Generate A Entity Model From SQL Server?
Feb 6, 2012
I am using MS Visual Basic Express 2010 and trying to generate "ADO.Net Entity Framework" entities from an existing local SQL Server Express database.
Using the "Entity Data Model Wizard" I am asked to configure a connection. Here I prompted to choose a "Data source" and given two options 'Microsoft SQL Server Compact 3.5' and 'Microsoft SQL Server Database File'. I select the second option.
I'm then prompted for connection properties, I have to enter the "Database file name (new or existing)". Here I browse to the SQL server database file of interest (found using Management Studio Express) namely[code]...
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Dec 1, 2011
I have a misunderstanding somewhere with the Entity Framework. This code is from my unit testing:
Public Sub UpdateRosterLinkTest()
Dim target As PlayerAdmin = New PlayerAdmin()
target.PlayerAdminManager = playerAdminTestManager
target.Team = playerAdminTestManager.GetAirForceMensBB()
[code]....
When I run this code, I can see the changes saved to the SQL Server this pulls from (RosterLink = Roster Link, like I set in the unit test).However, my unit test is failing, because team.RosterLink is still Nothing. The function GetAirForceMensBB() returns the Team with TeamId = 12434:
Function GetAirForceMensBB() As DAL.Team
Return (From team In Container.Teams Where team.TeamId = 12434).SingleOrDefault
End Function
I'm sure I'm using the entity framework incorrectly and it probably has something to do with the fact that I am calling the PlayerAdminTestManager in different places, but I don't understand why. Although, I set the PlayerAdminManager to be the PlayerAdminTestManager. PlayerAdminTestManager extends PlayerAdminManager, fyi.Why is team.RosterLink not showing the update from UpdateRosterLink?
EDIT:Container is my ObjectContext. This is how I access the information stored in the database.Container.Teams represents my Teams table.
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Jul 13, 2010
Whilst going through the "ADO.Net Entity Data Model" wizard, I select 3 tables from within a Database to add to my edmx file, and when the file is generated only one of the three tables is there. There was no error or warning to explain why the other tables haven't been added. If I try and add one of the failing tables on its own, again, nothing happens.I am using VS 2010, SQL Server 2008.
Any ideas as to why these database tables are failing to create? I realise there isn't much detail to this question, but there isn't much detail to the situation - It really is a database with 3 tables, of which 2 are failing to create through the wizard with no error.
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May 1, 2012
We need to store a list of data we pull from another table that relates to one of our models. (We are too deep into build to add this relationship to our DB where it should be.) When we attempt to load this list in a property of the model that needs it.We load this list into a dropdown in a view. The error occurs trying to load this list into the model in the controller. The true caveat is that we have a unique dropdown list for each record in our table in the view.
Our Class:
Public class OurModel
public property ID As Integer[code]....
Error: LINQ to Entities does not recognize the method 'DB.ModelTable get_Item(Int32)' method, and this method cannot be translated into a store expression.
UPDATE: The issue appears to be that LINQ is trying to do something with a the DBContext of a query I do previously in this controller. The error is referencing DB.Employee not DB.Position which is what I am querying.
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Apr 6, 2011
I have two properties ("FIRST_NAME" and "LAST_NAME") I need to access as a single property (e.g. "FULL_NAME"). Is there a way for me to add a property to my entity model that contains the combine value of FIRST_NAME and LAST_NAME?
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Mar 30, 2010
I'm pretty new to the EDM, so bear with me. I have a windows form that has a DataGridView on it that's bound from the EDM I created. I figured out how to update my changes fine, but it's when the user creates a new row that I'm having a problem.I tried numerous ways and many google searches, but came up with nothing so far.
[Code]...
Error (occurs when calling _Context.SaveChanges()): Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.
