Hibernate: Parent/Child relationship in a single-table

Posted by Dee on Stack Overflow See other posts from Stack Overflow or by Dee
Published on 2010-03-11T05:57:11Z Indexed on 2010/03/11 5:58 UTC
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I hardly see any pointer on the following problem related to Hibernate. This pertains to implementing inheritance using a single database table with a parent-child relationship to itself. For example:

CREATE TABLE Employee (
  empId BIGINT NOT NULL AUTO_INCREMENT,
  empName VARCHAR(100) NOT NULL,
  managerId BIGINT,
  CONSTRAINT pk_employee PRIMARY KEY (empId)
)

Here, the managerId column may be null, or may point to another row of the Employee table. Business rule requires the Employee to know about all his reportees and for him to know about his/her manager. The business rules also allow rows to have null managerId (the CEO of the organisation doesn't have a manager).

How do we map this relationship in Hibernate, standard many-to-one relationship doesn't work here? Example code would be appreciated.

Hibernate: Parent/Child relationship in a single-table

Posted by Dee on Stack Overflow See other posts from Stack Overflow or by Dee
Published on 2010-03-11T05:55:59Z Indexed on 2010/03/11 5:58 UTC
Read the original article Hit count: 525

Filed under:

hibernate

|

single-table-inheritance

I hardly see any pointer on the following problem related to Hibernate. This pertains to implementing inheritance using a single database table with a parent-child relationship to itself. For example:

CREATE TABLE Employee ( empId BIGINT NOT NULL AUTO_INCREMENT, empName VARCHAR(100) NOT NULL, managerId BIGINT, CONSTRAINT pk_employee PRIMARY KEY (empId) )

Here, the managerId column may be null, or may point to another row of the Employee table. Business rule requires the Employee to know about all his reportees and for him to know about his/her manager. The business rules also allow rows to have null managerId (the CEO of the organisation doesn't have a manager).

How do we map this relationship in Hibernate, standard many-to-one relationship doesn't work here? Example code would be appreciated.

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