Foreign key referencing a view in Oracle

Question

Hi everyone,

I'm attempting to reference a view with a foreign key but I am getting this error:

"Error: ORA-02270: no matching unique or primary key for this column-list"

However, I have created a primary key on this view and verified it in the Constraints tab in TOAD.

This is the table I'm attempting to create:

CREATE TABLE QUESTION
(   
    QUESTION_ID             INTEGER not null,
    CREATED_USER_ID         INTEGER not null,    
    CONSTRAINT PK_QUESTION  PRIMARY KEY (QUESTION_ID),
    CONSTRAINT FK_USER
        FOREIGN KEY (CREATED_USER_ID)
        REFERENCES SOME_VIEW(VIEW_ID)
);

SOME_VIEW is a view based on another view which points to the employee table in another schema.

Answer 1

The foreign key against a view is probably what's causing the trouble.

Answer 2

Regardless the possibility of creating foreign keys to views, it is indeed not the best idea to implement.

Database views were designed to let user comfortably query some data he needs, but at the same time to serve as a security barrier, to conceal all database structure, including tables, data constraints in tables, and, yes, also table cross-references.

So, a good practice to me would be to reference an existing table from a your new one, despite its residence in other scheme.