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May 6, 2010
in a new project I thought I would try to integrate the new Entity Model Framework, but am having some issues/problems and would like to know if there is a solution or workaround that will let me insert a record into a table that has an identity property.At first I thougth it might simply recofnize the storedprocs that I have for insert/update/delte actions, and was a bit discapointed when generating the model ignored all my stored procs. So I thought wll heck maybe it just generates a nice insert method for me. Lets see.So I referenced my model and found that for the table (entity) there was an insert action (method) that had been generated, however what i found is that it explicitly added the primarly key field - which was based on an identity property and will not accept an explicit insert value.So I guess 2 questions
1. How do we work with identity properties
2. How can we take advantage of the performance and securtiy advantages that stored procs offer with SQL server?
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May 22, 2012
I am working on a silverlight project in which i am using the entity data model. I have a consol application in the same solution through which i am creating the database table at runtime. Now when i moves to silverlight page i need to Communicate (load
data from newly created tables).But problem is that without updating the model how i will able to communicate with that table at runtime using entity framework model.
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Jun 9, 2012
In entity framework we can use 3 approaches model first , code first , database first but each one of them needs manual hand touch(means creating database or create model or write the POCO class codes or entity class codes) before proceeding to the next step ( using EF in context ).What if I want to create database and tables and table relationships programatically and still want to have to features of EntityFramework 4.3.
To be more specific ,from this example http://support.microsoft.com/kb/307283 we can create database , tables and everything using SQL command but we can't have the advantages of entity framework. So if we want to have that what should we do? To give the ability to create dynamic table fields those steps will not be sufficient. In all 3 steps database , table and table columns are fixed. There is no way that a user can create new tables or columns dynamically. http:[url].... in this post , it shows how to create manual db, tables and etc using SQL but it is based on ADO.NET but I want Entity Manager to do that.
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May 7, 2011
What is the best way to manually generate Primary Keys in Entity Framework 4.1 Code First?
I am programming ASP.NET MVC 3 and I use a repository pattern.
I currently generate keys in a sequential order by using the [code]....
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Aug 9, 2010
I want to have a single table that represents a person and have a number of other tables (such as Student/Teacher) use the Person table to store information related to a person. Unfortunately the entity framework doesn't seem to like it when I try to add an association between the Student or Teacher class and I don't understand why. The Person table contains a column called ParentEntityID, which equals either a StudentEntityID or a TeacherEntityID. In an ideal world I would like to be able to reference the Person table by going Student.Person.FirstName instead of Student.Entity.Person1.FirstName. The error .Net returns when trying to connect the Student/Teacher table to the Person table is:
Error 3007: Problem in Mapping Fragments starting at lines 265, 289: Non-Primary-Key column(s) [ParentEntityID] are being mapped in both fragments to different conceptual side properties - data inconsistency is possible because the corresponding conceptual side properties can be independently modified.
The actual database I am working with is a bit more complicated and has a number of tables connected to the Entity table, which makes my object model pretty ambiguous and was hoping to be able to clean it up a bit by using the entity framework.I am using VB.Net 3.5 in a web application.
Update...In an attempt to internalize the different types of relationships I can form, I have been playing with this simple example and have come up with the following possibilities:And the reason why I cannot make an association between the Student and Address table is because that relationship is not enforced in the database. If I wanted an association between these two tables I would need to re-think the design of my database. Is that correct?
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Oct 6, 2010
I have a gridview which I databind to EntityModel This typically looks like
something a
something b
companyID
on Login I get and set the compnay which has the ID so what in essence I want to do is on databind set the Where clause of data source to what the server side paramter for company ID is. I am sure this is super simple but it is driving me nuts
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Jun 27, 2011
We are currently developing a WPF/Entity-Framework based application.One of our requirements was to allow the user option to select which environment(testing, training, or production) they will connect to when logging in.Each connection option points to its own database.In order to do this we are creating new EF contexts in the following way:[code]We have made sure that all new contexts are being disposed of once its job is completed.The problem is this: when the users are using the application we are seeing hundreds of SQL Server processes in SQL Server's activity monitor. Some individual users have upwards of 30+ processes associated when using the app. Once the user shuts down the app the associated processes all disappear - but while the app is running these processes seem to stick around.
