I'm working on anASP.NET MVCproject, I useEntity
Framework[ Database First ], I created adata modeldepend
onSQL server database, I created a Table in the database and I updated the data model from the database, and when I try to add a record
to the new table I created (this table doesn't have a PK)I got an error,
when I search about the error I Understood that inEntity Framework need to have a PK for Entity.
So I ASK if I can set aPrimary Keyfor anEntitywithout affect database, or any other solution to solve this problem and massive thanks in advance.
Depends. Do you have already a column that could be used as a pk? If you meant you can't even add a primarty key constraint on the db side you can still lie to EF by using for example
https://www.learnentityframeworkcore.com/configuration/fluent-api/haskey-method to tell which column should be used as a pk. EF won't check the db site but know i can use this value to build UPDATE statements.
Else you may have to add a new column or fix the db side (seems best to have a properly designed db unless this is a shortcoming in a 3rd party database).
Note that the primary key is how you can uniquely identify a row so as soon as you want to update rows in a table it is likely that you do have a primary key in this table even if not explictly declared else you couldn't write an UPDATE query with a WHERE
clause that can change only the row you want.
You can add a primary key to an entity without affecting the database. Even if you set the primary key for the entity,
the error will still appear.
The Entity Framework can support table without primary key.By default, EF can only be updated if there is a primary key. But you can use
SqlQuery or
ExecuteSqlCommand to update.Please refer to Raw SQL Queriesfor detailed usage.
Although the above solution can meet your needs, but from a certain perspective, such a design is not very good.No primary key will hinder many functions in the future.If you can modify your database, it is best to set the primary key in the database.
Member
2 Points
10 Posts
Set a Primary Key for an Entity without affect database [ Entity Framework ] [ Database First ]
Jul 15, 2020 11:41 AM|MBARK|LINK
I'm working on an ASP.NET MVC project, I use Entity Framework [ Database First ], I created a
data modeldepend on SQL server database, I created a Table in the database and I updated the data model from the database, and when I try to add a record to the new table I created (this table doesn't have a PK) I got an error, when I search about the error I Understood that in Entity Framework need to have a PK for Entity.So I ASK if I can set a
Primary Keyfor anEntitywithout affect database, or any other solution to solve this problem and massive thanks in advance.All-Star
47420 Points
17545 Posts
Re: Set a Primary Key for an Entity without affect database [ Entity Framework ] [ Database First...
Jul 15, 2020 12:20 PM|PatriceSc|LINK
Hi,
Depends. Do you have already a column that could be used as a pk? If you meant you can't even add a primarty key constraint on the db side you can still lie to EF by using for example https://www.learnentityframeworkcore.com/configuration/fluent-api/haskey-method to tell which column should be used as a pk. EF won't check the db site but know i can use this value to build UPDATE statements.
Else you may have to add a new column or fix the db side (seems best to have a properly designed db unless this is a shortcoming in a 3rd party database).
Note that the primary key is how you can uniquely identify a row so as soon as you want to update rows in a table it is likely that you do have a primary key in this table even if not explictly declared else you couldn't write an UPDATE query with a WHERE clause that can change only the row you want.
Participant
930 Points
329 Posts
Re: Set a Primary Key for an Entity without affect database [ Entity Framework ] [ Database First...
Jul 16, 2020 07:29 AM|YihuiSun|LINK
Hi MBARK,
Best regards,
Yihui Sun