一次数据迁移的记录 首先在vs工具里面使用打开程序包管理器控制台 在控制台上面选择程序集为数据访问层 注意配置生成app里面的连接字符串 在控制台输入 Enable-Migrations 会自动生成一个migrations文件夹 添加迁移 名字为addactionviewid Add-Migration addactionviewid 执行完会自动生成一个类 里面有部分已知的数据库和当前项目里面的实体的不同项 可根据需要袭击修改 修改好并确定之后 执行 Update-Database 可在Upd…

前言 紧接着前面一篇博文Entity Framework CodeFirst尝试. 我们知道无论是“Database First”还是“Model First”当模型发生改变了都可以通过Visual Studio设计视图进行更新,那么对于Code First如何更新已有的模型呢?今天我们简单介绍一下Entity Framework的数据迁移功能. Entity Framework配置 当我们对项目进行Entity Framework进行安装引用的时候,同时生成了两个配置文件 packages.c…

警告:这是一个入门级日志,如果你很了解CodeFirst,那请绕道 背景:这篇日志记录我使用Entity FrameWork CodeFirst时出现的错误和解决问题的过程,虽然有点曲折……勿喷 备注:这确实算是Entity FrameWork CodeFirst的问题个人也不知道应该给文章加什么样的关键字和标题,方便各位朋友搜索 一.问题出现 当我参考 洞庭夕照 博客 ASP.NET MVC5 网站开发实践 - 概述 按照代码一点点尝试CodeFirst(虽然这不是一个针对CodeFirst的…

上一篇 第二篇:Entity Framework CodeFirst & Model 映射 主要介绍以Fluent API来实作EntityFramework CodeFirst,得到了大家一些支持,其中就有一位同学就提出.熟悉了EntityFramework CodeFirst 原理,就可以用微软的工具来生产代码.是的,今天就来讲一下,由微软EntityFramework小组开发的为EntityFramework CodeFirst Visual Studio小插件 “Entity Frame…

ADO.NET Entity Framework CodeFirst 如何输出日志(EF4.3) 用的EFProviderWrappers ,这个组件好久没有更新了,对于SQL执行日志的解决方案的需求是杠杠的,今天给大家介绍一个更好的组件Clutch.Diagnostics.EntityFramework,可以通过Nuget 获取: 这个框架定义了一个接口 IDbTracingListener: namespace Clutch.Diagnostics.EntityFramework { pub…

前一篇 第一篇:Entity Framework 简介 我有讲到,ORM 最关键的 Mapping,也提到了最早实现Mapping的技术,就是 特性 + 反射,那Entity Framework 实现Mapping 又是怎样的呢? EntityFramework 实现Mapping 有两种方式. 1. 数据注解(DataAnnotations) 2. Fluent API 一. 数据注解,这种方式,就是在实体和属性加上一些EntityFramework 定义好的一些特性,然后EntityFram…

Migration in Code-First: Entity framework Code-First had different database initialization strategies prior to EF 4.3 like CreateDatabaseIfNotExists, DropCreateDatabaseIfModelChanges, or DropCreateDatabaseAlways. However, there were some problems wit…

Cascade Delete in Entity Framework Code-First: Cascade delete automatically deletes dependent records or set null to foreignkey properties when the principal record is deleted. Cascade delete is enabled by default in Entity Framework for all types of…

Setup Development Environment for EF Code-First: Let's setup the development environment for Code-First before starting on it. Install the following tools to work with Entity Framework Code-First: .NET Framework 4.5 Visual Studio 2012 MS SQL Server 2…

Entity Framework Code-First: Learn Entity Framework Code-First in simple step-by-step tutorials. These tutorials cover all the features of Entity Framework Code-First starting with the basics of code-first, DB migration, configuring one-to-one, one-t…

Entity Framework Codefirst的配置步骤: (1) 安装命令: install-package entityframework (2) 创建实体类,注意virtual关键字在导航属性中的用法 (3) 创建DbContext类,为每个entity set创建一个DbSet:    指定一个连接字符串构造函数中的 base("AccountContext") .    设置表的单数形式 public class AccountContext:DbContext { p…

