I have been working with MVC 4 and Entity Framework to create a web app recently. Things have been going well with my database "ppProject" model, as shown here:
Public Class ppProject
<Key()>
Public Property ProjectID As Integer
Public Property ClientID As Integer
Public Property ProjectTitle As String
Public Overridable Property Client As ppClient
Public Overridable Property Milestones As ICollection(Of ppMilestone)
Public Overridable Property Tasks As ICollection(Of ppTask)
End Class
The problem is that I am adding a new table of employees, "ppEmployees". This way the Project can have a ProjectManager, which is a foreign key into the Employees table. These are the new models where ProjectManagerID (foreign key) is linked to EmployeeID (primary key):
Public Class ppProject
<Key()>
Public Property ProjectID As Integer
Public Property ClientID As Integer
Public Property ProjectTitle As String
Public Property ProjectManagerID As Integer 'NEW'
Public Overridable Property Client As ppClient
Public Overridable Property Milestones As ICollection(Of ppMilestone)
Public Overridable Property Tasks As ICollection(Of ppTask)
Public Overridable Property ProjectManager As ppEmployee 'NEW'
End Class
Public Class ppEmployee
<Key()>
Public Property EmployeeID As Integer
Public Property DepartmentID As Integer
Public Property FirstName As String
Public Property LastName As String
Public Overridable Property ProjectsInManagement As ICollection(Of ppProject)
Public Overridable Property TimeItems As ICollection(Of ppTimeItem)
Public Overridable Property Department As ppDepartment
End Class
When I change my project model and add the employee model, I am getting the error
Invalid column name 'ProjectManager_EmployeeID'
The line of code that is triggering this is when I first access my projects in a view with:
#For Each proj In client.Projects
Any ideas at what is causing this? This must be a naming convention problem or something simple because I haven't had any errors with any of my other table models prior to this.
EDIT - See my answer below. Very confused about what Entity Framework is doing here.
In Entity Framework the name of the field must match the name of the column.
otherwise EF wouldnt know how to map the fields unless you decorate the property with the column attribute like you did in your answer.
Ok I think I've fixed this. I had to make the following changes to the "ppProject" class:
<Column("ProjectManagerID")>
Public Property EmployeeID As Nullable(Of Integer) 'Has to be set, dont know why
If anyone knows why my property has to be named EmployeeID, please let me know. I'm very curious.
I had a similar problem about a month ago. I dropped the table and created a new one and the problem was solved. that is after i have tried other ways that did not work
Related
I'm trying to migrate an objectcontext/edmx system to dbcontext (EF6) with fluent mapping. I have a few instances like the following. Principal table has a relationship to a dependent table where a non-PK column in the dependent table holds the value of a PK column in the principal. On its own this would be a one to many relationship, but there is a unique index on the dependent table FK columns. Using EDMX mapping, this works fine as long as you define the relationship using mapping rather then referential constraints. Below is an executable example - you don't need the database because it doesn't get that far, currently:
Imports System.Data.Entity
Imports System.Data.Entity.ModelConfiguration
Module Module1
Sub Main()
Using session As New SaturnEntities
Dim res = session.BookingLegSet.Select(Function(x) New With {x.Prefix, x.ID, x.AddressDetails.Address}).ToList
End Using
End Sub
End Module
Partial Public Class BookingLeg
Public Property Prefix As String
Public Property ID As Integer
Public Property LegIndex As Integer
Public Overridable Property AddressDetails As BookingLegAddress
End Class
Partial Public Class BookingLegAddress
Public Property Prefix As String
Public Property ID As Integer
Public Property Address As String
Public Overridable Property BookingLeg As BookingLeg
Property JobLegPrefix As String
Property JobLegID As Integer?
