I've read multiple tutorials about core data but most of them have to do with basic setup.. I hope ill learn more each day about it. Cuz it made somethings very simpler. Though the absolute control that sqlite gives was a bit of a tradeoff.. but maybe I'm completely wrong! Here I'm trying to fetch things differently.. Lets say I'm trying to RECORD as well as calculate results based on values stored in core data. Lets take Enery equation : E=mc(square) I have three entities, Parent/Child/RecentRecords **A Category's entity** Category -Name : Einstein's equation -E = mc2 **Child Entity:** - Name: Mass another entry: - Name:LightSpeed (for the sake of example, lets say the speed of light is not constant. Recent Entity: The purpose of this entity is to store and track the Child Entities and so it has: -NSDate TimeStamp -NSNumber: Value -Relationship <---->>ChildEntity I'll explain from a User's point of view, If I tap "Einstain's equation" (Category/Parent Entity), the detail view will bring out 2 textfields by iterating through the Child entity. When I record my entries of mass, light speed, it should be saved in the Recent entity. SO that overtime i can have a bunch of recordings. Now image a similar setup for another formula, v=U+at. where Velocity would be parent. U, a, t would be in CHild entity. And in one recording a user would add three Recent Entity objects. My question is I want to find out if theres an efficient way to calculate the results/entries at the Parent/Category entity level. Because, EinstainsEquation stores the formula of its child entities, E=mc2 and V=u+at. The thing thats making this complicated is fetching the entries from the recent Entity based on timestamp (recording) and calculating it and showing the result based on the most recent entries. Code: Parent<-------->>Child<-------->>Recent -Einstein <---->>Mass <----------->>Multiple Mass recordings based on time -mc2 LightSpeed <------>>Multiple Lighspeed records based on time -Velocity<------>>U <--------->>Multiple entries based on time of all 3. -u+at Aceleration TimeTaken Based on the graph above, I need to get einstein result FROM the most recent entries of mass/lightspeed and calculate each of those entries with its formula mc2. I thought of having a transient Property in Parent entity, how would i go about accomplishing this? How can i use the formula and calculate the child values of recent entity. Im kinda lost here..