Most voted "entity-framework" questions
ADO.NET Entity Framework is a set of tools for object-relational mapping or Object-Relational Mapping (ORM) for the . NET Framework by Microsoft, Since version 3.5 SP1.
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answer75
viewsObject Type Declaration Doubt - Entity Framework
I need help in defining the correct class statement Follows my code: public void BuscaOcorremcias() { //Op 01 - Declarando um IList da Model IList<Ocorrencia> ocorrencias = null; //Op 02 -…
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answer297
viewsEntity - Multiplicity Constraint violated
I don’t understand the reason for this error in Entity. Could you give me a help? Error: The role 'Occurrence_occurrence_target' of the Relationship 'Addresseb.Models.Occurrence_occurrence' has…
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answer71
viewsCodefirst Entity Framework database, 1-0.. 1, 1-N
I have 3 tables and need to relate them via code (Code First) I would like to know how to do this. I already have the following table codes: Tbhistoricoanalogic using System; using…
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answers232
viewsInheritance with Entity Framework
I have a doubt in the inheritance part, I have the person and user classes. Person has its basic attributes and the user inherits from the person. So far so good is right. My problem is that in…
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answer162
viewsWhat does everything in this method do? (Mirror Audit in Entity Framework)
Well, following this excellent reply of the Gypsy, where he implements a form of Auditoria Espelho, where it is implemented in the DbSaveChanges() the following method: //Laço de repetição em…
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answer463
viewsError saving list of related objects
I’m using the BeginCollectionItem to insert objects related to a Cliente which I call Dependentes. When saving, I have the mistake: Violation of PRIMARY KEY constraint 'Pk_dbo.Dependents'. Not…
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answer345
viewsProblems when mapping Entity Framework database
I’m having trouble creating a solution to this business rule. I currently have 1 Customer, 1 Correspondent and 1 Store. Both use the same address table. Like the tables cliente, correspondente and…
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answer77
viewsError in Transactionscope
I’m trying to accomplish a TransactionScope but it always gives me a mistake: Server Error in Application '/'. A Second Operation Started on this context before a Previous asynchronous Operation…
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answer167
viewsEdit object, with related objects
I Have an Object Cliente relating to two other objects. [Table("Cliente")] public class Cliente { [StringLength(100, ErrorMessage = "Este campor permite apenas 100 caracteres"), Required] public…
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answer112
viewsCreation of anonymous objects vs "named (?)"
I have a class that loga some information in the database I am using it in the following way: new StudyLogRepository().Create(new StudyLog() { StudyId = Study.Id, CycleId = null, DateOccurrence =…
c# asp.net-mvc .net entity-framework pattern-designasked 7 years, 11 months ago Jhonatan Jorge de Lima 1,012 -
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answer40
viewsEF relationship from Foxpro migration, with composite key
I’m migrating a legacy Visualfox system on . Net where the tables were made all without relationship, in ADO, without Foreign key in relationships. Just comparing a string of the name "Type" to…
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answers464
viewsSave Objects Relationship Only - Entity Framework
Using the . Net platform with the Entity Framework. I am persisting an A_B class object that relates to A and B as code below: public class A_B { private int Id; private string name; private A a;…
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answer293
viewsHow to map the results of a previous store to an entity using Entity Framework?
Personal talk. I’m doing a project with MVC 4 and EF6. I’d like to call in a proc and her results populate an entity. But my entity is not a bank table, so I did not use Dbset on it. What happens is…
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answers373
viewsInheritance in Entity Framework
I have the following structure: Table: Services (Services table) - with the common properties of all services + Type + Serviceid Table: Service 1 (Service table 1) - with service properties 1 Table:…
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answer75
viewsI want to search information of a table with EF
I have the following form code: @model Domain.Entities.Tabela1 @using WebUI.HtmlHelpers @using WebUI.Extensions @{ ViewBag.Title = "Tabela"; Layout = "~/Views/Shared/_Master.cshtml"; } <article…
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answers1028
viewsHow to query containing MAX and COUNT via LINQ
I got the following model: public class Crm_Analise { [Key] public int id { get; set; } public string cod_item_CRM { get; set; } public string TAG { get; set; } public string data_creat { get; set;…
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answer111
viewsError when performing LINQ query with equals in Where enclosure
When executing the query below: public ActionResult GridViewPartial() { if (Session["cod_cli"] != null) { int cod_cli = Convert.ToInt32(Session["cod_cli"]); //var model = db.DadosTecnicos; var model…
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answer83
viewsModeling - Model
I’m having trouble creating my models. Let’s imagine that I have 4 different types of products (Here as A,B,C and D) public class Produto { public int ProdutoId { get; set; } public TipoProduto…
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answers751
viewsEntityframework - new table not created
Following this tutorial the tables were created all right. Then I took a test, created a new entity, did the update-database and no creating the table in SQL Server 2012. I made some changes to the…
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answers122
viewsWhen consuming a service, error occurs in float or double fields in BD
When consuming the update service, this error occurs: The 'Datalib' Property on 'Release' could not be set to a 'System.Double' value. You must set this Property to a non-null value of type…
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answer135
viewsBank without PK, but I checked the PK by the Entity. Is this a problem?
