java - How to search mySql database table by foreign key using JPA? -

i have 2 classes (businessaccount , projects (shown below) mapped mysql database) 1:m relationship exists between businessaccounts , projects. inserting data database having problem when comes querying database. problem having have no getter or setter foreign key, 'contractor_id' in projects class. query want carry out return list of names of projects given businessaccount, searching foreign key reference in projects table. can no problem in mysql there no reference contractor_id java entity in projects class, i'm not sure how search within java class. (note: tried declare foreign key along getters , setters in projects class have these mapped 1:many relationship in class already, wouldn't compile flagged duplicate entities.) i'm sure it's obvious i'm missing appreciated!

public list<projects> getprojectlist() {     factory = persistence.createentitymanagerfactory(persistence_unit_name);     entitymanager em = factory.createentitymanager();        list<projects> projectlist = new arraylist<projects>();          em.gettransaction().begin();          string sessionemail=util.getemail();         query myquery = em.createquery("select u businessaccount u u.email=:email");         myquery.setparameter("email", sessionemail);          list<businessaccount> userlist=myquery.getresultlist();         businessaccount account =userlist.get(0);          query myquery2 = em.createquery("select distinct p.* businessaccount u "                 + "inner join projects p on p.contractor_id=:userid");  /*note p.contractor_id above refers entity in  mysql database (and won't work obviously), want refer  it's java equivalent not sure how that*/          myquery2.setparameter("userid", account.getid());         projectlist=myquery2.getresultlist();         em.gettransaction().commit();         em.close();          return projectlist;      }    @entity @table(name = "business_accounts") public class businessaccount {      @id     @generatedvalue(strategy = generationtype.identity)     private int id;      @column(name = "first_name")     private string firstname;      @column(name = "surname")     private string surname;          @onetomany(mappedby = "businessaccount", fetch = fetchtype.eager, cascade = { cascadetype.all })     private list<projects> projects;      public int getid() {     return id;     }      public void setid(int id) {     this.id = id;     }      public string getfirstname() {     return firstname;     }      public void setfirstname(string firstname) {     this.firstname = firstname;     }      public string getsurname() {     return surname;     }         public list<projects> getprojects()     {     if (projects == null)     {         projects = new arraylist<projects>();     }      return projects;     }     public void setprojects(list<projects> projects)     {     this.projects = projects;     }      }   @entity @table(name = "projects") public class projects {  @id @generatedvalue(strategy = generationtype.identity) private int project_id;  @column(name = "project_name") private string projectname;  @manytoone(fetch = fetchtype.lazy) @joincolumns({ @joincolumn(name = "contractor_id", referencedcolumnname="id") }) private businessaccount businessaccount;   public businessaccount getbusinessaccount() {     if (businessaccount == null) {         businessaccount = new businessaccount();     }     return businessaccount; }  public void setbusinessaccount(businessaccount businessaccount) {     this.businessaccount = businessaccount; }  public int getproject_id() {     return project_id; }  public void setproject_id(int project_id) {     this.project_id = project_id; }  public string getprojectname() {     return projectname; }  public void setprojectname(string projectname) {     this.projectname = projectname; }  } 

the jpa query (you need use relation property, no need foreign key - please try, may need tweaking):

select p businessaccount u, in(u.projects) p u.id=:userid 

but need query? can related projects property:

businessaccount account = ... list<projects> projectlist = account.getprojects();