3 Common Inheritance Storage Schemas

Table per hierarchy	Table per subclass	Table per concrete type
- One table contains all types within the hierarchy. - One type discriminate between types.	- One table contains the base properties across the type hierarchy. - Separate table for additional properties for each sub-type.	- Table per concrete type class including inherited properties

Database diagram support objects cannot be installed because this database does not have a valid owner

TITLE: Microsoft SQL Server Management Studio
------------------------------
Database diagram support objects cannot be installed because this database does not have a valid owner.  To continue, first use the Files page of the Database Properties dialog box or the ALTER AUTHORIZATION statement to set the database owner to a valid login, then add the database diagram support objects.

This error happened after an upgrade, the owner was already set as sa, so the solution was to change ownership into another login, then return it to sa.

Look-up tables design

1- No to a single look-up table:
   a - Scalability.
   b - Data Maintainability (Error prone)

2- Integrity on deletion:
   a - Deletion stored procedure with the logic to restrict deletion for consumed records.
   (The reason that foreign keys are not enough since typically they reside within a single DB; however, references are usually consumed from other DBs.) [My recommendation]
   b- Don't delete: Just mark as deleted or add a status per record to be defined by the business.