实体框架：如何在数据库中的同一表的模型中具有多个实体？

Question

I'm new to entity framework and I've read entity framework documentation and It had talk about Conceptual Model and Logical Model .

I was thinking if entities in my model should match with database tables? I guess the answer is no. But I want to know how can I Implement below scenario:

I want to have an entity for updating of a table and have another one for reading from that table. Eg I want to have an entity called EditStudent and other one named ViewStudent with different fields brought from table Student in my database.

And then when I update EditStudent field I can submit changes to those field on Student table.

How is it possible? And besides, is my scenario is a usual practice in Entity Framework or it is common to have one entity per database table?

Answer 1

Usually when handling databases there are several levels of abstraction.

When using Entity Framework you'll quite often the the Repository Pattern . If you google it you'll find numerous explanations.

You'll find two layers (not sure if the names of the layers are the used everywhere)

• The database layer. This represents the tables in your database and the relationships between the tables. In Entity Framework this is your DbContext, with its DbSets. Every DbSet is a table, holding the columns and constraints on the columns. The model stored in the DbContext represents the relations between the tables: one-to-many, many-to-many, which keys are used as foreign keys etc.
• The repository layer represents the actions you'd want to do on the database layer. It hides what database method you are using. Users of your repository layer shouldn't know whether this layer uses entity framework or another method to access the database. In fact it doesn't have to be a database; for a user of the repository layer the data could be an excel spreadsheet file.

If you follow this division, your DbContext should represent your database. The way you plan to use this database is not in your DbContext.

The notion of an editable student and a vieuwable student are typically things from your repository layer. They will both access the Student table in your DbContext, but one type will probably only return interfaces with public get functions, while the other type will have functionality to change the data of the Student. Both will use the same table in the same DbContext.