Convert (1 to Many ) to (1 to 1) Case

Hi, here is my case,

I have two tables:

1- Employee (ID, Number, Salary) ID is a primary identity key.

2 -Language (ID,Name) ID is a primary identity key.

2- EmployeeTranslation (EmployeeID, LanguageID, Name) EmployeeID + LanguageID is a primary key, and EmployeeID is foreign key

constraint to the Employee table for the ID column, and the LanguageID is foreign key constraint to the Language table for the ID

column.

So these tables enables you to insert an employee row with multi translations rows (His name in english, french, japanese .. etc) .

When i map this to the entity framework using database first model i will get an Employee entity with a relation to a many translation

entities of type EmployeeTranslation (1 to Many), but what i really want is to map the Employee entity to one EmployeeTranslation

entity (1 to 1), why,because the real business senario here is that i will only and always get an Employee Entity with one Translation

Entity based on the system current language, How can i apply this in entity framework.

Note: When you convert the (1 to Many) relation in this senario to (1 to 1) you will get and error of course.

Re: Convert (1 to Many ) to (1 to 1) Case

If an Employee can only have one EmployeeTranslation and an EmployeTransaction only belongs to one Employee, you should remove the EmpoyeeTranslation table in your database and add the columns LanguageID and [Translation]Name to the Employee table. Then you will get a 1-to-1 relationsship. There is no need to have another table for that.

Re: Convert (1 to Many ) to (1 to 1) Case

The employee can have more than one translation in the data base tables but in the Domain layer (Business layer) i should get one

for the current system language.

Re: Convert (1 to Many ) to (1 to 1) Case

If you for some reason wants to keep the EmployeeTranslation table, you should set the EmployeeID column as primary key and remove the foreign key between the Employee and EmployeeTranslation table.

Re: Convert (1 to Many ) to (1 to 1) Case

matelin

The employee can have more than one translation in the data base tables but in the Domain layer (Business layer) i should get one

for the current system language.

If you don't want your domain model to behave like your database model you can't excpect the database-first generated model to work without any modifications to it. Please see this article for an example of how to define a 1-to-1 relationsship in code: http://blog.bennymichielsen.be/2011/06/02/entity-framework-4-1-one-to-one-mapping/

Re: Convert (1 to Many ) to (1 to 1) Case

mm10

If you for some reason wants to keep the EmployeeTranslation table, you should set the EmployeeID column as primary key and remove the foreign key between the Employee and EmployeeTranslation table.

I think this will road to an inconsistent mapping by removing the relation and an unwell designed relational database.

Any other ideas.

Re: Convert (1 to Many ) to (1 to 1) Case

matelin

I think this will road to an inconsistent mapping by removing the relation and an unwell designed relational database.

Yes, if the tables in your DB are to have a 1-to-many relationsship you cannot to this but if the relationsship is 1-to-1 you should do this.

Re: Convert (1 to Many ) to (1 to 1) Case

One of the reasons for what i want is that i already have a custom entity mapping implementation for that , but i want to implement

this using entity framework so i can benefits from its features.

And yes i know it will require an extra work ,for that iam asking for help,i will read more about code first model , i may have it done,

i know a little about code first model ,but what iam afraid of the code first nodel is to lose the control over my database.

Any help will be appreciated

Re: Convert (1 to Many ) to (1 to 1) Case

Hello matelin

As far as I seeI think since you want to make Employee(One)(One)EmployTranslationIn fact I think you can find a certain Employee to find out what language he/she is speaking nowSo there's no need for you to create EmployeeTranslationBut just do this

Solutions

Employee(Id,Number,Salary,LanguageId)Here LanguageId is a foreign key mapped to Language table

Language(Id,LanguageName)Id the primary key

Shorten the three tables into two

Re: Convert (1 to Many ) to (1 to 1) Case

I can not do that, becuase the idea behind that is to allow the user to translate the text data like employee name to many laguages.

Re: Convert (1 to Many ) to (1 to 1) Case

matelin
becuase the idea behind that is to allow the user to translate the text data like employee name to many laguages.

Solutions

Employee(Id,Name,Salary)Here only for Employees

Language(Id,LanguageName)Here's only for Languages

Translations(Id,EmployeeId,LauguageId)Here's a joint table for Employee and LanguageIn my mindYou should create a Many-To-Many relationship between the two tablesbecause One Employee can have multiple languagesand so you can find out all the languages belonging to a certain EmployeeAnd if one employee can only learn one languageyou can find only onefor "One" is a special thing for Many

Reguards