Hibernate / JPA-删除具有@OneToMany关系的表（一个父级-0或多个相同类型的子级）违反了外键约束

Question

I have a problem when trying to delete a table with @OneToMany relationship to table created
from the same java class using

Query q = getEntityManager().createQuery("DELETE FROM " + entityClass.getSimpleName());
q.executeUpdate();

Here's the table:

    CREATE TABLE p_data_group
(
  data_group_id bigint NOT NULL,
  description character varying(350),
  description_eng character varying(350),
  multiplicity_max integer,
  multiplicity_min integer,
  name character varying(35),
  name_db character varying(30),
  name_eng character varying(35),
  name_xml character varying(35),
  path character varying(1024),
  "position" integer,
  is_root boolean,
  parent_group_id bigint,
  CONSTRAINT p_data_group_pkey PRIMARY KEY (data_group_id ),
  CONSTRAINT fk_data_group_parent_group_id FOREIGN KEY (parent_group_id)
      REFERENCES p_data_group (data_group_id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION
)
WITH (
  OIDS=FALSE
);
ALTER TABLE p_data_group
  OWNER TO postgres;

And here's the part of the class that represents relations:

@ManyToOne
@JoinColumn(name = "parent_group_id", insertable = false, updatable = false)
@XmlTransient
public DataGroup getParentDataGroup() {
    return parentDataGroup;
}

@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "parent_group_id")
@ForeignKey(name = "fk_data_group_parent_group_id")
@Index(name = "idx_data_group_parent_group_id")
@LazyCollection(LazyCollectionOption.FALSE)
@XmlElementWrapper
public List<DataGroup> getChildDataGroups() {
    return childDataGroups;
}

Now when trying to delete to root table all others should be deleted as well according to CascadeStyle.ALL annotation :

PSQLException: ERROR: update or delete on table "cpdm01" violates foreign key constraint "fk_cpdm01_kodpkd_cpdm01_id" on table "cpdm01_kodpkd" Detail: Key (cpdm01_id)=(100) is still referenced from table "cpdm01_kodpkd".

Am I right here?

Answer 1

As per your Error log shows

DETAIL: Key (cpdm01_id)=(100) is still referenced from table "cpdm01_kodpkd".

There is still a record referencing to cpdm01_id 100. You might delete record in cpdm01_kodpkd with cpdm01_id = 100 before , but there might be others as well. You have to delete all records in cpdm01_kodpkd referencing to cpdm01_id 100 in main_order. If not, the database protects you from doing harm to your data.