entity-relationship

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Replace entities in to-many relationship in Core Data

When I retrieve an entity from the one side of a one-to many relationship, I create a mutable array from the set that is the collection of entities from the relationship. I manipulate, edit or otherwi[详细]

2023-03-26 11:56 分类：问答
EF4.1 Code First, Navigation Property across multiple mapping joins

In SQL, I have a 1:1 relationship defined between 2 tables which are linked by 2 mapping tables, four in total. I have no influence on the database schema.[详细]

2023-03-26 10:41 分类：问答
EF with Inheritance with concrete classes

I have set of entities with some level of inheritance. abstract class A { ... } class B: A //Non abstract B[详细]

2023-03-26 09:16 分类：问答
What's the difference between property Entity Reference and property in Entity Data Model?

I have three tables structure like following AppUserUserApp ********************* AppUserIdUserIdAppId UserId[详细]

2023-03-25 19:10 分类：问答
CoreData error with self referential relationship

I have an entity with a relationship with itself. I have declared a first to-many relationship named children. And a one to one named parent.[详细]

2023-03-25 18:28 分类：问答
How to define a to-self relationship that's to-many only one way using Core Data?

In a vector graphics manipulation program, I have a \"Group\" entity which specifies groups of graphics and other groups. A Group can belong to only one other Group, but can contain many other Groups.[详细]

2023-03-25 10:55 分类：问答
Implementing super-type subtype correctly in MySQL

Below is a diagram of a database in which I am trying to determine the appropriate design for. Here are a few notes.[详细]

2023-03-25 09:56 分类：问答
Defining Many-to-Many Association in Entity Framework

I have th开发者_如何学Ce following tables in my edmx : Errors Id, Description, solved, officeId, siteId[详细]

2023-03-24 16:15 分类：问答
Version of all children is incremented in OneToMany when merging parent entity

I have a OneToMany relationship defined like this: @Entity Parent extends BaseEntity { @OneToMany(mappedBy = \"parent\", fetch = FetchType.LAZY, cascade = { CascadeType.PERSIST, CascadeType.REFRESH,[详细]

2023-03-24 16:02 分类：问答
How can I improve this database model?

I\'m trying to model the relationship of dvd sales and dvd rentals to a customer. Although I dont think my transction table is correct. If anyone can let me know if I\'m goin in the right direction wi[详细]

2023-03-24 14:48 分类：问答