Using closure tables to model hierarchy in T-SQL

credit https://www.slideshare.net/billkarwin/models-for-hierarchical-data

• open an SQL server database
• run createTables.sql - creates tables
• run InsertNode.sql - creates stored procedure for inserting nodes
• run DeleteNode.sql - creates stored procedure for deleting nodes
• run DeleteSubtree.sql - creates stored procedure for deleting subtrees
• run GetSubTree.sql - creates stored procedure for getting subtrees
• run TestData.sql - insert some test data
• start playing: e.g exec dbo.GetSubTree 1

The idea is that we store nodes using the Closure table approach to model hierarchy. In our case, the node would be a "ProjectItem". ProjectItems are either library items, products and containers.