How do I enforce data integrity rules in my database?

Question

I\'m designing this collection of classes and abstract (MustInherit) classes…

Answer 1

Have a unique table for each type of node.

Why not just make the class you're building enforce the data integrity for its own type?

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EDIT

In that case, you can either a) use logical constraints (see below) or b) stored procedures to do inserts/edits (a good idea regardless) or c) again, just make the class enforce data integrity.

A mixture of C & B would be the course of events I take. I would have unique stored procedures for add/edits for each node type (i.e. Insert_Update_NodeType) as well as make the class perform data validation before saving data.

Answer 2

I am not that familiar with SQL Server, but I know with Oracle you can specify Constraints that you could use to do what you are looking for. I am pretty sure you can define constraints in SQL server also though.

EDIT: I found this link that seems to have a lot information, kind of long but may be worth a read.

Answer 3

You can set up some insert/update triggers. Just check if these fields are null or notnull, and reject insert/update operation if needed. This is a good solution if you want to store all the data in the same table.

You can create also create a unique table for each classes as well.

Answer 4

Have you tried NHibernate? It's much more matured product than Entity Framework. It's free.

Answer 5

Use CHECK constraints on the table. These allow you to use any kind of boolean logic (including on other values in the table) to allow/reject the data.

From the Books Online site:

You can create a CHECK constraint with any logical (Boolean) expression that returns TRUE or FALSE based on the logical operators. For the previous example, the logical expression is: salary >= 15000 AND salary <= 100000.