End Class
Public Class BookingLegConfig
Inherits EntityTypeConfiguration(Of BookingLeg)
Public Sub New()
ToTable("JobLegs", "dbo")
HasKey(Function(x) New With {x.Prefix, x.ID})
HasOptional(Function(x) x.AddressDetails).WithRequired(Function(x) x.BookingLeg).Map(Function(x) x.MapKey("Prefix", "ID"))
End Sub
End Class
Public Class BookingLegAddressConfig
Inherits EntityTypeConfiguration(Of BookingLegAddress)
Public Sub New()
ToTable("JobAddresses", "dbo")
HasKey(Function(x) New With {x.Prefix, x.ID})
HasRequired(Function(x) x.BookingLeg).WithOptional(Function(x) x.AddressDetails).Map(Function(x) x.MapKey("JobLegPrefix", "JobLegID"))
End Sub
End Class
Partial Public Class SaturnEntities
Inherits DbContext
Public Sub New()
MyBase.New("data source=dbSaturn;initial catalog=Saturn;integrated security=True;MultipleActiveResultSets=True;")
End Sub
Protected Overrides Sub OnModelCreating(modelBuilder As DbModelBuilder)
modelBuilder.Configurations.Add(New BookingLegConfig)
modelBuilder.Configurations.Add(New BookingLegAddressConfig)
End Sub
Public Overridable Property BookingLegAddressSet() As DbSet(Of BookingLegAddress)
Public Overridable Property BookingLegSet() As DbSet(Of BookingLeg)
End Class
BookingLeg is the principal entity and BookingLegAddress is the dependant. JobLegPrefix and JobLegID in the dependent will be either null or will hold the Prefix and ID values from a BookingLeg record. When you run this you get an error that AddressDetails has been configured with conflicting mapping information. I've tried numerous different ways to map this, but haven't got anywhere - can anyone tell me what I need to do?
Remove the
HasOptional(Function(x) x.AddressDetails).WithRequired(Function(x) x.BookingLeg).Map(Function(x) x.MapKey("Prefix", "ID"))
line from BookingLegConfig class. Every single relationships must be configured only once in a single place (part of the configuration of any of the two involved entities, but not in both). In this particular case you should keep the second configuration inside BookingLegAddressConfig class
HasRequired(Function(x) x.BookingLeg).WithOptional(Function(x) x.AddressDetails).Map(Function(x) x.MapKey("JobLegPrefix", "JobLegID"))
because it specifies the correct FK column names.
Also EF6 does not support explicit FK columns for this type of relationship - no HasForeignKey fluent API, and MapKey is for specifying shadow property (and column) names. So additionally remove the JobLegPrefix and JobLegID properties from the BookingLegAddress class:
Partial Public Class BookingLegAddress
Public Property Prefix As String
Public Property ID As Integer
Public Property Address As String
Public Overridable Property BookingLeg As BookingLeg
End Class
I am complete beginner with ASP.net and VB.net, I created two classes one for Teams and another for Fixtures which will take in 2 teams.
Imports System.Data.Entity
Public Class Team
Public Property ID() As Integer
Public Property Name() As String
Public Property Points() As Integer
End Class
Public Class TeamDBContext
Inherits DbContext
Public Property Teams() As DbSet(Of Team)
End Class
Imports System.Data.Entity
Public Class Fixture
Public Property ID() As Integer
Public Property Week() As Integer
Public Property HomeTeam() As Team
Public Property AwayTeam() As Team
End Class
Public Class FixtureDBContext
Inherits DbContext
Public Property Fixtures() As DbSet(Of Fixture)
End Class
I created a FixturesController with the read/write actions and views. However when I go to create a Fixture in my application I only see a field for Week and not field for HomeTeam or AwayTeam.
Well you need to add them manually. Brad Wilson wrote a nice article explaining in details how you could make the templated helpers to recursively descend in your nested models.
Also as a side remark you probably don't need 2 db contexts, one should be enough and it could contain both your Teams and Fixtures:
Public Class FixtureDBContext
Inherits DbContext
Public Property Teams() As DbSet(Of Team)
Public Property Fixtures() As DbSet(Of Fixture)
End Class
I'm new to ASP.NET MVC, altough could call myself experinced programmer in web forms field.
