Say I have the following table definitions in SQL Server 2008:
CREATE TABLE Person
(PersonId INT IDENTITY NOT NULL PRIMARY KEY,
Name VARCHAR(50) NOT NULL,
ManyMoreIrrelevantColumns VARCHAR(MAX) NOT NULL)
CREATE TABLE Model
(ModelId INT IDENTITY NOT NULL PRIMARY KEY,
ModelName VARCHAR(50) NOT NULL,
Description VARCHAR(200) NULL)
CREATE TABLE ModelScore
(ModelId INT NOT NULL REFERENCES Model (ModelId),
Score INT NOT NULL,
Definition VARCHAR(100) NULL,
PRIMARY KEY (ModelId, Score))
CREATE TABLE PersonModelScore
(PersonId INT NOT NULL REFERENCES Person (PersonId),
ModelId INT NOT NULL,
Score INT NOT NULL,
PRIMARY KEY (PersonId, ModelId),
FOREIGN KEY (ModelId, Score) REFERENCES ModelScore (ModelId, Score))
The idea here is that each Person may have only one ModelScore per Model, but each Person may have a score for any number of defined Models. As far as I can tell, this SQL should enforce these constraints naturally. The ModelScore has a particular "meaning," which is contained in the Definition. Nothing earth-shattering there.
Now, I try translating this into Entity Framework using the designer. After updating the model from the database and doing some editing, I have a Person object, a Model object, and a ModelScore object. PersonModelScore, being a join table, is not an object but rather is included as an association with some other name (let's say ModelScorePersonAssociation). The mapping details for the association are as follows:
- Association
- Maps to PersonModelScore
- ModelScore
ModelId : Int32 <=> ModelId : int
Score : Int32 <=> Score : int
- Person
PersonId : Int32 <=> PersonId : int
On the right-hand side, the ModelId and PersonId values have primary key symbols, but the Score value does not.
Upon compilation, I get:
Error 3002: Problem in Mapping Fragment starting at line 5190: Potential runtime violation of table PersonModelScore's keys (PersonModelScore.ModelId, PersonModelScore.PersonId): Columns (PersonModelScore.PersonId, PersonModelScore.ModelId) are mapped to EntitySet ModelScorePersonAssociation's properties (ModelScorePersonAssociation.Person.PersonId, ModelScorePersonAssociation.ModelScore.ModelId) on the conceptual side but they do not form the EntitySet's key properties (ModelScorePersonAssociation.ModelScore.ModelId, ModelScorePersonAssociation.ModelScore.Score, ModelScorePersonAssociation.Person.PersonId).
What have I done wrong in the designer or otherwise, and how can I fix the error?
Many thanks!
Very late to your question, I had the same issue and discovered that the entity framework designer had identified my "ScoreId" column (relative to your PersonModelScore table) as a primary key column. I changed my setting to false for my ScoreId, and all worked well afterward.
You can set single primary key in the Entity in order to avoid this error.Right Click on the Scalar Properties of the field in the Entity and disable Entity Key if there are many primary keys.
You should create a single Identity key for each table.
ModelScore should have a ModelScoreId, PersonModelScore should have a PersonModelScoreId.
References between table should be a single field.
Your PersonModelScore table should define an Id column that is identity and primary key, then
you should create a unique key on PersonId, ModelId
as for Error 3002, i had the same problem ALL my field had been marked Entity key by EF
"Go to your .edmx file, right click on the background and select 'Mapping Details'. Click on the Table you need to edit the mappings of in your .edmx window and the details should appear in your new 'Mapping Details' window. Open Properties tab (Hit F4 to bring up the 'Properties' if not open) Click on the 'Value/Property' in your 'Mapping Details' to change the Properties displayed, and from your Properties window you can now set the 'Entity Key' value to 'False'. – Chris Paton Oct 4 '14 at 18:54"
This worked for me - Thanks
This is now part of my workflow when using EF Database First. And we have a task out to update the data model.
Related
We have an existing database which we'd like to connect to using code-first EF.
An issue we have come across is in the following scenario...
