How can I build an excellent database structure for this classification? Thanks for pointing

白菜侠

D3 Construction Project Management
D3.1 Construction project planning management
D3.1.1 Construction project planning license
D3.1.2 Architectural planning and design
D3.1.3 Architectural planning changes
D3.2 Road and traffic engineering planning management
D3.2.1 Construction project planning license
D3.2.2 Road and traffic engineering planning and design
D3.2.3 Changes in road and traffic engineering planning
D3.3 Planning and management of urban sculptures and monuments
D3.3.1 Construction project planning license
D3.3.2 Urban sculpture and monument planning and design
D3.3.3 Change of city sculpture and monument planning

maggic

Tree-like

id parentId text

Get it

白菜侠

What do you mean by using a tree in VB?

四不像君

Just use a watch,
A field indicates the superior department! The top department is empty.
However, if you do this, the query will be slower, so you can only use multiple tables to maintain the relationship!