Running a database without constraints We're looking at utilizing a new proprietary high performance database engine for OLAP and OLTP scenarios. One important aspect of it right now is that it does not support foreign key or other constraints. What is your opinion on whether this limitation should be considered a non-starter for OLTP applications? 

Would it be crazy to think about implementing our own referential integrity checks for any inserts, updates, and deletes?
Rolling your own referential integrity checks has the following disadvantages:


Speed - Your own checks will never be as fast as database internal checks.
Completeness- There is always the possibility when you roll your own that you will miss something.


The speed issue is acceptable if the high performance of the database engine can make up for the loss, but the potential for a loss of data integrity using your own checks would still be a concern.