ADO.NET :: Mapping Data To Business Entity Collection?
Aug 10, 2010
I'm having a trouble figuring out how I am going to map my business objects. I found this little mapper using reflection with a little modification :http://www.simple-talk.com/dotnet/.net-framework/a-defense-of-reflection-in-.net/Above works fine and fill out my Business objects properly. But what if I have relationship on the Business objects class like for example :
[Code]....
then a User Class will have a relationship with Roles like :
[Code]....
Assuming there are columns on the database that have the RoleID, RoleName, UserID, UserName by Joining the 2 tables. The problem here is that the Mapper doesn't map the Roles properly since the Mapper will expect a Column Name "Role". I tried also inheriting the roles instead of instantiating it but it doesn't work either.I'm using a 3-tier Architecture (including a sublayer "Business Objects") and List<T> combo.
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Feb 10, 2011
I am mapping a stored procedure to an entity by right clicking on the entity (in the .edmx) and selecting "Stored Procedure Mapping." This brings you to a Mapping Details - "Name of Entity" Window that allows you to select the insert, update, and delete stored procedures associated with the Entity. It also maps the stored procedure parameter to the Entity "Property" (Column).
I'm gettin an error "error 2042: Parameter Mapping specified is not valid." The cause of the error is fairly obvious, in the Insert stored procedure that has been selected, a 'CHAR' parameter is being mapped to an Int32 Entity Property. I altered the stored procedure parameter to match the entity, I deleted the stored procedure, readded, and reslected it as the Insert function. I also cleaned, validated, updated model from database. No matter what I do, the parameter list in the mapping details doesn't reflect the change to the stored procedure. It's stuck on a char --> int32 mapping, even though it has been changed, like it's buried deep in meta data some where.
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Sep 2, 2010
As I began writing web applications with asp.net I started with small projects that used a Linq-To-SQL mapper for database access to a MSSQL Server. After gaining some expierence I switched into a classic 3 tier with Graphic Layer, Business Layer, Data Layer. The only function of the Data Layer was to provide methods insert/update/delete without any logic and logic the form of selection methods.
Over the time I realized that it would be better not to provide the database classes up to the GUI (took some time unfortunately). I switched into using Business classes in the BL that are used for all operations performed by the BL and display by the GUI in the form of getting List from the BL. A great advantage is that I can provide additional properties that are not represented by the database itself. However, I did that mapping inside the BL myself with methods that mapped the corresponding BL class to the database class.
I guess thats where O/R mapper come in handy? Until now I haven't realized their purpose, but I think I just found it. I've recently tried out using the new Entity Framework with .net framework 4, but I'm only using it like the Linq-To-SQL DataContext.
Is there a way to achieve the mapping automatically? If yes, is that something the new Entity Framework provides or do I need to look for a O/R Mapper like NHibernate?
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Feb 5, 2010
I have two business objects mapped via LINQ to tables. One of the objects contains an instance of the other object and share a key as an identifier.I want to retrieve Class A and within class A all of Class B's values as well. What I am doing is this:
[Code]....
[Code]....
This seems a little clunky, as in slow. Is there a better way to get the Class B (User) information without making a query every time?
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Jan 18, 2010
I have three table like above, table C is mapping table which has foreign key of Table A and B.How can i select and insert data in Table C using Entity Frame Work?
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Jun 26, 2010
The method has a return type of collection<businessEntity>, i am calling the method from the aspx page in order to populate a drop down -> ddlDropDown. I am binding he DataTextField of the ddlDropDown with the BusinessEntity.Name and the DataValueField with BusinessEntity.Id, the business entity contains another id which is BusinessEntity.ProductId. I need to use the ProductId of the value selected in the drop down list in the code behind.
One possible way could be to call the method in the page_Load on the code behind and save the collection in a hidden variable and when required do a loop through in the hidden variable and retrieve the selected value Product Id.
