Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.idea.MAE_MFEView

Question

Why am I getting this exception? ``` package com.domain.idea; import javax.persistence.CascadeType; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.JoinColumn; import javax.persistence.OneToOne; import javax.persistence.Table; import org.hibernate.annotations.AccessType; /** * object model for the view [InvestmentReturn].[vMAE_MFE] */ @Entity @Table(name="vMAE_MFE", schema="InvestmentReturn") @AccessType("field") public class MAE_MFEView { /** * trade property is a SuggestdTradeRecommendation object */ @OneToOne(fetch = FetchType.LAZY , cascade = { CascadeType.PERSIST }) @JoinColumn(name = "suggestedTradeRecommendationID") private SuggestedTradeRecommendation trade; /** * Most Adeverse Excursion value */ private int MAE; public int getMAE() { return MAE; } /** * Most Favorable Excursion value */ private int MFE; public int getMFE() { return MFE; } /** * @return trade property * see #trade */ public SuggestedTradeRecommendation getTrade() {…

Accepted Answer

You are missing a field annotated with `@Id`. Each `@Entity` needs an `@Id` - this is the primary key in the database.

If you don't want your entity to be persisted in a separate table, but rather be a part of other entities, you can use `@Embeddable` instead of `@Entity`.

If you want simply a data transfer object to hold some data from the hibernate entity, use no annotations on it whatsoever - leave it a simple pojo.

Update: In regards to SQL views, Hibernate docs write:

There is no difference between a view and a base table for a Hibernate mapping. This is transparent at the database level

Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.idea.MAE_MFEView

Solution

Problem