JPA object link ing

Onetoone

 

 
Public classemployee implements serializable {...... @ Onetoone (cascade = cascadetype. All, orphanremoval = true, fetch = fetchtype. Lazy) @ joincolumn (name = "addr_id") Private Address ;... ...}
 

 

 

Manytoone

 

 
Public classemployee implements serializable {...... @ Manytoone (fetch = fetchtype. lazy) @ jointable (name = "emp_job", joincolumns = @ joincolumn (name = "emp_id"), inversejoincolumns = @ joincolumn (name = "title_id ")) // keys are connected to the primary keys column of the table joincolumns primary test master table, the inversejoincolumns primary test field, or the private jobtitle column of the primary keys column of the table generated by attention; @ manytoone (fetch = fetchtype. lazy) @ joincolumn (name = "manager_id") private employee manager ;... ...}
 

 

 

Onetoworkflow

 

 
Public classemployee implements serializable {...... @ Onetomany (mappedby = "manager") // The manager field private list <employee> managedemployees = newarraylist <employee> (); @ onetomany (mappedby = "owner ", cascade = cascadetype. all, orphanremoval = true) Private list <phonenumber> phonenumbers = newarraylist <phonenumber> (); @ onetoworkflow (cascade = cascadetype. all, orphanremoval = true) @ joincolumn (name = "emp_id") Private list <degree> degrees = newarraylist <de Gree> ();......}
 

 

 

Manytoyun

Public classemployee implements serializable {...... @ Manytomany // @ jointable (name = "proj_emp", joincolumns = @ joincolumn (name = "emp_id"), inversejoincolumns = @ joincolumn (name = "proj_id ")) private list <project> projects = newarraylist <project> ();... ...}
 

 

 

Joint primary key ing

Manytoone onetow.manytoyun ing, And the jointable ing will show the joint primary key, that is, the double primary key.