More Java Non-sense
I have reached a point where I can no longer move forward in my learning until I sort out a few things. The Philips AI tutorials talks about Entities
and EntityManagers
. I have no clue what either of those things are so in this post I will discuss my findings
Class, Objects, and Entities: what’s the difference?
According to stackoverflow, a class
is a template for creating objects
Objects
are a bundle of data that is packaged with functions that act on that data (called methods)
Entities
is an object that represents something that has an identity that the system is interested in such as customers and/or accounts. Entities
are annotated as an Entity
. Also, Entities
represent a table in a relational database, and each entity represents a row in that table.
Entity Manager
is an api for accessing database ina particular unit of work. It is used to create and remove persistent entity instances, to find entities by their primary key id, and to query over all entities.
Persistence Context
is a set of entity instances that is managed by the entity manager.