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  • Entity Framework 4: Inheritance and Optimistic Concurrency

    - by Mohammadreza
    Hi guys, I'm using AdventureWorks 2008 R2 database and added the BusinessEntity and Person tables to my EDMX. Then I changed the model in which the Person table inherits from the BusinessEntity table. As you may know these two tables have ModifiedDate and rowguid columns so the Person class should not have these properties because it inherits them from the BusinessEntity class. My question is, how can I modify the model to support inheritance and optimistic concurrency on both Person and BusinessEntity classes/tables on ModifiedDate property/column. PS. It also get me an error message that I have asked here. Thanks

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  • Entity-attribute-value model using codeigniter / php

    - by John Stewart
    SO I am trying to create a way to structure my database to be able customize forms. I looked into EAV pattern and here is my db structure: Table form - form_id - form_name - form_added_on - form_modified_at Table: form_fields - field_id - form_id - field_type (TEXT, RADIO etc..) - field_default_value - field_required Table: form_data - data_id - field_id - form_id - field_value so now I can store any custom form into the database and if I want to get the values for an individual form I can simply join it by "form_id" .. the problem: I want to be able to search through all the forms for a specific field value. How can I do that with EAV model? Also, I thought about just storing the custom data as a serialized (JSON) object but then I am not sure how can I query that data. Please note that I am using Codeigniter with MYSQL. So if conversation can use Codeigniter libraries if needed.

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  • Generate SQL Server Express database from Entity Framework 4 model

    - by Cranialsurge
    I am able to auto-generate a SQL Server CE 4.0 *.sdf file using code-first generation as explained by Scott Guthrie here. The connection string for the same is as follows: <add name="NerdDinners" providerName="System.Data.SqlServerCe.4.0" connectionString="data source=|DataDirectory|NerdDinner.sdf"/> However if I try to generate an mdf instead using the following connection string, it fails to do so with the following error - "The provider did not return a ProviderManifestToken string.". <add name="NerdDinners" providerName="System.Data.SqlClient" connectionString="data source=|DataDirectory|NerdDinner.mdf"/> Even directly hooking into a SQLEXPRESS instance using the following connection string fails <add name="NerdDinners" providerName="System.Data.SqlClient" connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=NerdDinner;Integrated Security=True"/> Does EF 4 only support SQL CE 4.0 for database creation from a model for now or am I doing something wrong here?

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  • Using Entity Framework (code first) migrations in production

    - by devdigital
    I'm just looking into using EF migrations for our project, and in particular for performing schema changes in production between releases. I can see that generating SQL (delta) script files is an option, but is there no way of running the migrations programmatically on app start up? Will I instead need to add each delta script to the solution and write my own framework to apply them in order (from the current version to the latest) on bootstrap?

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  • Why should I use Entity Framework over Linq2SQL ...

    - by Refracted Paladin
    To be clear, I am not asking for a side by side comparision which has already been asked Ad Nauseum here on SO. I am also Not asking if Linq2Sql is dead as I don't care. What I am asking is this.... I am building internal apps only for a non-profit organization. I am the only developer on staff. We ALWAYS use SQL Server as our Database backend. I design and build the Databases as well. I have used L2S successfully a couple of times already. Taking all this into consideration can someone offer me a compelling reason to use EF instead of L2S? I was at Code Camp this weekend and after an hour long demonstration on EF, all of which I could have done in L2S, I asked this same question. The speakers answer was, "L2S is dead..." Very well then! NOT! (see here) I understand EF is what MS WANTS us to use in the future(see here) and that it offers many more customization options. What I can't figure out is if any of that should, or does, matter for me in this environment. One particular issue we have here is that I inherited the Core App which was built on 4 different SQL Data bases. L2S has great difficulty with this but when I asked the aforementioned speaker if EF would help me in this regard he said "No!"

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  • Using DateDiff in Entity Framwork on a SQL CE database

    - by deverop
    I have a method which should return a list of anonymous objects with a calculated column like this: var tomorrow = DateTime.Today.AddDays(1); return from t in this.Events where (t.StartTime >= DateTime.Today && t.StartTime < tomorrow && t.EndTime.HasValue) select new { Client = t.Activity.Project.Customer.Name, Project = t.Activity.Project.Name, Task = t.Activity.Task.Name, Rate = t.Activity.Rate.Name, StartTime = t.StartTime, EndTime = t.EndTime.Value, Hours = (System.Data.Objects.SqlClient.SqlFunctions.DateDiff("m", t.StartTime, t.EndTime.Value) / 60), Description = t.Activity.Description }; Unfortunately I get the following error from the DateDiff function: The specified method 'System.Nullable1[System.Int32] DateDiff(System.String, System.Nullable1[System.DateTime], System.Nullable`1[System.DateTime])' on the type 'System.Data.Objects.SqlClient.SqlFunctions' cannot be translated into a LINQ to Entities store expression. Any ideas what I could have done wrong here? EDIT: I also tried the EntityFunctions class mentioned here, but that did not work as well. Minutes = EntityFunctions.DiffMinutes(t.EndTime, t.StartTime),