I'm learning MVC now. Trying to add controller with Entity framework abolities.
Here is below code of model class:
Imports System.Data.Entity
Public Class Users
Public Property ID() As Integer
Public Property Login() As String
Public Property Password() As String
Public Property Avatar() As Image
Public Property Country() As Integer
Public Property City() As Integer
Public Property Phone() As String
Public Property Email() As String
Public Property Registered() As Date
End Class
Public Class StopSaleDBContext
Inherits DbContext
Public Property Users() As DbSet(Of Users)
End Class
When I'm adding controller I got error Unable retrieve metadata from ProjectName.Users Object reference not set to an instance of object.
Compile your project and try again.
Here are the entities that i have...
Public Class Account
Public Property AccountId As integer
Public Property AccountDescription As String
Public Property Transactions As List(Of Transaction)
End Class
Public Class Transaction
Public Property TransactionId As Integer
Public Property AccountId As Integer
Public Property TransactionDescription As String
End Class
i would like to make it suc that when i do "db.Account.find(1)" for example it also loads in the list of all transactions which have the coresponding AccountId. I'm not too sure what type of relationship this is?? anyway, right now i can do
Dim acct As Account = db.Account.Find(1)
acct.Transactions = from ts in db.transactions select ts where ts.AccountId = acct.accountid
but i know this is not the correct way, there must be a way to map this out so that entity can just load everything in one shot right? Thanks for any help.
You can use db.Account.Include("Transactions").SingleOrDefault(1) or put Transactions as virtual (I think it is Overridable in vb).
I've got a number of classes which have a relationship to other classes for properties like Location, Currency etc. Take the following example:
Public Class Transaction
Public Property ID As Integer
Public Property Description As String
Public Property Quantity As Integer
Public Property SaleAmount As Double
Public Overridable Property Currency As Currency
End Class
Public Class Currency
Public Property ID As String
Public Property Description As String
Public Property Symbol As String
Public Property SymbolImage As String
End Class
I add my currencies when I initialise the application for first use. When adding a transaction, I have a drop down box to select the currency.
I have no issues saving the Transaction to the db and the currency ID is saved also.
When I edit the transaction and try to change the currency, I can't get it to save back to the db.
<HttpPost()>
Function Edit(transaction As Transaction) As ActionResult
transaction.Currency = db.Currencies.Find(transaction.Currency.ID)
Debug.Print("Currency: " & transaction.Currency.ID)
If ModelState.IsValid Then
db.Entry(transaction).State = EntityState.Modified
db.SaveChanges()
Return RedirectToAction("Index")
End If
Return View(transaction)
End Function
When I do the debug.print in the post method above, the currency is correctly being reported as the changed currency but the Currency ID on the Transaction record in the DB isn't updated.
I've done some searching and reading and haven't found much/anything.
I did try adding this line to the post method but it still didn't save the changes:
db.Entry(transaction.Currency).State = EntityState.Modified
I'm stumped and would appreciate any help!
So here's the best solution I could find. I'd be interested to hear other ways to achieve the same result. The other methods I've found are much more complicated than this.
Public Class Transaction
Public Property ID As Integer
Public Property Description As String
Public Property Quantity As Integer
Public Property SaleAmount As Double
Public Property Name As String
Public Property CurrencyID() As String
<ForeignKey("CurrencyID")>
Public Overridable Property Currency() As Currency
End Class
I've setup the Edit view with a drop down list containing a list of the currencies and a hidden field to store the CurrencyID. The edit post looks like this:
<HttpPost()>
Function Edit(transaction As Transaction) As ActionResult
If ModelState.IsValid Then
db.Entry(transaction).State = EntityState.Modified
db.SaveChanges()
Return RedirectToAction("Index")
End If
Return View(transaction)
End Function