java - What is the name (or keywords) of methodology/technique to hold ids instead of related entities in entity? -

entity hold data mapped data persistent storage. db.

you can hold ids:

class book {     private string title;     public string gettitleid() { return title; }      private long publisherid;   // <==  **it is**!     public long getpublisherid() { return publisherid; }      private list<long> authorids;     public list<long> getauthorids() { return authorids; } } 

or resolved entities:

class book {     private string title;     public string gettitleid() { return title; }      private publisher publisher;   // <==  **it is**!     public publisher getpublisher() { return publisher; }      private list<author> authors;     public list<author> getauthors() { return authors; } } 

if use orm hibernate working resolved entities simple orm *join*s related entities free.

but if concern on performance or want use db features move logic java sql manual sql queries entities ids win (they faster , annoying join each related entities manually)!

so decide maintain 2 type of entities: ids , resolved related entities hold knowledge in data type (in type name).

so start googling best suffixes class names can't find appropriated keywords. please tell me how name of methodology/tecnichue hold ids vs related entities in entity!

i think terms looking

eager versus lazy loading , fetching strategies.

see

• entity framework loading related entities
• a short primer on fetching strategies

edit:

the lazy-loaded entity can referred proxy, not-yet-initialized collection wrapper.

in reaction comments: see hibernate one-to-one: getid() without fetching entire object. hibernate can produce id values lazy loaded entities.

from hibernate faq:

how can retrieve identifier of associated object, without fetching association?

just it. following code not result in select statement, if item association lazy.

long itemid = bid.getitem().getid(); 

this works if getitem() returns proxy , if mapped identifier property regular accessor methods. if enabled direct field access id of item, item proxy initialized if call getid(). method treated other business method of proxy, initialization required if called.