Automated Migration: Entity framework 4.3 has introduced Automated Migration so that you don't have to process database migration manually in the code file, for each change you make in your domain classes. You just need to run a command in Package Ma…

以下是书<Programming Entity Framework Code First>的学习整理,主要是一个整体梳理. 一.模型属性映射约定 1.通过 System.Component  Model.DataAnnotations 来配置 class AnimalType { public int Id { get; set; } [Required] public string TypeName { get; set; } } 意味着TypeName在数据库中的字段为not null.第…

TOPIC about_EntityFramework SHORT DESCRIPTION Provides information about Entity Framework commands. LONG DESCRIPTION This topic describes the Entity Framework commands. Entity Framework is Microsoft's recommended data access technology for new applic…

Entity Framework Power Tools: Entity Framework Power Tools (currently in beta 3) has been released. EF Power Tools is useful mainly in reverse engineering and generating read-only entity data model for code-first. Download and install Power Tools fro…

Code-First from an Existing Database: Here, you will learn how to generate code-first context and entity classes for an existing database. Entity Framework provides an easy way to use code-first approach for an existing database. It will create entit…

DataAnnotations - StringLength Attribute: StringLength attribute can be applied to a string type property of a class. EF Code-First will set the size of a column as specified in StringLength attribute. Note that it can also be used with ASP.Net MVC a…

DataAnnotations - MaxLength Attribute: MaxLength attribute can be applied to a string or array type property of a domain class. EF Code First will set the size of a column as specified in MaxLength attribute. Note that it can also be used with ASP.Ne…

Inheritance Strategy in Code-First: We have seen in the Code First Conventions section that it creates database tables for each concrete domain class. However, You can design your domain classes using inheritance. Object-oriented techniques include "…

Code First Conventions: We have seen how EF Code-First creates DB tables from domain classes in the previous section. Here, we will learn about default Code-First conventions. What is Convention? Convention is a set of default rules to automatically…

Simple Code First Example: Let's assume that we want to create a simple application for XYZ School. Users of this School application should be able to add or update Students, Standard (Grade), Teacher, and Course information. Instead of designing dat…

What is Code-First?: Entity Framework introduced Code-First approach from Entity Framework 4.1. Code-First is mainly useful in Domain Driven Design. With the Code-First approach, you can focus on the domain design and start creating classes as per yo…

前言 Code First模式我们称之为“代码优先”模式,是从EF4.1开始新建加入的功能.使用Code First模式进行EF开发时开发人员只需要编写对应的数据类(其实就是领域模型的实现过程),然后自动生成数据库.这样设计的好处在于我们可以针对概念模型进行所有数据操作而不必关系数据的存储关系,使我们可以更加自然的采用面向对象的方式进行面向数据的应用程序开发. 从某种角度来看,其实“Code First”和“Model First”区别并不是太明显,只是它不借助于实体数据模型设计器,而是直接通过…

Code-based Migration: Code-based migration is useful when you want more control on the migration, i.e. set default value of the column, etc. Code-First has two commands for code based migration: Add-migration: It will scaffold the next migration for…

Database Initialization Strategies in Code-First: You already created a database after running your Code-First application the first time, but what about the second time onwards?? Will it create a new database every time you run the application? What…

Move Configurations to Separate Class in Code-First: By now, we have configured all the domain classes in OnModelCreating method in the previous sections. When you have a large number of domain classes, then configuring every class in OnModelCreating…

Configure Many-to-Many relationship: Here, we will learn how to configure Many-to-Many relationship between the Student and Course entity classes. Student can join multiple courses and multiple students can join one course. Visit Entity Relationship …

Configure One-to-Many Relationship: Here, we will learn how to configure One-to-Many relationship between two entities in code-first. Take an example of Student and Standard (grade) entities where one Standard can include many Students. So the relati…

Configure One-to-Zero-or-One Relationship: Here, we will configure One-to-Zero-or-One relationship between two entities, e.g. Entity1 can be associated with zero or only one instance of Entity2. Take an example of the following Student and StudentAdd…

Property Mappings using Fluent API: Here, we will learn how to configure properties of an entity class using Fluent API. We will use the following Student and Standard domain classes of our school application. public class Student { public Student()…