**TABLE 1**
DebtorID Int PK (identity column)
Type Int PK FK ( value would be '1' - FK to Table 4)
**TABLE 2**
CreditorID Int PK (identity column)
Type Int PK FK (value would be '2' - FK to Table 4)
**TABLE 3**
TransactionID Int PK
ParentID Int FK
ParentType Int FK
-----------------------
**TABLE 4**
Type Int PK (identity column)
Description Varchar(max)
Table 3 has foreign key links to multiple tables (Table 1, Table 2, etc...). The key is unique by the type column. Constraints have been altered here to allow this scenario.
Q. How can we implement this schema using code-first? We have looked at Data Annotations, and also Fluent API, but can't come up with a solution other than to alter the database schema (which would be a big headache).
As it stands, we only seem to be able to link to a single foreign table.
The solution also has to account for other tables (not shown here) where the primary keys for Table 1 etc... are part of the primary key.
A real world view of our schema, and the issue with code-first.
Current schema:
http://oi60.tinypic.com/2aeug4m.jpg
Code-First schema:
http://oi62.tinypic.com/9schmc.jpg
I have found the answer using the Fluent Api - was much easier than I thought.
Simply in the OnModelCreating() method, I needed to add multiple ForeignKey entries to cover each link.
modelBuilder.Entity(Of TABLE_3).HasRequired(Function(p) p.TABLE_1).WithMany().HasForeignKey(Function(p) New With {p.ParentID, p.ParentType})
modelBuilder.Entity(Of TABLE_3).HasRequired(Function(p) p.TABLE_2).WithMany().HasForeignKey(Function(p) New With {p.ParentID, p.ParentType})
This was in addition to any configuration I did using Data Annotation with regards to setting up primary keys and navigational properties (e.g. navigation properties for TABLE_1 and TABLE_2)
This is a simplified version of the problem I'm facing. Basically, I have an existing database with code-first Entity Framework on top of, and there are several tables where I see an ObjectId and ObjectType field. Depending on the ObjectType, the table can be joined to one of several other disparate tables which do not share a hierarchy.
For example, given the following database tables:
CREATE TABLE BarCode
(
Id int NOT NULL PRIMARY KEY,
ObjectType int NOT NULL,
ObjectId int NOT NULL,
BarCodeValue varchar(20) NOT NULL,
)
CREATE TABLE Person
(
Id int NOT NULL PRIMARY KEY,
Name varchar(20),
)
CREATE TABLE Package
(
Id int NOT NULL PRIMARY KEY,
Name varchar(20),
)
I might see rows in the BarCode table with an ObjectType of 1, which correspond to Person records, or rows with an ObjectType of 2, which correspond to Package records.
In Entity Framework, how do I set up a mapping so that the Person entity can have a BarCode and the Package entity can have a Barcode? I don't see where the Map() method allows you to specify any fields other than the foreign key field. Like I said, there's really no hierarchy among these objects, it's more that they share a common attribute. Sort of like decorating a class with an interface vs. having it inherit from something.
I have a WCF Data Service (5.5) sitting over an EF (5.0) model,
I'm getting the following error when I query $metadata:
"An IEdmModel instance was found that failed validation. The following errors were reported:
InvalidMultiplicityOfDependentEnd : The multiplicity of the dependent end 'QuestionsetMember' is not valid. Because the dependent properties don't represent the dependent end key, the the multiplicity of the dependent end must be '*'."
QuestionsetMember has a composite primary key of 2 columns, each of which is hooked to a primary key of another table, i.e. a foreign key exist from each column of the key to the two tables' primary keys.
I've searched but cannot find any info on "InvalidMultiplicityOfDependentEnd".
Also tried fiddling with the relationships in the EDMX, but changing the End Multiplicity causes errors which won't allow the model to compile.
Any ideas how to get round this (hopefully without changing my schema) ?
This seems to be a very rare error. I did not find anywhere else an explanation of that error. So i did find for me a solution after inspecting every single constraint and every column in both tables. To my great surprise the order of the primary key columns seems to be relevant.
For explanation: I do the database-design within the sql server management studion, and update my model with the entity framework designer.
