entity framework select

example, we can use the count () method in the Where clause of a LINQ query to check whether the number of comments is greater than 0. In the entity SQL method, we can use count in the WHERE clause (select value 1 from p.comments ) >0. Both of these methods work fine, but the approach in Listing 3-10 is more concise, and from a performance standpoint, any () and exist () do not need to enumerate the entire

Small instance of the entity Framework: Adding an entity class to the project and inserting1>. Create a console program2>. Add an ADO. NET Entity Data model, select the corresponding database and table (STUDENTMODEL.EDMX)3>. Control Table Code Static voidMain (string[

upper right corner. If it is not installed, click Download to install it. After the installation is complete, follow the steps below to optimize the code. 1. right-click the designer, select Add Code Generation Item, and select ADO. net poco Entity Generator, and enter Entities in the Name text box. tt: Click OK. The two files are added to the project: Entities.

Http://www.cnblogs.com/sansi/archive/2012/10/18/2729337.htmlProgramming Entity Framework Second Edition translation indexYou can query the Entity Data model using various methods. You choose some methods because of your personal preferences, while others are because you can take advantage of special benefits. You've probably heard LINQ to Entities and

Entity Framework Quick Start -- ModelFirst, entity -- modelfirst Entity Framework not only facilitates operation, but also considers user friendly interaction. The perfect combination of EF4.0 and vs2010 is also a reason for us to choose it. Compared with Nhibernate Microsof

]. [IsActive2] As [Isactive1]from (SELECT [extent1].[ ID] as [id], [Extent1]. [Title] As [Title], [Extent1]. [UserId] As [Userid1],[extent1]. [IsActive] As [Isactive1],[extent3]. [UserID] As [UserID2], [Extent3]. [IsActive] As [IsActive2], Row_number () over (ORDER by [extent1].[ QID] DESC) as [Row_number] from [dbo].[ Question_item] as [Extent1] INNER JOIN [dbo].[ Users] as [Extent2] on [Extent1]. [UserID] = [Extent2]. [UserID] Left OUTER

In the RAFY domain Entity Framework, the self-associated entity structure has been specially processed, and this function is explained below. Scene When you develop a database application, you often encounter scenarios in which you have self-correlating tables. For example, classification information, organizational structure of the Department, folder

other databases, such as SQL Server ce, MySQL, Oracle, and vistadb. Create a new console application project by selecting the console application project template (see Figure 2-1 ). I name it chapter2consoleapp. Reminder: Make sure that the project is a. NET Framework 4 Project. You can see the filter menu at the top of the new project window. Many of the features in this book are not available in. Net 3.5. If you choose the wrong one, y

This article is ADO. NET Entity Framework Series of articlesArticle 3: continue to demonstrate how to use the entity of ADO. NET Entity Framework as the data source of the data control to easily display data records in the Data Control. ADO. the first two articles of NET

ArticleDirectory Entitycontainer Entityset Entitytype Association Navigation Properties Returns the navigation attribute of the set. Programming Entity FrameworkVersion 2Translation Index Metadata supported by the Model So far, you have only seen the concept of the model in the designer, and its edmx has a more important part: storage model and ing. Note: in fact, the edmx file contains four parts, but the fourth part

list: Using system. Data. objects; ... Using (var edm = new northwindentities ()) { String esql = "select value c from northwindentities. MERs as C order by C. customerid limit 10 "; Objectquery Objectresult Foreach (customers C in results) Console. writeline (C. customerid + ":" + C. companyName ); Console. writeline (query. totracestring ()); } In EDM, entitycontainer is represented by a Class inherited from objectcontext (

entity Framework support:You must remember to install the entity Framework support for Vs 2017:3, restart Visual studio2017, and add the ADO Entity Data Model again.Finally there is the MySQL database option.4, add the latest version mysql.web.6.9.9, mysql.data.6.9.9, mysql

Http://www.cnblogs.com/dudu/archive/2012/04/13/entity_framework_include_where.htmlIn the Entity Framework, if entity A is associated with entity B, you want to load entity B while loading entity a. It is common practice to use inc

When you generate an ADO. NET Entity Data Model (Entity Data Model) through a database, the number of entity classes generated may be less than the number of data tables. The following describes two possible causes. 1. All columns of the data table can be empty. When a data table has a primary key, the object data model uses the primary key as the

Entity SQL is the SQL class language provided by the Ado.net Entity Framework to support the Entity Data Model (EDM). Entity SQL can be used for object queries and queries executed using the EntityClient provider. L Key Words Value keyword ESQL provides a

Entity Framework 6 Recipes 2nd Edition (9-5) Translation-> delete a disconnected Entity, entityrecipes 9-5. delete a disconnected entity Problem We need to delete the object retrieved from WCF. Solution Let's assume that we have the payment and Bill model of the entity as sh

The original purpose of the translation and why choose the Entity Framework 6 Recipes to learn, please see the beginning of this series2-10 Table per Hierarchy inheritance modelingProblemYou have a database table that has a type or identification column. It can tell what the data in the row represents in your application. You want to model using table per hierarchy (TPH) inheritance mapping.Solution Solutio

Entity Framework 6.0 supports enumeration/the primary key is reversed after the Entity is added. entityframeworkLab Go directly to the code and view the result Entity class [Flags] public enum FlagsEnum { Day = 1, Night = 2 } public class EntityWithEnum { public int ID { get; set;

class in the class designer, right-click the class in solution manager, and select View class diagram. In the default view, click "sampleentities" in the upper-right corner. This class uses the entitycontainer name of the model. Others are each entity, address, contact, and vofficeaddresses. Objectcontext class, smapleentities When you view the XML view of the model in Chapter 2nd, you can see the ent

Entity Framework learning notes-EF introduction (an article tells you what EF is), entity learning notes Entity Framework is a data-oriented "Entity Framework" based on ADO. NET ". EF.