MVC and MySql examples
The goal is to facilitate operations in hierarchical tables using functions available for hierarchyid data type.
There are two challenges:
- Simplify use through set of simple commands.
- Using Entity Framework without changes, enable hierarchy operations in other databases, in addition to SQL Server.
We will use only five basic operations to maintain the hierarchy:
- Adding a new element (as last child of a given parent).
- Promotion. To the same level of his parent.
- Demotion. Becomes the last child of the previous sibling.
- Moving up approaching the parent.
- Move down away from the parent.
Through these operations it is possible to position a record anywhere in the hierarchy.
- We will not use the hierarchyid field. In its place a varbinary field (892). This will allow the Entity Framework to map the field.
- In hierarchy services functions we can convert the byte array data to SqlHierarchyid data type.
- So the application can use the basic functions of the hierarchy handling.
- This is even possible for other databases in addition to MS SQL Server.
- Just use to the field that stores the hierarchyid data, a data type that is mapped to byte array.
- For MySql, for example, varbinary worked in this application.
Sample Projects on GitHub
- HidMy – Accessing MySql using Hierarchy.Universal namespace.
- HidMS – Accessing Sql Server using Hierarchy.SqlServer namespace.
- Both project will load nuget package EntityFramework.Hierarchy.