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Feb 8, 2011
I hope I am asking this in the right forum as I need an answer quick. I have a table in my database called PersonalData. In my application I have a model for PersonalData that looks like this:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.Globalization;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Security;
using System.Data.Entity;
using System.Data.Entity.ModelConfiguration;
namespace MyApp.Models
{
public class PersonalData
{
[Key]
public Guid PersonalDateGuid { get; set; }
[Required]
public Guid fkUserGuid { get; set; }
[Required]
public int fkProviderId { get; set; }
[Required]
public int SourceSystem { get; set; }
[Required]
public int DataType { get; set; }
[Required]
public int ModifiedDateTime { get; set; }
public int ValTinyInt { get; set; }
public int ValInt { get; set; }
public float ValDec { get; set; }
public string ValStr { get; set; }
public int Sync { get; set; }
}
}
When I try to add a new record it tries to automatically pluralize the table name and gets an error that says "{"Invalid object name 'dbo.PersonalDatas'."}"
So I want to do a mapping in my dbcontext class like so:
[Code]....
But I keep getting a design time error:
Error 1 'System.Data.Entity.ModelConfiguration.EntityTypeConfiguration<MyApp.Models.PersonalData>' does not contain a definition for 'MapSingleType' and no extension method 'MapSingleType' accepting a first argument of type 'System.Data.Entity.ModelConfiguration.EntityTypeConfiguration<Myapp.Models.PersonalData>' could be found (are you missing a using directive or an assembly reference?)
[Code]....
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Apr 30, 2010
I have a dropdown list on an ASP.NET MVC project that I am pretty sure is not binding to my model because of my nhibernate mapping. I have tried many variations on the asp mvc side resulting in this post here.
MVC side of things seems fine I believe the issue may be that my object is trying to bind, but my mapping is out of whack.
My mapping is:
<many-to-one name="Project" lazy="false"
class="AgileThought.ERP.Domain.Property.Project"
column="ProjectGUID" />
My View gives an error saying that the GUID from the dropdownList selected value is not valid. Which I think may be that it is trying to push the GUID into my related project object.
The value 'fd38c877-706f-431d-b624-1269184eeeb5' is invalid.
My related project list binds to the dropdown list just fine, it is just not binding to my models Project entity.
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Feb 22, 2011
I am using .Net 3.5, VS2008, MSSQL2008 I would like to perform CRUD operations through SP and want the SP to be bound to custom entities
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Jan 4, 2010
I have a stored procedure that search a view using full text.
I'm trying to map the results to an existing Entity (Sales), where I mapped the column MivType to SaleType (as it makes more sense, and I want to keep db names away from my web site). The stored procedure is mapped to a Function Import, and I've defined its ReturnType to Sales.
This work well as long as the entity has the same property names as fields names.
Here's my problem: when I change the property's name, I get the following error after running the imported function:
The data reader is incompatible with the specified 'Model.Sale'. A member of the type, 'SaleType', does not have a corresponding column in the data reader with the same name.
I can fix this if I change the property 'SaleType' to 'MivType' on the entity, but why should I do that? Isn't that what the mapping is for?
This means I have to use the exact same names on the stored procedure and the entity, so in effect, the mapping is ignored (I have names like YzrName, MivYaad, etc, and I don't like it).
Is there a simple way around this? I don't want to use the db names on my application, and prefer not to change the stored procedure...
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Feb 8, 2011
For the death of me I cannot remember how I got this right the last time.
I got 2 tables in my database, tblClients and tblOrders
[Code]....
[Code]....
In my project I got an Client and Order class
[Code]....
[Code]....
I create and edmx and then a "context" class (forgot most of EF stuff. This is just a quick demo I got to have ready)
[Code]....
However, when I run I get this error: Mapping and metadata information could not be found for EntityType 'ClientManager.Domain.Client'.
