Database storage and use of hierarchical data

Data in the tree structure is often seen in application systems.ArticleThere are also quite a few. The following are some of the materials I have collected in my actual work and some of my work.

Four ways to work with Hierarchical Data
Storing hierarchical data in a database
Oracle9i Database daily feature-querying hierarchical data with connect
Hierarchical Data with ADO. net
Notes on storing hierarchical data in a database
Pre-order traversal
Trees in SQL 1 2
A look at SQL trees
Display HierarchicalDataWith Treeview

How to store multi-level structured data in a database