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Aug 23, 2011
I'm using an Entity Framework context, and sometimes would like to create a transaction so that the client can do multiple changes and then commit/rollback them all together.However, if many changes were made, and SaveChanges() was called multiple times, after which a rollback is called, entities that were commited already, will remain the way they were commited, and would not roll back.Here's how my transaction-relative functions look like:
Public Sub BeginTransaction()
Dim context = HttpContext.Current.GetObjectContext()
If Not context.Connection.State = ConnectionState.Open Then
context.Connection.Open()
End If
[Code]...
Not only does the test fail, but it also leave the ObjectContext in an unstable mode, because it still has invalid changes in it.
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Jul 27, 2011
I am trying to build a survey engine from an existing database design which is like this.
[Code]...
The line Order By Key.RecordOrder throws a null reference exception and I can understand why. Can someone advise on how to resolve this by just modifying this one query? I am fairly new to LINQ and the necessity to write this project
[Code]...
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Jul 22, 2009
I want to update an entity without loading the entity from the database first. I've accomplished this but only by knowing all of the entities properties and then using the "attachto" method. My issues is i don't want my app to need to remember all of the properties. Example:
[Code]....
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Dec 14, 2011
Entity Splitting: one class, two or more tables.Here is how it is done in C#, but I need to get it working in vb.net.One more thing: the class name and table columns do not match, so I have to be able to map that out, too.I have to get this to work this way because the place I'm working at right now is a vb.net only shop and the database schema is fubar, but they have so much (millions) of lines of code done directly against the database in both asp classic, vb.net, AND asp.net webforms that changing the schema right now is not realistically possible.
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Post>()
.Map(m =>
[code]....
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Jan 16, 2011
I am trying to jump from ASP Classic to asp.net. I have followed tutorials to get Entity Framework and LINQ to connect to my test database, but I am having difficulties figuring out ExecuteQuery(). I believe the problem is that I need an "entity class" for my database, but I can't figure out how to do it. Here is my simple code:
Dim db as New TestModel.TestEntity
Dim results AS IEnumerable(OF ???) = db.ExecuteQuery(Of ???)("Select * from Table1")
From the microsoft example site, they use an entity class called Customers, but I don't understand what that means.
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Feb 11, 2011
I am trying to create a generic typed class, but am running into a problem. Here is my basic class definition:
public class QueueObject<T> where T : System.ServiceModel.DomainServices.Client.Entity
{
public string LoadingMessage { get; set; }
public System.ServiceModel.DomainServices.Client.EntityQuery<T> Query { get; set; }
}
I am trying to add instances of this class to a queue
private Queue<QueueObject<Entity>> _queue;
this._queue.Enqueue(new QueueObject<MyEntity> {Query = MyContext.GetMyEntitiesQuery(), LoadingMessage = "Loading some stuff"});
This doesn't work. I get an error saying that QueueObject cannont be converted to QueueObject. I don't understand because MyEntity inherits from Entity.
Public Class QueueObject(Of T As System.ServiceModel.DomainServices.Client.Entity)
Public Property LoadingMessage As String
Public Property Query As System.ServiceModel.DomainServices.Client.EntityQuery(Of T)
End Class
[code]....
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Aug 14, 2011
I want to automatically generate VB.NET forms using tables from a SQL Server database (one form / database table). It is perhaps possible with writing custom custom code for it, but if there is already some feature that does the job that would be great (database has 40+ tables, manually doing this is a tedious task).
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Nov 9, 2010
I have installed Crystal Reports and am using it in Visual Studio 2005. how i can use SQL Server 2000 to generate reports using Stored Procedures.
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Mar 28, 2012
how to display Auto Generate number in textbox from sql server 2005 column serial_no when click the menustrip object. Here is the sample code which i tried but it not working.
Public Sub serialnogenerate()
connect()
sqlquery = "select c_slno from newconnection"
[Code].....
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Apr 10, 2012
i wanna generate an HTPASSWD file for my Server to secure a directory. For Crypt im using DesEncrypt Method , here is my Code :
[Code]...
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May 13, 2010
c# - Are Microsoft Entity Framework and ADO.NET Entity Framework (.edmx) the same?