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  • Entity Framework - refresh objects from database

    - by Nebo
    I'm having trouble with refreshing objects in my database. I have an two PC's and two applications. On the first PC, there's an application which communicates with my database and adds some data to Measurements table. On my other PC, there's an application which retrives the latest Measurement under a timer, so it should retrive measurements added by the application on my first PC too. The problem is it doesn't. On my application start, it caches all the data from database and never get new data added. I use Refresh() method which works well when I change any of the cached data, but it doesn't refresh newly added data. Here is my method which should update the data: public static Entities myEntities = new Entities(); public static Measurement GetLastMeasurement(int conditionId) { myEntities.Refresh(RefreshMode.StoreWins, myEntities.Measurements); return (from measurement in myEntities.Measurements where measurement.ConditionId == conditionId select measurement).OrderByDescending(cd => cd.Timestamp).First(); } P.S. Applications have different connection strings in app.config (different accounts for the same DB).

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  • Creating base class for Entities in Entity Framework

    - by Thomas
    I would like to create a base class that is somewhat generic for all of my entities. The class would have methods like Save(), Delete(), GetByID() and some other basic functionality and properties. I have more experience with Linq to SQL and was hoping to get some good examples for something similar in the EF. Thank you.

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  • Why use Entity Framework over Linq2SQL ...

    - by Refracted Paladin
    To be clear, I am not asking for a side by side comparision which has already been asked Ad Nauseum here on SO. I am also Not asking if Linq2Sql is dead as I don't care. What I am asking is this.... I am building internal apps only for a non-profit organization. I am the only developer on staff. We ALWAYS use SQL Server as our Database backend. I design and build the Databases as well. I have used L2S successfully a couple of times already. Taking all this into consideration can someone offer me a compelling reason to use EF instead of L2S? I was at Code Camp this weekend and after an hour long demonstration on EF, all of which I could have done in L2S, I asked this same question. The speakers answer was, "L2S is dead..." Very well then! NOT! (see here) I understand EF is what MS WANTS us to use in the future(see here) and that it offers many more customization options. What I can't figure out is if any of that should, or does, matter for me in this environment. One particular issue we have here is that I inherited the Core App which was built on 4 different SQL Data bases. L2S has great difficulty with this but when I asked the aforementioned speaker if EF would help me in this regard he said "No!"

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  • How to bind gridview using linq/Entity Framework?

    - by Kay
    I need to bind GridView, I am using this code: ProductDBEntities db = new ProductPDBEntities(); var pro = from u in db.Products where u.PID == 1 select u; if (pro != null) { GridView1.DataSource = pro; GridView1.DataBind(); } and getting this error. System.InvalidOperationException: Sequence contains more than one element Can somebody please tell me what am I doin wrong?

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  • Type casting in TPC inheritance

    - by Mohsen Esmailpour
    I have several products like HotelProduct, FlightProduct ... which derived from BaseProduct class. The table of these products will be generated in TPC manner in database. There is OrderLine class which has a BaseProduct. My problem is when i select an OrderLine with related product i don't know how cast BaseProduct to derived product. for example i have this query: var order = (from odr in _context.Orders join orderLine in _context.OrderLines on odr.Id equals orderLine.OrderId join hotel in _context.Products.OfType<HotelProduct>() on orderLine.ProductId equals hotel.Id where odr.UserId == userId && odr.Id == orderId orderby odr.OrderDate descending select odr).SingleOrDefault(); In OrderLine i have BaseProduct properties not properties of HotelProduct. Is there any way to cast BaseProduct to derived class in OrderLine or any other solutions ?

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  • Using Sculpture with NHibernate or Entity Framework

    - by Sergei
    I recently ran across this open-source project: http://www.codeplex.com/Sculpture Sculpture is a code-generator which allows you to design your domain model and then use persistence 'molds' such as NHibernate/EF and probably more to generate repositories. It takes care of all the mapping and Data access generation. It looks like it does a heck of a lot more, but i'm pretty much sold at this point. However, i would like to know if anyone here used this for real-world solutions. If so, how well does it scale? How did the generated DAL work for you?