First Table:
CREATE TABLE Table1
(
Column1 int NOT NULL,
Column2 int NOT NULL,
PRIMARY KEY (Column1,Column2)
)
Second Table:
CREATE TABLE Table2
(
Column1 int NOT NULL,
Column2 int NOT NULL,
PRIMARY KEY (Column1,Column2)
FOREIGN KEY (Column1,Column2) REFERENCES Table1(Column1,Column2)
)
This would work. But it do not work, if you would define the columns of the primary key in the second table in another order:
CREATE TABLE Table2
(
-- Changed order in definition:
Column1 int NOT NULL,
Column2 int NOT NULL,
-- Changed order in PK group:
PRIMARY KEY (Column2,Column1)
-- Leave the FK definition untouched:
FOREIGN KEY (Column1,Column2) REFERENCES Table1(Column1,Column2)
)
I think the order of the column definition has impact on the generated model. And this order could maybe have an impact in the model validation within the IEdmModel class. Who knows...
In EF Code First, we can create one-to-one relationship by coding like this:
public class User
{
public int UserID {get;set;}
public string Name {get;set;}
public int UserDetailID {get;set;}
public UserDetail Detail {get;set;}
}
public class UserDetail
{
public int UserDetailID {get;set;}
public string Address {get;set:}
public int UserID {get;set;}
public User User {get;set;}
}
However, when I tried to create the same relationship by using EF Database first in visual studio 2012, I got in trouble. Here is my code:
CREATE TABLE [dbo].[Users] (
[UserID] UNIQUEIDENTIFIER CONSTRAINT [DF_Users_UserID] DEFAULT (newid()) NOT NULL,
[UserDetailID] UNIQUEIDENTIFIER NOT NULL,
[Name] NVARCHAR (50) NOT NULL,
CONSTRAINT [PK_Users] PRIMARY KEY CLUSTERED ([UserID] ASC),
CONSTRAINT [FK_Users_UserDetails] FOREIGN KEY ([UserDetailID]) REFERENCES [UserDetails]([UserDetailID])
);
CREATE TABLE [dbo].UserDetails] (
[UserDetailID] UNIQUEIDENTIFIER CONSTRAINT [DF_UserDetails_UserDetailID] DEFAULT (newid()) NOT NULL,
[UserID] UNIQUEIDENTIFIER NOT NULL,
[Address] NVARCHAR(100) NOT NULL,
CONSTRAINT [PK_UserDetails] PRIMARY KEY CLUSTERED ([UserDetailID] ASC),
CONSTRAINT [FK_UserDetails_Users] FOREIGN KEY ([UserID]) REFERENCES [dbo].[Users] ([UserID])
The error message is something like
"Error 2 SQL01767: Foreign key 'FK_Users_UserDetails' references invalid table 'UserDetails'.
I think the reason for this error probably be when it tries to reference the foreign key "UserDetailID", it finds that it hasn't been created yet. But I don't know how to fix this, and I don't even know this is the way to do it, I know doing one-to-one relationship with EF is tricky, or some people even says it's impossible. Can anyone give me any suggestion? Thank you.
Update: Just to clarify my case, I am trying to design the database in visual studio 2012 database project, then publish it to the SQL server, afterward, create/update my .edmx file from the database in SQL server. I am not sure about how to create a one-to-one relationship that the EF can recognize correctly and create the right classes in .edmx file.
Creating a 1:1 relationship is not that tricky and certainly not impossible, although it is not a particularly common requirement and in this case I can't see why you would want it? If people are saying this then you are talking to the wrong people.
Anyhow using SQL queries as you seem to be is not to do with EF, you are just working directly with the database, In the first CREATE you are trying to add the constraint but you haven't created the other table yet... As you mentioned in your question.
I think you need to create both tables first and then add the constraint with ALTER TABLE.
Additionally searching SO for questions about 1:1 turns up quite a lot so I suggest you do that.
EDIT: So using a database project (I only have VS Express so I don't have those) you want to create a "1:1" relationship using SQL and then add an Entity Data Model to a (probably different) project which references the database and automatically create 1:1 relationship?
That is a whole different story unfortunately. When I was talking about possibility to create 1:1 that was in reference to EF only and not to databases as such. It is actually very difficult/impossible as you said to create 1:1 in SQL. I think that it makes sense that in order to insert into a 1:1 realationship you would need to somehow insert into both tables at exactly the same time or fiddle about with disabling constraints briefly when adding rows.
