixing bugs that can occur when there are mismatches between the configuration of the saved and in-memory schemas.

Functionality

• ContentTypeDescriptors (a9ea634) and AttributeDescriptors (b0c5a5e) are now updated dynamically when saved, and thus configuration changes are now available immediately without requiring an application restart (fb3366e).
• The byline (LastModifiedBy) and dateline (LastModified) are now only persisted to the underlying topic repository if any other attributes (d8d41b7) or relationships (8caa148) have changed (d8d41b7).
• Arbitrary attributes (i.e., attributes not defined in the ContentTypeDescriptor) can now be programmatically added (c3c01ef), modified, or deleted (2151a08) via the OnTopic Library (8b7dffe).
• Empty databases can now be connected to without throwing exceptions, thus allowing a reference schema can be Import()ed via the OnTopic Data Transfer library using the OnTopic Editor (695664d).
• TopicRepository.Save() will now loop back and save any topics with previously unresolved (i.e., unsaved) references (including relationships or DerivedTopic) (913b68d).
• UpdateRelationships now synchronizes relationships, instead of just inserting them. It accepts an optional @DeleteUnmatched argument which can be disabled to append new relationships, instead of also deleting unmatched relationships (cbba817).

Bug Fixes

• Fixed a bug where topics from the previous relationship were saved to each subsequent relationship for a topic (27d9bfe).
• Fixed a bug where attributes that had been reconfigured away from IsIndexedAttribute, but not otherwise changed, would be orphaned (7a61005) deleted (d64d242) on Save().
• Fixed a bug where an off-target exception would be thrown if SqlTopicRepository.Load(string topicKey) wasn't able to identify a matching topic (c97dcb3).
• Fixed a bug where unsaved relationships (6da3fa4) and derived topics (a3b6da1) were saving -1 to the database if they referenced unsaved topics.

Code Changes

Performance

• Reduced execution time of UpdateTopic by 50% through optimization of queries (fae0e8d).
• SqlTopicRepository.Save() will only save topics which have actually changed; this greatly increases the performance of recursive saves when merging large topic graphs (afa1e9b).

API Changes

• Introduced AttributeValuesDataTable (313fe71) and TopicListDataTable (7a37dc9) to encapsulate the corresponding user-defined, table-valued types in SQL, and extended SqlCommand.AddParameter() to support them (0cd2506).
• Introduced TopicNotFoundException (2300e69), which derives from TopicRepositoryException and is used in ITopicRepository.Load().
• Introduced TopicRepositoryBase.GetContentTypeDescriptor() convenience method (408d01a) for loading a ContentTypeDescriptor—either from the database, or from the local topic graph.
• Introduced TopicRepositoryBase.GetAttributes() method for retrieving extended or indexed attributes, optionally filtered by IsDirty (120c55e).
• Introduced Topic.GetTopicByUniqueKey() (867b110) and Topic.GetRootTopic() (0bddfb0) extension methods to OnTopic.Queryable namespace (d18984d).
• Introduced Topic.IsNew property for tracking whether a topic is new, or if it has been persisted to the database (1678523, f046179).
• Introduced a NamedTopicCollection.IsDirty property (4762694), RelatedTopicCollection.IsDirty() (2adef58), and AttributeValueCollection.IsDirty() (d3b49ff) for tracking if any relationships or attributes have changed (afa1e9b).
• Removed legacy SqlTopicRepository.CreateRelationshipsXml() private helper function, as that functionality is no longer used (7bea7d3).

General

• Migrated to C# 8.0's new block-level using statement, in favor of placing explicit Dispose() calls in finally blocks (f85aab2)
• Migrated to GitVersion's ContinuousDeployment mode for all branches except master to simplify version incrementing on feature branches (b4105f3).

Maintenance

• Various dependency updates (20374cd, dcf4eaf) and code cleanup (718aea5) tasks.