I’m having trouble with fields float. Well, that post will deal with another matter, but I thought I could somehow infer in this problem. I stopped to think and analyze the subject. This is the…
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answer53
viewsWhen there is no string specification with the configured class where the Entity Framework creates the tables
I created a new project using Asp.Net MVC with EF, and did not configure the connection string property with the same name as the Context class : Dbcontext. Rodei enable-Migrations -> worked…
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answer298
viewsHow to make a SUM in different table fields in the Entity Framework?
That’s the SQL that I have as an example, I would like to do the same with Linq? select SUM(iv.precoMediano * oi.quantidade) as total from orc_orcamentoItem oi inner join orc_insumoValor iv on…
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answer544
viewsCheck null or empty fields in an entity without consecutive use of "if-Else"
In a system integration there are data updates on both sides, where you get the record of Side A and the record of side B. If there are null fields in A and these exist in B then A is supplemented…
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answer128
viewsError using Code First From Database
I’m trying to use the Entity Framework with a Sqlserver database that I created outside of Visual Studio. The problem is that when I add the ADO.NET Entity data Model to the project to do the…
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answer468
viewsTransactionscope - Rollback problem
I need the Transactionscope do Rollback case any of these foreach error. I added a Exception manually between 2º and 3º foreach to test whether the rollback, but the information saved in the bank of…
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answers1332
viewsRelationship one for many and many for an Entity Framework
I am developing these classes of this diagram, but I am in doubt how to declare relationships [One for many, and many for one] This is the diagram: for example Product has a Category, and a Category…
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answers298
viewsEF Core Relationships one-to-Many-to-Many Fluentapi
Good afternoon, I’d like to take a relationship question from Entity Core. I have a table person and the person has a position (Manager, supervisor, responsible, etc..) public class Pessoa { public…
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answer70
viewsDoubt about which Inheritance to use in the Entity Framework
I only had the opportunity to use the EF basically 1x. Therefore, I am with many doubts, even consulting a lot google. I have a client application that will take various data from the logged user’s…
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answer706
viewsImplicit conversion of the nvarchar data type into varbinary(max) is not allowed. Use the CONVERT function to perform this query
Follows code: byte[] image1 = ConvertTo.Bytes(Request.Files[0]); byte[] image2 = null; ctx .Users .Where(x => x.Id == 1) .Update(x => new User() { ImageByte1 = image1, ImageByte2 = image2 });…
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answers679
viewsEntity Relationship Framework 1:N
Hello. I have the following classes... Sales class: [Table("venda")] public class Vendas { public Vendas() { ItensVendas= new List<ItensVendas>(); } [Key] public int Id { get; set; } public…
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answers123
viewsHelp with LINQ, query no . Net
Good morning, guys, I could use a little help with LINQ. I am trying to perform the following query through the: SELECT NFE_SAIDA.NFESAI_SEQUENCIA FROM CAD_NFE_SAIDA NFE_SAIDA LEFT JOIN…
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answer46
viewsError when simulating distinc in query with Linq and lambda Expression
I have 2 tables in a Sqlserver bank. One tbState call and another tbCity. I am trying to return all states of the table tbState that have at least one city (tbCity) and with the properties…
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answer379
viewsConvert SQL to LINQ
I have the following table CREATE TABLE `ultimaposicaorastreadores` ( `Id` CHAR(36) COLLATE utf8_bin NOT NULL DEFAULT '', `Serial` BIGINT(20) NOT NULL, `DataGps` DATETIME NOT NULL, PRIMARY KEY USING…
c# sql entity-framework entity-framework-6 linq-to-entitiesasked 7 years, 2 months ago b3r3ch1t 805 -
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answer792
viewsEntity lambda framework with include returns empty Collection
I have a select that returns chained data and plays it in a Viewmodel created for the simple reason that I cannot return all data from my table, as in the example: var data = _context.Forms…
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answer857