In general there are a few different option.
Don't split the tables unnecessarily. In true 1:1 all data is required so the only reason to split is for performance reasons (e.g partioning) which I would avoid in this case.
Map multiple table to a single entity as show here.
Create a 1:0..1 relationship and enforce you own requirements in the application.
In either option 2 or 3 you can use the following SQL to create a relationship which uses the same PK on the second table as the FK in the relationship.
CREATE TABLE [dbo].[Users] (
[UserID] UNIQUEIDENTIFIER CONSTRAINT [DF_Users_UserID] DEFAULT (newid()) NOT NULL,
[Name] NVARCHAR (50) NOT NULL,
CONSTRAINT [PK_Users] PRIMARY KEY CLUSTERED ([UserID] ASC),
);
CREATE TABLE [dbo].[UserDetails] (
[UserID] UNIQUEIDENTIFIER NOT NULL,
[Address] NVARCHAR(100) NOT NULL,
CONSTRAINT [PK_UserDetails] PRIMARY KEY CLUSTERED ([UserID] ASC),
CONSTRAINT [FK_UserDetails_Users] FOREIGN KEY ([UserID]) REFERENCES [dbo].[Users] ([UserID]) ON DELETE CASCADE
);
I suggest you also use store generated identity as well where you can.
Just remove UserDetailID from the UserDetail table and make UserID both primary key and a foreign key to the UserID column of the User table.
This the correct way to make 1:1 relationships in a database and EF recognizes it and maps the entities appropriately with database-first approach.
The question is a couple years old.. and the ef version wasn't stated.. but one answer is to remove UserDetailID from both tables. UserID should be the only primary key on both tables.
the 'unqieidentifier' (GUID) data type shouldn't pose an issue (opposed to using INT), but you certainly don't want to populate it with newId..
If I have 2 tables 1 with a composite primary key where one of the keys is also a foreign key in another table:
Table 1:
A (PK, FK - maps to X in Table 2)
B (PK)
C
Table 2:
X (PK)
Y
Because A is both the PK in table 1 and FK in table 2, when I use EF to generate the entity model, I have both a Scalar AND a Navigation property for A in table 1. I cannot seem to remove A as a scalar (I think because it is a primary key).
The problem I am having is that if I create a table1Entity and set A's scalar property to a new value, A's navigation property will not be changed automatically (and vice versa).
Ideally I just want A to expose the navigation property - which is the way it behaves if A was not also part of the composite primary key anyway. Is there any way to achieve this?
Am I correct in assuming that Table1 derives from Table2? If so, I would do it like so:
(I'd also change the PK for both tables to the same name, since they probably have the same meaning - for the instance of this, I'll use the example ID)
First, create the model with the default relationships (I usually just import the two tables from the database)
In the designer, right click the base type, add inheritance, select the derived type.
Delete the one to zero or one association
Then, since the base type already has column ID, delete it from the derived type.
Go to table mapping for the derived type, and map the ID property to the ID of the table.
Well, not really. Create the view with schemabinding and create a clustered index on the view (SQL Server 2008 or later, earlier versions I'm not sure can do that). The clustered index will be recognised as a primary key, thus tricking EF(VS) into believing the view is a real table.
Have you expicity set the Ids of the composite key and referenced these in your configuration?
i.e
public class Table1
{
public Table2 A{get;set}
public int AId {get;set;}
public int BId {get;set;}
}
I assume you'll need something like:
HasKey(pc => new { pc.AId, pc.BId});
HasRequired(x => x.A).WithMany().HasForeignKey(x => x.AId);
Instead of mapping to table 1 directly, add a view to your database that's got all of table 1's fields, plus an extra copy of A (A2).
Then, map the scalar key to A2 and the nav key to A.
(You'll run into a problem where if you use a view, Visual Studio can't find a primary key; fix this by manually editing the XML of the edmx file and adding a <Key><PropertyRef ... /></Key> to the <EntityType> for table A)
I know - it's hacky and horrible... but hey - it works!