hibernate - Grails域错误: “USER_GROUP_ID”列不允许使用NULL

Question

我试图创建一个SecUser域对象，其中包含UserGroup对象的集合。每个UserGroup应具有一个创建者，该创建者是SecUser的一种。 UserGroup还包含SecUsers的集合(例如，Facebook风格应用程序上创建者的 friend 集合)。到目前为止，我有以下域类...

class SecUser implements Serializable {
  static constraints = {
    ....
    usergroups nullable: true
  }
  static mapping = {
    ...
    usergroups cascade: 'all-delete-orphan'
  }
  static hasMany = [
    ...
    usergroups: UserGroup
  ]
}

class UserGroup {
  SecUser creator;
  static belongsTo = SecUser;
  static hasMany = [
    members : SecUser
  ]
  static constraints = {
    creator nullable: false
    members nullable: true, maxSize: 100
  }
}

在 Bootstrap.groovy中，我尝试像这样创建一些 SecUser和 UserGroup对象...

def secuser = new SecUser(username: "username", password: "password");
def group1 = new UserGroup(title: "Friends", description: "friends");
def group3 = new UserGroup(title: "Colleagues", description: "colleagues");
secuser.addToUsergroups(group1);
secuser.addToUsergroups(group2);

但是我遇到一个错误，它说...

ERROR spi.SqlExceptionHelper  - NULL not allowed for column "USER_GROUP_ID"; SQL statement:
insert into sec_user_usergroups (sec_user_id, creator_id) values (?, ?) [23502-176]
Error |
2015-07-28 11:04:49,208 [localhost-startStop-1] ERROR context.GrailsContextLoaderListener  - Error initializing the application: Hibernate operation: could not execute statement; SQL [n/a]; NULL not allowed for   column "USER_GROUP_ID"; SQL statement:
insert into sec_user_usergroups (sec_user_id, creator_id) values (?, ?) [23502-176]; nested exception is org.h2.jdbc.JdbcSQLException: NULL not allowed for column "USER_GROUP_ID"; SQL statement:
insert into sec_user_usergroups (sec_user_id, creator_id) values (?, ?) [23502-176]
Message: Hibernate operation: could not execute statement; SQL [n/a]; NULL not allowed for column "USER_GROUP_ID"; SQL statement:
insert into sec_user_usergroups (sec_user_id, creator_id) values (?, ?) [23502-176]; nested exception is org.h2.jdbc.JdbcSQLException: NULL not allowed for column "USER_GROUP_ID"; SQL statement:
insert into sec_user_usergroups (sec_user_id, creator_id) values (?, ?) [23502-176]

我猜该程序告诉我它无法完成 addToUsergroups操作，因为 UserGroup尚未获得 id(因为尚未保存)。但是，有没有一种方法可以在没有 addToUsergroups的情况下完成 id操作？ (因为没有 UserGroup不应创建 SecUser)。还是我的域对象的设计有问题？

提前致谢!

Answer 1

我猜您在UserGroup表中的PK列称为USER_GROUP_ID，如果这就是您的所有代码，则您什么都没说，并且数据库中存在一个约束，不允许您将其保留为空。因此，您必须更改UserGroup ID，以指定PK列的调用方式不同。

class UserGroup {
  SecUser creator;
  static belongsTo = SecUser;
  static hasMany = [
    members : SecUser
  ]

  static mapping = {
    id column: 'user_group_id'
  }

  static constraints = {
    creator nullable: false
    members nullable: true, maxSize: 100
  }
}

希望能帮助到你。