How to prevent changes of entity relationships?

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I am using spring boot for to store complex json-structures via JPA in our database.

The root of the json-structure represents a "House" object. A "House" object contains several "Furnitures". For example:

House ID: 4711
|- Furniture: ID 4712 (with confidential information)

Users have read/write permissions for certain Houses, and all their "Furnitures".

My problem is, that through the REST-API, the user can "steal" Furnitures from other Houses, if he knows their primary keys; with request like this one:

POST http://localhost:8080/house

{
    houseId: 99991337,
    furnitures: [{
        furnitureId: 4712,
        ...
    }]
}

This leads to:

House ID: 4711
|- empty!

House ID: 99991337
|- Furniture 4712 (with confidential information)

Althought the user did not have permission to House 4711, he "unlinked" Furniture 4712 from House 4711 and instead linked it to House 99991337.

How can I prohibit the change of the House of a Furniture?

In the JPA-Entities, there is a bidirectional OneToMany-Relationship from House to Furniture. I thought of maybe searching in the database any Furniture of incoming requests, check all permissions on all of them. But I would prefer to only have to check the permission on the House (because in real life, I have many more entities like Furniture)


If my understanding is correct, just search the permissions table by userId and houseId that was provided in the request. If there is a match, then the user has permissions to change the houseId.

Depending on the permissions you can either set or not set houseId to the object that you are about to save to the database.

If you still want the user to change the furniture data then you can save only furniture entity by providing furnitureId and text for the new Furniture() object.

How do I stop Entity Framework from trying to save/insert child , If I manually set the properties to null, I get an error "The operation failed: The relationship could not be changed because one or more of the  Entity framework supports three types of relationships, same as database: 1) One-to-One 2) One-to-Many, and 3) Many-to-Many. We have created an Entity Data Model for the SchoolDB database in the Create Entity Data Model chapter. The following figure shows the visual designer for that EDM with all the entities and relationships among them.


First of all your request structure is incorrect. For secure reasons like this you could not ask to user for his userid, houseid etc.. You need to handle it in background without relying to user request.

But for this situation you can simply change the insert statement with a select insert. Join the permission table to select statement to check given id is attached to related user. If nothing inserted user tries to insert illegal id.

How to prevent changes of entity relationships?, I am using spring boot for to store complex json-structures via JPA in our database. The root of the json-structure represents a "House" object. Synchronizing the changes between the foreign keys and navigation properties. When you change the relationship of the objects attached to the context by using one of the methods described above, Entity Framework needs to keep foreign keys, references, and collections in sync.


I think you can try to put handler on update of Furniture entity table with annotation @HandleBeforeSaveand @RepositoryEventHandler and inside this handler you can query only this Furniture entity and check which House it belongs. And then decide what to do with this update request

Chapter 8 The Entity Relationship Data Model – Database Design , The entity relationship (ER) data model has existed for over 35 years. It is well suited to data We want to keep track of the dependents for each employee. Each dependent has a name, It can be changed into two 1:M relationships. It can be  Each referencing entity in a 1:N entity relationship has one referencing attribute where the relationship can be considered parental. For example, if you create a new custom entity and add a 1:N entity relationship with the account entity where your custom entity is the referencing entity, you can configure the actions for that entity relationship to use the options in the Parental column.


If the following statement holds true:

Yes, a furniture should belong to exactly one house and should be privately be owned by that house. Only those users permitted to see/edit the house should be able to see/edit its furniture.

In my mind it means you should not be allowed to create a house with furniture that is already attached to another house (Business requirement).

I would check first if the furniture doesn't belong to another house before creating the house (preserve data integrity) and throw an exception if it does. I see this happening in the business layer, which will cater for any outer boundary call which might compromise the data/requirement.

You could move it outside your business layer, but then the possibility is there that you might duplicate code per channel or miss one/two channels.

Entity relationships overview for Common Data Service, Entity relationships are metadata that make changes to the database. Prevent deleting the primary entity so that the related entity records can  You can remove a relationship by setting a reference navigation to null, or removing the related entity from a collection navigation. Removing a relationship can have side effects on the dependent entity, according to the cascade delete behavior configured in the relationship.


Entity relationship behavior (Developer Guide for Dynamics 365 , When a one-to-many entity relationship exists there are cascading Restrict, Restrict, Prevent the Referenced entity record from being deleted when The cascade actions related to the reparent action refer to changes to  Entity Framework is still locked, step by step, to the way the underlying data store works. In SQL Server, this means join performance, view and index utilization, stored procedure calls, and so on. This like calling a latex glove on a hand an abstraction for a hand.


[PDF] Entity-Relationship Model, entity set. ◇ Attributes are simple values, e.g. integers or character strings, not structs, sets, etc. Page 5. 5. E/R Diagrams. ◇In an entity-relationship diagram: ◇ Entity set Avoid redundancy. 2. become inconsistent if we change one and. The most common pattern for relationships is to have navigation properties defined on both ends of the relationship and a foreign key property defined in the dependent entity class. If a pair of navigation properties is found between two types, then they will be configured as inverse navigation properties of the same relationship.


Bookshelf v7.8: Documenting Your Changes in an ERD, These changes should be documented in an Entity-Relationship Diagram (ERD). Figure 28 They do not reshape themselves to avoid other lines or entities. Learn how to create an Entity Relationship Diagram in this tutorial. We provide a basic overview of ERDs and then gives step-by-step training on how to make an ER diagram with correct cardinality