How to understand the structure of MS SQL 2005 tables if there is no documentation for the application?

Question

SQL

Is CRM, uses MS SQL 2005, ~600 tables. The database stores data of ~20 directories - goods, prices, warehouses, units of measurement, etc. There is no documentation on linking directories with tables. Is there any technique or maybe software that allows you to understand the correspondence between directories and tables? And is it really possible to figure this out without documentation?

Answer 1

Tables without links?
If with links, as an option, you can first build a diagram using SQL Server Management Studio to clearly understand what's what