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Jun 26, 2010
The method has a return type of collection, i am calling the method from the aspx page in order to populate a drop down -> ddlDropDown. I am binding he DataTextField of the ddlDropDown with the BusinessEntity.Name and the DataValueField with BusinessEntity.Id, the business entity contains another id which is BusinessEntity.ProductId. I need to use the ProductId of the value selected in the drop down list in the code behind.
One possible way could be to call the method in the page_Load on the code behind and save the collection in a hidden variable and when required do a loop through in the hidden variable and retrieve the selected value Product Id.
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Jun 26, 2010
Question. Say for example if i have a business entity -> Customer, which has customerId, customerName and customerType. I have created an asp:Hidden Variable hdnCustomer to runat="server"
If i wanted to serialize the value of the customer business entity (in the code behind) to the hdnCustomer then how would i do that?
// Psudo code
Collection customerList = new Collection();
customerList = BusinessAccess.GetCustomerList();
hdnCustomer = serialize and assign the value of 'customerList' to hdnCustomer;
...
...
// Later on a select index change of one of the drop down lists
inside the event handler for the drop down list
{
Collection customerList = new Collection();
customerList = deserialize the value from hdnCustomer
int a = Convert.ToInt32(ddlDropDown.SelectedValue);
foreach(a in customerList)
{
// Do something
}
}
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Sep 27, 2010
Im using Entity framework with POCO entity generator template + SQL Server. I have mapping to stored procedure that takes two floats as input.
After executing function from code with two doubles as parameters: 1.23 and 4.56, SQL Profiler shows:
exec storedProcedureName @arg1 = 1,23, @arg2= 4,56
This is causing an error because it looks like that stored procedure takes 4 arguments, but it should take only two and there should be dots insted of commas in these floats.
[code]....
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Feb 2, 2011
I have an ASP.NET application with existing business classes and a database schema. (which I would like to keep) Currently I am using ADO.NET for the DAL, but I would like to switch to some advanced technology there for easier data retrieval.
Is EF applicable to my situation? Can I use it without splitting up my business classes and auto code generation? Can LINQ to SQL solve my problem better?
All I want to do is map my existing classes to the existing tables and dont have to handle details of the data retrieval myself.
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Mar 28, 2011
I've got a GridView on a ASP.Net page. I would like to set the DataSource of the Gridview to a trackable collection of Entity Framework objects. I though the code should look like this:
this.gvMyGridView.DataSource = entity.MyDetailedItems;
this.gvMyGridView.DataBind();
But this doesn't display any data.
I am using self tracking entities and the MyDetailedItems is a navigation property to rows from another table.
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Feb 28, 2011
I'm trying to have a View where the user can add items in a collection without having to go to a new View (the scenario is a sort of CV site where the user adds info about work experience, skills, etc, and it would seem absurd to go to a new View to add each little thing).
So I have an edit View that shows a number of text boxes for the already added items, and there's an ajax call to go to a method to fetch the collection fresh if the user adds an item.
Here are the methods in question:
[code]....
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Aug 6, 2010
I'm new to LINQ and EF and I seem to be having trouble working this out.
I have a many-to-many relationship between my Location and Region tables. When adding or editing a Location, my interface allows the user to check any number of related Regions. If they click OK, I need to add any new relationships that were checked, and delete any existing relationships that have been unchecked. My basic code is shown below.
However, this code doesn't work. Lower down, the line location.Regions.Contains(region) returns false even when the location already is related to the region. The issue appears to be because the region is from my populated listbox that was initialized earlier and is no longer part of the current EF context. But if I try and add it, I get an error that there is already a Region with that ID.
It seems like what I want to do is change this line to something like location.Regions.Contains((r) => r.RgnID == region.RgnID) so I'm only testing for a particular ID. But this gives me the error "Cannot convert lambda expression to type 'TrailCalendar.Region' because it is not a delegate type."
I don't understand this error but, either way, I'm not sure how I can test if the relationship already exists without reloading a bunch of data, which I'd like to avoid.
