java - Hibernate - Either field A OR B can be null but one of A or B must not be null -

is possible in hibernate model use case in have 2 fields , either of them null @ least 1 of them must not null? below code have @ moment don't fact have set both of them @column(nullable = true). in case want either personal email address or work address. there way support this? or alternative approach needed?

public class applicantdetails {      //...      @onetoone(optional = false)     private contactdetails contactdetails;      //... }  public class contactdetails {      @id     @generatedvalue(strategy = generationtype.auto)     private integer id;      /*need @ least 1 email address doesn't matter one.*/     @column(nullable = true, unique = true)     private string personalemail;      @column(nullable = true, unique = true)     private string workemail;      //...  } 

i recommend anyway define check constraint in database if database supports form of it:

check (personal_email not null or work_email not null) 

regarding middle layer, can write own validators in services store/update contactdetails , raise corresponding exceptions if attempts store/update inconsistent state made, or can use validation framework hibernate validator.

a quick workaround utilise entity lifecycle callback methods:

@prepersist @preupdate private void validate() {   if (personalemail == null && workemail == null) {     throw new validationexception();   } }