java - Hibernate - how to use cascade in relations correctly -

i'm using hibernate in spring mvc application , have question cascade. see many similar questions it, none of them can answer question. suppose have user , userposition objects. user has collection of userposition , has 1 userposition default position. structure this:

user:

@onetomany(mappedby = "user", fetch = fetchtype.lazy) private collection<userposition> userpositioncollection;  public collection<userposition> getuserpositioncollection() {     return userpositioncollection; }  public void setuserpositioncollection(collection<userposition> collection) {     this.userpositioncollection = collection; }    @onetoone(fetch = fetchtype.lazy, cascade = cascadetype.all) @joincolumn(name = "default_user_position_id", referencedcolumnname = "id") private userposition defaultuserposition;  public userposition getdefaultuserposition() {     return defaultuserposition; }  public void setdefaultuserposition(userposition defaultuserposition) {     this.defaultuserposition = defaultuserposition; } 

userposition:

@joincolumn(name = "user_id", referencedcolumnname = "id") @manytoone(fetch = fetchtype.lazy, cascade = cascadetype.persist) private user user;  public user getuser() {     return user; }  public void setuser(user user) {     this.user = user; }  @onetoone(fetch = fetchtype.lazy, mappedby = "defaultuserposition", cascade = cascadetype.persist) private user defaultuserposition;  public user getdefaultuserposition() {     return defaultuserposition; }  public void setdefaultuserposition(user defaultuserposition) {     this.defaultuserposition = defaultuserposition; } 

now, question what's best practice use cascade saving related objects?. in fact, confused these 3 solutions:

solution 1:

user user = new user(); //some setters , getters  userposition userposition = new userposition(); //some setters , getters  list<userposition> positionlist = new arraylist<>(); positionlist.add(userposition); user.setdefaultuserposition(userposition); user.setuserpositioncollection((collection<userposition>) positionlist ); session.persist(user) 

solution 2:

user user = new user(); //some setters , getters  userposition userposition = new userposition(); //some setters , getters  userposition.setuser(user); userposition.setdefaultuserposition(user); session.persist(userposition) 

solution 3(combination of 2 previous solutions):

user user = new user(); //some setters , getters  userposition userposition = new userposition(); //some setters , getters  list<userposition> positionlist = new arraylist<>(); positionlist.add(userposition); user.setdefaultuserposition(userposition); user.setuserpositioncollection((collection<userposition>) positionlist ); userposition.setuser(user); userposition.setdefaultuserposition(user); session.persist(user); 

this important me, please me. solution correct , should cascade property? thank time.

the user parent entity , cascading always propagates parent child entities.

therefore, user associations become:

@onetomany(mappedby = "user",      fetch = fetchtype.lazy,      cascade = cascadetype.all,      orphanremoval = true) private collection<userposition> userpositioncollection; 

but default position, user becomes child of association:

@onetoone(fetch = fetchtype.lazy) @joincolumn(name = "default_user_position_id", referencedcolumnname = "id") private userposition defaultuserposition; 

in userposition class other way around:

@joincolumn(name = "user_id", referencedcolumnname = "id") @manytoone(fetch = fetchtype.lazy) private user user; 

and

@onetoone(fetch = fetchtype.lazy,      mappedby = "defaultuserposition",      cascade = cascadetype.persist) private user defaultuserposition; 

then have add following utility methods synchronize both sides. these go user class:

public void adduserposition(userposition userposition) {     userpositioncollection.add(userposition);     userposition.setuser(this); }  public void adddefaultuserposition(userposition userposition) {     defaultuserposition = userposition;     userposition.setdefaultuserposition(this); } 

the persisting logic becomes:

user user = new user(); //some setters , getters  userposition userposition = new userposition(); //some setters , getters   user.adduserposition(userposition); user.setdefaultuserposition(userposition);  session.persist(user);