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Nov 23, 2010
here my code-
List<ReservationSlotLimitDetailEntity> sorted = (from p in slotLimitCollection.OfType<ReservationSlotLimitDetailEntity>()
where p.DayOfTheWeek == dayOfTheWeek
select p).ToList<ReservationSlotLimitDetailEntity>();
I want to sort in such a way so that it will add on more temp column "DayName" based on condition such that if dayOfTheWeek==1 DayName=Monday and if dayOfTheWeek==2 DayName=Tuesday and so on.
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Feb 20, 2011
I want to be able to update a model and all its collections of child objects in the same view. I have been referred to these examples: http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx and http://blog.stevensanderson.com/2010/01/28/editing-a-variable-length-list-aspnet-mvc-2-style/ .
For example, I have an object Consultant, that has a collection of "WorkExperiences". All this is in an Entity Framework model. In the view, the simple properties of the Consultant object is no problem, but the collection I cannot get a textbox to show up for. I tried following the examples in the links above, but it doesn't work. The problem is, in those examples the model is just a list (not an object with a child list property). And also, the model again is an EF model. And for some reason that doesn't seem to work as in those examples.
[Code]....
This stuff with the EditorTemplate works fine in Phil Haack's sample project, which I downloaded to try, but here, with the EF model or whatever the problem is, I don't get any textbox at all. The table in the view is just there as a test, because in the table I do get the rows for WorkExperiences, whether I add an empty WorkExperience object or fill out its properties doesn't matter, the rows show up for each object. But again, no textbox...
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Sep 28, 2010
In an MVC view, I'm looking for a way to determine if a parent entity's collection of child entities is empty, so I can decide if I need to call a RenderPartial() or not.
For a one-to-one I've been using the following:
<% if (Model.Book.GenreReference.EntityKey != null) %>
{.....}
but I'm unsure how to do it in a one-to-many scenario, or if it can even be done without the use of Include() or Load().
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Jul 26, 2010
I have a list of objects that I want to bind to a gridview. Creating that list and binding it works fine for most of the public properties in that list.
There are some objects contained in each of those objects... for instance there is an Address object.
object.Address.Line1;
object.Address.Line2;
When I bind this to my gridview, I have no issues with stuff like object.DateRegistered, but how can I access things like object.Address.WhatEverProperty? I always get this error:
"A field or property with the name 'xxx.xxxx' was not found on the selected data source."
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Mar 31, 2010
I want to know that how i use the collection class for storing some data and save it letter in the data base.
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Sep 29, 2010
getting data from multiple Entities models into an MVC controller. Most of the examples I have seen for using EF in an MVC2 app only use a single entitiy.
I have just started using MVC2 in C# using the Entity Framework models (CIOps.model) created from an SQL database. I can create the controller and views using single tables of the model in MVC2, but I just cannot get my head around how to get data from multiple entity tables into the controller (similar to joins in T-SQL). I have included an example below of the controller code that works with a single entity table, tbl_tours (tbl_tour in DB).
Could someone please illustrate how this code would be changed to include additional columns from FK tables in addition to tbl_tours columns. E.g. the clients name from the tbl_clients, the coordinators name from the tbl_employees, and costs from tbl_costs entities? Is it possible to do this directly using the EF model entities/classes that are already created and not use LINQ, POCO, Repositories, etc.? The FK relationships are already in the EF models. I have included the whole controller code, but I just need a few examples of how to join the multiple entities, not rewrite every CRUD function function in the controller. I think this will get me over the hump in using EF in an MVC2 App. Also ignore the fact I am using the home controller, this will change in the application.
[Code]....
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Aug 5, 2010
I am trying to add a new entity and have to refernce associated data to add it. I cannot load the Referencetables. Giving "The EntityReference could not be loaded because it is not attached to an ObjectContext." How do i complete this task in Entity Framework 3.5
[Code]....
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