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Sep 1, 2011
Assuming an architecture as such.MODEL > BLL > DLL
Trying to implement lazy loading in my MODEL I have run into a circular dependency between my MODEL and BLL..Basically imagine a property in my model that I want to implement as follows
Public Readonly Property ProjectCategory As ProjectCategory
Get
If Me._ProjectCategory Is Nothing Then
Me._ProjectCategory = ProjectCategoryBLL.GetProjectCategoryByID(Me._ProjectCategoryID)
End If
[Code]...
I have my MODEL, BLL and DLL in separate projects and because of the fact that my BLL references my model I can not reference my BLL from my model as this would create a circular dependency.
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May 24, 2012
I'm quite new to MVC and while I've been trying to follow the best practices , I believe I may not be understanding certain fundamentals of either
-a. Using models and viewmodels appropriately
-b. Passing models into a controller for validation purposes.
The general purpose of my program is to select a stored procedure from a list of stored procedures, create a form where the user can fill out all the appropriate input variables, and then to execute that stored procedure. The tool is for non-technical people, so I'm eventually going to have to do a good deal of input validation.
As such I have four models: A Script Model, a Parameter Model, a Parameter Enum model and a Query Model, and two viewmodels: a paramviewmodel that generates the form to fill out, and a scriptviewmodel that creates a listbox filled with the possible script choices. I am using a prewritten database system to fill out my viewmodels in an init method in my controller (which I'm not sure is the proper way to do this?).
The viewmodels are as follows:
Imports System
Imports System.Collections.Generic
Public Class ScriptViewModel
[Code]....
I'm trying to work out the functionality. Also, I think this may be too much code in the view, even though most of it is display code.
Anyways, I have two main questions. One, does creating a model in my controller, calling an init method on it, and then passing it to the view make any sense in an mvc context (if not, how would I proceed?). Two, if I want to perform validation on the form I output in my htmlhelper, but I want to use my query model validation (and not my paramviewmodel), how can I do that? Most of the examples I've seen involve a controller that recieves an appropriate model variable, and the binding is performed outside the controller itself. They then just check modelstate. Is there any way I could do something similar here?
Edit: Is there any way I can make the syntax highlighting less crappy?
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Feb 13, 2011
I am trying to figure out the best way to implement a certain part of my model.I have an entity named Customer which has CustomerLocations (1-*) which have SalesOrders (1-*) which have Invoices (1-*).I want to allow them to have multiple addresses (Billing and Shipping) per customer and per location. I want to store those values in the sales orders and invoices, not a foreign key, what if they delete one of their addresses later down the road.I have tried complex types, but then they can't have multiple, can they? And having an Address entity, customer --> address (1-*) is ok, but a bit clumsy. How would you have a collection of billing and shipping addresses.?
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Mar 16, 2009
I have a repository class that defines some basic Get/Save/Delete methods. Inside these, I use NHibernate to do the work on my business entities. For example:
[code]...
However, on my User class I have some properties and collections of other objects that ideally I'd like to be lazy loaded. But of course, the ISession is created and disposed within the repository, which I guess is why, outside of that, when I try to access those properties I get a "Could not initialize proxy - no Session" error.Is my only option then to disable lazy loading when using repositories? Or is it possible (or just foolish) to somehow get the session into scope in the business layer?I do like the repository model, and NHibernate is growing on me (after lots of initial frustration trying to make it work), so what's the best way you gurus have found of using them together?
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Mar 27, 2010
Hey I am a newcomer to Visual Basic. I am using VB 2008 Express. My problem is I have a combo box filled with model #'s and I would like to have each model # correspond with a different id #, but I have no idea on how to do this, and I have found no documentation on it.
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Jun 19, 2012
how to phrase my question, but what I am trying to do is inside a for each loop set the item of a model then set the value of that item.
dim td as new project.model.mymodel create model object
For each dr as datarow in dt.rows
dim itemName as string = convert.tostring(dr("Field"))
td.itemName = "6"
next
I keep getting an error that itemName is not part of collection td
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