Entity Framework Code First 利用一种被称为约定(Conventions)优于配置(Configuration)的编程模式允许你使用自己的 domain classes 来表示 EF 所依赖的模型去执行查询.更改追踪.以及更新功能,这意味着你的 domain classes 必须遵循 EF 所使用的约定.然而,如果你的 domain classes 不能遵循 EF 所使用的约定,此时你就需要有能力去增加一些配置使得你的 classes 能够满足 EF 所需要的信息. C…
声明:本文只针对 EF6+ 默认情况下,Code First 对实体进行插入.更新.删除操作是直接在表上进行的,从 EF6 开始你可以选择使用存储过程(Stored Procedures) 简单实体映射 Basic Entity Mapping 注意:本文将使用 Fluent API 来配置使用存储过程 public class Blog { public int BlogId { get; set; } public string Name { get; set; } public strin…
上一篇文章我们讲解了如何用 Fluent API 来配置/映射属性和类型,本文将把重点放在其是如何配置关系的. 文中所使用代码如下 public class Student { public int ID { get; set; } public string Name { get; set; } public DateTime EnrollmentDate { get; set; } // Navigation properties public virtual Address Address…
上一篇文章我们讲解了如何用 Fluent API 来配置/映射属性和类型,本文将把重点放在其是如何配置关系的. 文中所使用代码如下 public class Student { public int ID { get; set; } public string Name { get; set; } public DateTime EnrollmentDate { get; set; } // Navigation properties public virtual Address Address…
Code First development with Entity Framework: Entity Framework supports three different development approaches to use entity framework in your application. Code First Model First Database first Code First: In the Code First approach, you avoid workin…
Lazy Loading: One of the important functions of Entity Framework is lazy loading. Lazy loading means delaying the loading of related data, until you specifically request for it. For example, Student class contains StudentAddress as a complex property…
Eager Loading: Eager loading is the process whereby a query for one type of entity also loads related entities as part of the query. Eager loading is achieved using the Include() method. In the following example, it gets all the students from the dat…
Enum in Entity Framework: You can now have an Enum in Entity Framework 5.0 onwards. EF 5 should target .NET framework 4.5 in order to use Enum. Enum can be created for the following data types: Int16 Int32 Int64 Byte SByte You can create and use an E…
Stored Procedure in Entity Framework: Entity Framework has the ability to automatically build native commands for the database based on your LINQ to Entities or Entity SQL queries, as well as, build the commands for inserting, updating, or deleting d…
Concurrency in Entity Framework: Entity Framework supports Optimistic Concurrency by default. In the optimistic concurrency, EF saves the entity to the database, assuming that the same data has not changed since the entity was loaded. If it determine…
Update Entity Graph using DbContext: Updating an entity graph in disconnected scenario is a complex task. It is easy to add a new entity graph in disconnected mode, but to update an entity graph needs careful design consideration. The problem in upda…
Disconnected Entities: Before we see how to perform CRUD operation on disconnected entity graph, let's see how to associate disconnected entity graph with the new context instance. There are two things we need to do when we get a disconnected entity…
Change Tracking in Entity Framework: Here, you will learn how entity framework tracks changes on entities during its life time. Entity framework supports automatic change tracking of the loaded entities during the life time of the context. DbChangeTr…
Querying with EDM: We have created EDM, DbContext, and entity classes in the previous sections. Here, you will learn the different types of queries an entity framework supports, which is in turn converted into SQL query for the underlaying database.…
Model First development with Entity Framework: In the Model First approach, you create Entities, relationships, and inheritance hierarchies directly on the design surface of EDMX and then generate database from your model. So, in the Model First appr…
DBContext: As you have seen in the previous Create Entity Data Model section, EDM generates the SchoolDBEntities class, which was derived from the System.Data.Entity.DbContext class, as shown below. The class that derives DbContext is called context…
Create Entity Data Model: Here, we are going to create an Entity Data Model (EDM) for SchoolDB database and understand the basic building blocks. Entity Data Model is a model that describes entities and the relationships between them. Let's create fi…
What is Entity Framework? Writing and managing ADO.Net code for data access is a tedious and monotonous job. Microsoft has provided an O/RM framework called "Entity Framework" to automate database related activities for your application. Microso…
