Method Name Return Type Description Add Added entity type Adds the given entity to the context the Added state. When the changes are being saved, the entities in the Added states are inserted into the database. After the changes are saved, t…
EF自己包括看视频,看MSDN零零散散的学了一点皮毛,这次打算系统学习一下EF.我将会使用VS2012来学习这个EF基础系列. 现在看看EF的历史吧: EF版本 相关版本特性介绍 EF3.5 基于数据库优先的模式的基础ORM框架(Basic O/RM support with Database First approach.) EF4.0 支持简单传统CLR对象(Plain old CLR Object),懒加载, 提高了可测试性,可以自定义代码的生成,支持ModeFirst: (POCO Su…
好久没更新EF这个系列了,现在又重新开始. 这次学习,开放式并发.首先拿出数据库脚本: 说明一下,这个数据库脚本是之前的章节中稍作修改的: USE [SchoolDB] GO /****** Object: Table [dbo].[Student] Script Date: 11/30/2015 21:42:07 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[Student]( [Stu…
原文地址:http://www.entityframeworktutorial.net/EntityFramework-Architecture.aspx 下面的图形,展示了EF的总体架构: 让我们来分别看看,每个组件都是啥吧: EDM(Entity Data Model)[实体数据模型]:EDM(实体数据模型)包含三个主要的部分----概念模型,映射关系以及存储模型. Conceptual Model [概念模型]:概念模型包含模型类以及他们之间的关系.这个是和你的数据库表设计是独立开的. S…
原文链接:http://www.entityframeworktutorial.net/basics/how-entity-framework-works.aspx 这里,你将会大概了解到EF是怎么工作的. Entity Framework API(EF 6和EF Core),可以将领域类映射到数据库中.将LINQ 语句转化为SQL.在实体整个生命周期内,跟踪实体的改变,并且保存改变到数据库中. 实体数据模型(Entity Data Model) EF API 的首要任务就是构建实体数据模型.实…
Entity Framework 5.0 API是分布在两个地方:NuGet和.NET Framework中,这个.NET framework 4.0/4.5包含EF核心的API,然而通过NuGet包获取的EntityFramework.dll包含EF 5.0特别的特性:EF6.0中不是分开的: Entity Framework 5.0 API was distributed in two places, in NuGet package and in .NET framework. The .…
EF产生的背景: 编写ADO.NET访问数据的代码,是沉闷而枯燥的,所以微软提供了一个对象关系映射框架(我们称之为EF),通过EF可以自动帮助我们的程序自动生成相关数据库. 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 autom…
Before we work on CRUD operation (Create, Read, Update, Delete), it's important to understand the entity lifecycle and how it is being managed by the EntityFramework. During an entity's lifetime, each entity has an entity state based on the operation…
DBContext: As you have seen in the previous Create Entity Data Model section, EDM generates the SchoolDBEntities class, which was derived from theSystem.Data.Entity.DbContext class, as shown below. The class that derives DbContext is called context c…
We have created our first Entity Data Model for School database in the previous section. The visual designer of EDM does not display all the objects it creats. It only display entities which are mapped to the database tables and views. Model Browser …
我们来看看EF的框架设计吧: The following figure shows the overall architecture of the Entity Framework. Let us now look at the components of the architecture individually: EDM (Entity Data Model): EDM consists of three main parts - Conceptual model, Mapping and…
We created EDM for existing database in the previous section. As you have learned in the previous section that EDM contains entities for each table in the database. There are two types of Entities in Entity Framework 5.0/6.0: POCO entity and dynamic…
Here, you will learn how entity framework manages the relationships between entities. Entity framework supports three types of relationships, same as database: 1) One to One 2) One to Many, and 3) Many to Many. We have created an Entity Data Model fo…
EF支持三种类型的查询: 1.LINQ to Entities 2.Entity SQL 3.Native SQL 1.LINQ to Entities LINQ Method syntax: using (var context = new SchoolDBEntities1()) { //使用Linq to Entities var myQuery = context.Students.Where(s => s.StudentName == "张三"); var studen…
现在我要来为上面一节末尾给出的数据库(SchoolDB)创建实体数据模型: SchoolDB数据库的脚本我已经写好了,如下: USE master GO IF EXISTS(SELECT * FROM sys.sysdatabases WHERE name='SchoolDB') DROP DATABASE SchoolDB; GO CREATE DATABASE SchoolDB GO USE SchoolDB; GO --创建Standard表 IF EXISTS (SELECT * FRO…
一. memory存储引擎 memoery存储引擎是在内存中来创建表,每个memory表只实际对应一个磁盘文件格式是.frm. 该引擎的表访问非常得快,因为数据是放在内存中,且默认是hash索引,但服务关闭,表中的数据就会丢失掉. -- 下面创建一个memory表,并从city表获得记录 CREATE TABLE tab_memory ENGINE=MEMORY SELECT city_id,country_id FROM city GROUP BY city_id -- 给momory 表…
原创作品,可以转载,但是请标注出处地址:https://www.cnblogs.com/V1haoge/p/10748925.html 一.概述 Collector是专门用来作为Stream的collect方法的参数的. public interface Stream<T> extends BaseStream<T, Stream<T>> { <R, A> R collect(Collector<? super T, A, R> collecto…
