Problems verifying if an object exist on entity framework

[desanti]

Hello ! I'm using vb.net with EF 6 and sql server 2008R2. I have one table on database Myobject ( id , code , name) I want to add new records but verifying if an object with the same code exist. These records that have the same code are not added.

Dim mynewobject as Myobject
For I=1 to 100
newcode= InputBox("Input code", "Value")
newname= InputBox("Input Name", "Value")
if IsNothing(context.Myobjects.Where(Function(t1) t1.code=newcode).Firstordefault) then
mynewobject=New Myobject
mynewobject.code=newcode
mynewobject.name=newname
context.Myobjects.Add(mynewobject)
end if
Next
context.savechanges

Now let's suppose that i want to add these records :

Id Code Name
1 cd1 Name1
2 cd2 Name2
3 cd1 Name3

The third record should not be added because has the same code with the first record that has been added before. But when i execute my code , the third record is added too. What can i do ? Thank you !

[Richard Deeming]

Try:

If context.Myobjects.All(Function(t1) t1.code <> newcode) AndAlso context.Myobjects.Local.All(Function(t1) t.code <> newcode) Then

---

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

[Lost User]

desanti wrote:

What can i do ?

Add a constraint in SQL server to prevent it.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

[Mycroft Holmes]

Programming by error AAaaahhhhhhhhh. I agree that a constraint is valid but the problem is known in the business layer and should be trapped there, the DB constraint should only be insurance.

Never underestimate the power of human stupidity - RAH I'm old. I know stuff - JSOP

[Lost User]

Mycroft Holmes wrote:

Programming by error AAaaahhhhhhhhh.

Adding constraints is done to keep the data correct and consistent. It is not "programming by error", it is about preventing them.

Mycroft Holmes wrote:

I agree that a constraint is valid but the problem is known in the business layer and should be trapped there, the DB constraint should only be insurance.

There "should be" a decent database-design to begin with.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

[Mycroft Holmes]

Eddy Vluggen wrote:

It is not "programming by error", it is about preventing them.

Certainly this is true of a competent developer but I have seen may apps where they are trapping the error returned from the database and then dealing with the issue in the BL instead of dealing with the error before it hits the database.

Never underestimate the power of human stupidity - RAH I'm old. I know stuff - JSOP

[Lost User]

Mycroft Holmes wrote:

Certainly this is true of a competent developer but I have seen may apps where they are trapping the error returned from the database and then dealing with the issue in the BL instead of dealing with the error before it hits the database.

Aw, the horror. :rolleyes:

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^] "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.