Hello everybody,
today I want to boast about one new phrase in my vocabulary:
impedance mismatch.
It means the following: difference between what you have in your C# code ( as example ) and have that is persisted in db.
For example if you have client, which has orders, and each order thas items, but in C# you'll have clinet, which has list of orders and each order will have list of items, than you can really understand what is impedance mismatch.