viewsDoes not contain a Definition for 'Include' and the best Extension method Overload 'Queryableextensions.Include(Iqueryable, string)
Why does my code not recognize the method . Include("Category") in my Consoleapp? Where am I missing? Severity Code Description Project File Line Suppression State Error CS1929 'Ienumerable' does…
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answer98
viewsError creating an executable distribution with sql database using Entity Framework
I am developing a C# winforms desktop application in Visual Studio with Sql database through the Entity Framework. The intention is that it be a local database, the program will be installed on…
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answer501
viewsEntityframework + Sql Server + ASP.NET MVC
Hello, I have an ASP.NET MVC application that is using the ORM Entityframework to communicate with an SQL Server database! I currently switched computers and had to install everything again, Visual…
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answer1146
viewsError While Creating Migration
I am creating a user register in C#, but when including the Domain layer and I will create the Migration is happening the error below. I haven’t been able to identify what happens. "No suitable…
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answers45
viewsGroup select and return exact amount
Guys I’m using Entity and I have a query that returns some 2000 lines. After doing this: base.Get(queryParameters) .GroupBy(x => new { x.Id }) Until then it is normal,I work with pagedlist, where…
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answer40
viewsDoubt generating entity from Cs file code in edmx C#
In the version of ".Net Framework 4" I have a project that when using . edmx did the automatic generation of Edmschema where in my project I did so: 1 - ADO - (Project Class Library) 2 - Archive .…
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answers458
viewsHow to Update to Linq?
My project has the Delete method, only it definitely deletes the table record in the database. I would like to instead of delete, change the column record, I have a field called "Status", this field…
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answer181
viewsWhat is the difference between using "equals" vs == in LINQ to Entities?
As quoted above, when I say equals from LINQ to Entities I am referring specifically to the reserved word of C# and not to the Equals() of System.Object. Source: equals (Reference of C#) The…
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answer44
viewsWhat is the most efficient way to obtain a property from an Entity?
I’m using the EF6 and would like to know how to get the best performance when redeeming a unique property from a Entity. Assuming the following case: Let’s say I need to fetch all the names from a…
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answer72
viewsError in left Join Linq - Dbcomparisonexpression requires Arguments with comparable types
I have the following method: However, when I run the query in the Log, using the left Join I get the following message : Dbcomparisonexpression requires Arguments with comparable types [HttpGet]…
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answers79
viewsUnit of Work - Error: "Attaching an Entity of type 'Entityb' failed because Another Entity of the same type already has the same Primary key value"
These are my example classes: public class EntityA { public string Id { get; set; } public decimal AproveValue { get; set; } public string EntityB_Id { get; set; } public virtual EntityB EntityBs {…
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answer220
viewsC# problems loading Data Grid using Datetime
Good night. I have one dataGrid which I carry using Entity Framework, however in dataGrid my date appears MM/dd/yyyy, I want to remove the time and format the date to dd/mm/yyyy, and in the validity…
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answer111
viewsSavechanges is truncating the decimal value
I’ll rephrase the question: I need to write to the database with four decimal places. For example. In the view I type a percentage value of 56.78%. In the bank should be recorded 0.5678. That’s why…
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answers27
viewsProblems displaying data from an automatically generated table because of the relation n to n, Entity framework c#
I am using Entity Framework code first in C#, I have the following classes. Procedure (only the relevant part): public int Id { get; set; } public virtual ICollection<Produto> Produtos { get;…
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answer242
viewsAn Exception of type System.Nullreferenceexception occurred in Entityframework.dll when trying to insert given
I am trying to save a data in a table on the server using entityFramework, but is making an error of Nullreferenceexception. The insertion code is: public void CadastraFaleConosco(FaleConosco fale)…