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  • How to get IQueryable<> from stored procedure (entity framework)

    - by mmcteam
    I want to get IQueryable<> result when executing stored procedure. Here is peace of code that works fine: IQueryable<SomeEntitiy> someEntities; var globbalyFilteredSomeEntities = from se in m_Entities.SomeEntitiy where se.GlobalFilter == 1234 select se; I can use this to apply global filter, and later use result in such way result = globbalyFilteredSomeEntities .OrderByDescending(se => se.CreationDate) .Skip(500) .Take(10); What I want to do - use some stored procedures in global filter. I tried: Add stored procedure to m_Entities, but it returns IEnumerable<> and executes sp immediately: var globbalyFilteredSomeEntities = from se in m_Entities.SomeEntitiyStoredProcedure(1234); Materialize query using EFExtensions library, but it is IEnumerable<>. If I use AsQueryable() and OrderBy(), Skip(), Take() and after that ToList() to execute that query - I get exception that DataReader is open and I need to close it first(can't paste error - it is in russian). var globbalyFilteredSomeEntities = m_Entities.CreateStoreCommand("exec SomeEntitiyStoredProcedure(1234)") .Materialize<SomeEntitiy>(); //.AsQueryable() //.OrderByDescending(se => se.CreationDate) //.Skip(500) //.Take(10) //.ToList(); Also just skipping .AsQueryable() is not helpful - same exception.

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  • .Net Entity Framework & POCO ... querying full table problem

    - by Chris Klepeis
    I'm attempting to implement a repository pattern with my poco objects auto generated from my edmx. In my repository class, I have: IObjectSet<E> _objectSet; private IObjectSet<E> objectSet { get { if (_objectSet == null) { _objectSet = this._context.CreateObjectSet<E>(); } return _objectSet; } } public IQueryable<E> GetQuery(Func<E, bool> where) { return objectSet.Where(where).AsQueryable<E>(); } public IList<E> SelectAll(Func<E, bool> where) { return GetQuery(where).ToList(); } Where E is the one of my POCO classes. When I trace the database and run this: IList<Contact> c = contactRepository.SelectAll(r => r.emailAddress == "[email protected]"); It shows up in the sql trace as a select for everything in my Contact table. Where am I going wrong here? Is there a better way to do this? Does an objectset not lazy load... so it omitted the where clause? This is the article I read which said to use objectSet's... since with POCO, I do not have EntityObject's to pass into "E" http://devtalk.dk/CommentView,guid,b5d9cad2-e155-423b-b66f-7ec287c5cb06.aspx

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  • LINQ entity query performance

    - by Abdel Olakara
    Hi all, I have a silly question. I would like to know if there is performance deference in these two quries: var cObject = from cust in entities.Customer where cust.id == cid select cust; and var cObject = entities.Customer.First( c=> c.id == cid); My query return only one record as I am querying with the primary key. But do they make any difference?

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  • How to reference using Entity Framework and Asp.Net Mvc 2

    - by Picflight
    Tables CREATE TABLE [dbo].[Users]( [UserId] [int] IDENTITY(1,1) NOT NULL, [UserName] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, [Email] [varchar](255) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, [BirthDate] [smalldatetime] NULL, [CountryId] [int] NULL, CONSTRAINT [PK_Users] PRIMARY KEY CLUSTERED ([UserId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] CREATE TABLE [dbo].[TeamMember]( [UserId] [int] NOT NULL, [TeamMemberUserId] [int] NOT NULL, [CreateDate] [smalldatetime] NOT NULL CONSTRAINT [DF_TeamMember_CreateDate] DEFAULT (getdate()), CONSTRAINT [PK_TeamMember] PRIMARY KEY CLUSTERED ([UserId] ASC, [TeamMemberUserId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] dbo.TeamMember has both UserId and TeamMemberUserId as the index key. My goal is to show a list of Users on my View. In the list I want to flag, or highlight the Users that are Team Members of the LoggedIn user. My ViewModel public class UserViewModel { public int UserId { get; private set; } public string UserName { get; private set; } public bool HighLight { get; private set; } public UserViewModel(Users users, bool highlight) { this.UserId = users.UserId; this.UserName = users.UserName; this.HighLight = highlight; } } View <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MvcPaging.IPagedList<MyProject.Mvc.Models.UserViewModel>>" %> <% foreach (var item in Model) { %> <%= item.UserId %> <%= item.UserName %> <%if (item.HighLight) { %> Team Member <% } else { %> Not Team Member <% } %> How do I toggle the TeamMember or Not If I add dbo.TeamMember to the EDM, there are no relationships on this table, how will I wire it to Users object? So I am comparing the LoggedIn UserId with this list(SELECT TeamMemberUserId FROM TeamMember WHERE UserId = @LoggedInUserId)

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  • Entity Framework 4 code-only reference column name

    - by Victor
    I created classes: public class Country { public long CountryId {get;set;} public string CountryName {get;set;} } public class Profile { public long ProfileId {get;set;} public string ProfileName {get;set;} public Country Country {get;set;} } and configuration for Profile: public class ProfileConfiguration : EntityConfiguration<Profile> { public IlluminatiCoreProfileConfiguration() { Relation(p => p.Country); } } Then I create context and run context.CreateDatabase(). New database contains table Profiles with column Country_CountryId. How can I write configuration for changing column name to "CountryId"? Thanks.

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