![]() ![]() Thanks Ivan, However, correct me if I am wrong, I guess in the code for data annotations you forgot to comment out the two earlier ForeignKey lines I had incorrectly inserted and the single line of composite key would be enough. If you want House to refer to Area, the foreign key should consist of the same fields as Areas composite key, otherwise EF wont accept the mapping.A work-around could be to skip the mapping and to join the entities manually when necessary, but that conceals the real issue: poor design. And it will still generate Fluent API so EF Core is also happy. The Customer can be identified by the Composite Key Source System (SrcSys) & Customer ID (CustId). You wont be able to map this correctly in EF. Then your scaffolding code would KeyAttribute for composite key so OData is happy. You can copy this file and change below code and replace the service to get behavior you desire.Īll you need is to remove the check for 1 property. If you want to got bit crazy (warning: internal code so it can break between EF core releases): If the foreign key is a composite key (has more than one property). But I was commenting that it would not be good idea to EF to write some code which can be misleading. You could've applied the ForeignKey data annotation to the foreign-key property. It is just matter of scaffolding KeyAttribute which would be ignored by EF. In your particular case, we can scaffold the code which would work with OData & it would still work with EF Core. This issue particularly talks about support for KeyAttribute at runtime. ![]() There are two ways to implement Uniqueness or Unique Key attribute on a model property in ASP. In previous versions of Entity Framework, you would use the HasDatabaseGenerated method with the DatabaseGenerated.None enumeration to achieve the same outcome as the Entity Framework core ValueGeneratedNever method.- I just wanted to clarify 2 different aspect. This is the end of 'Best ways of implementing Uniqueness or Unique Key attribute on a model property in ASP. The Data Annotations attribute equivalent of the ValueGeneratedNever method is the DatabaseGenerated attribute with the None option. Others may require manual configuration such as setting default values or triggers. Some primary keys consist of more than 1 entity attribute or database column. This MS doc article - Alternate Keys (Unique Constraints) - will explain how to use and which. Some will generated values for selected data types such as Identity, rowversion, GUID. There are no data annotations to realize a unique constraint. Database providers differ in the way that values are automatically generated. See the performance docs for more information. To see all the basic instructions and complete navigation for this series, visit Entity Framework Core with ASP.NET Core Tutorial. Indexes over multiple columns, also known as composite indexes, speed up queries which filter on indexs columns, but also queries which only filter on the first columns covered by the index. You can download the source code for this article on our GitHub repository. ![]() Data Annotations - Key Attribute in EF 6 & EF Core. Public DateTime DateCreated Įntity Framework Core does not implement a value generation strategy. We are going to use all three ways: by Convention, Data Annotations, and Fluent API, to create those relationships. Configures the primary key property(s) for this entity type. Protected override void OnModelCreating(ModelBuilder modelBuilder) This is useful if you want to circumvent the database's default behaviour. The Entity Framework Core Fluent API ValueGeneratedNever provides a way to specify that the value for the selected property should never be generated automtically by the database. ![]()
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