使用静态表休眠一对一映射

Question

According to my requirement, I have a Rate Master table where some criteria wise rate is defined. This is static table and does not change on transaction basis.Now whenever user register to the system they subscribe for a specific plan(Rate) and in subscription table we store the user details along with with rate wise subscription they have chosen.

**Table Details:**
**Rate Master Table -** 
rate_id- INT -Auto generated.
Amount - INT

**Subscription table -** 
ID - INT -Auto generated.
User_ID - VARCHAR - USER ID (No relation with user table)
Rate_Id - INT - RATE MASTER table ID (Though this only hibernate will fetch all the records of Rate)

Now please help me how this mapping should be done on Hibernate POJO side. For individual table wise pojo everything is working as expected but when I am doing relationship in Subscription pojo, system forcing me to mark insertable=false,updatable=false. So, please help me with the Subscription table POJO and process to do it without updating rate table in every subscription update. Note: This relation will be uni-directional subscription table to rate mapping only.

@Column(name = "rate_id",insertable=false,updatable=false)
private int rateId;
@OneToOne(targetEntity = RateMaster.class, cascade = CascadeType.ALL)
@JoinColumn(name = "rate_id", referencedColumnName = "rate_id")
private RateMaster rateMaster;

Thanks in advance.

Answer 1

Hibernate insists on insertable=false,updatable=false because the rateId field is mapped to the same column that is used as a join column for the relationship with the RateMaster entity. You have thus introduced a redundancy, and Hibernate cannot promise to preserve any inconsistent data you introduce through that redundancy.

My recommendation would be to just ditch the rateId field altogether. Manage the underlying column via the RateMaster entity assigned to each Subscription . If necessary, introduce a read-only, non-persistent accessor on Subscription that provides the rateId by obtaining it from the RateMaster .