Whatever the result, the issue is not with EF. Sounds to me like someone went mad with denormalization.
Conceptually how you deal with a model with 800 classes is going to be hard, you would be best to group the tables by functionality, or refactor the database if it is young
As in most real world situations, the database comes as a given to me from the year 14 B.C. It was first created then by the Barbarians and then immediately dropped as it was too heavy a load for them to carry.
Activity on it resumed a couple of a hundred years later when King Chatushpada of the Mauryan empire defeated the Mughals in Delhi and began his reign. Right then, on another side of the world, some people were busy finding Columbus while he went to find a piece of land.
Our beloved database came back to life precisely then. This time, when the year was 1497, it was graciously re-created, and in a spur of kindness, left over in posterity by a dozen or so excited African monkeys who recorded their observations of Lord Kelvin as he sailed through the Atlantic collecting a variety of rocks.
You're right. Someone went mad. But it wasn't me.
A hint of relief, albeit just a hint, is that there's a lot of junk tables in the database and I probably won't be needing about half of them. But still, even a half of them are as strong as the whole.