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asp.net core 使用EF7 Code First 创建数据库,同时使用命令创建数据库

2016-05-19 00:41 501 查看
1.首先下载vs2015的Asp.Net Core(RC2)的插件工具(https://www.microsoft.com/net/core#windows)
2.创建一个asp.net Core的项目,这里我创建一个最简单的项目,就是一个console,在这个基础上我准备一步一步搭建一个Asp.Net Core的项目



3.添加相关的依赖(mvc的依赖和EF的依赖)在projecr.json中:

{
"dependencies": {
"Microsoft.NETCore.App": {
"version": "1.0.0-rc2-3002702",
"type": "platform"
},
"Microsoft.AspNetCore.Server.IISIntegration": "1.0.0-rc2-final",
"Microsoft.AspNetCore.Server.Kestrel": "1.0.0-rc2-final",
"Microsoft.AspNetCore.StaticFiles": "1.0.0-rc2-final",
"Microsoft.AspNetCore.Mvc": "1.0.0-rc2-final",
"Microsoft.AspNetCore.Razor.Tools": {
"version": "1.0.0-preview1-final",
"type": "build"
},
"Npgsql.EntityFrameworkCore.PostgreSQL": "1.0.0-rc2-release1",
"Microsoft.EntityFrameworkCore.Tools": {
"version": "1.0.0-preview1-final",
"type": "build"
},
"Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0-rc2-final",
"Microsoft.Extensions.Configuration.Json": "1.0.0-rc2-final",
"Microsoft.Extensions.Logging": "1.0.0-rc2-final",
"Microsoft.Extensions.Logging.Console": "1.0.0-rc2-final",
"Microsoft.Extensions.Logging.Debug": "1.0.0-rc2-final"
},

"tools": {
"Microsoft.AspNetCore.Razor.Tools": {
"version": "1.0.0-preview1-final",
"imports": "portable-net45+win8+dnxcore50"
},
"Microsoft.AspNetCore.Server.IISIntegration.Tools": {
"version": "1.0.0-preview1-final",
"imports": "portable-net45+win8+dnxcore50"
},
"Microsoft.EntityFrameworkCore.Tools": {
"version": "1.0.0-preview1-final",
"imports": [
"portable-net45+win8+dnxcore50",
"portable-net45+win8"
]
}
},

"frameworks": {
"netcoreapp1.0": {
"imports": [
"dotnet5.6",
"dnxcore50",
"portable-net45+win8"
]
}
},

"buildOptions": {
"emitEntryPoint": true,
"preserveCompilationContext": true
},

"runtimeOptions": {
"gcServer": true
},

"publishOptions": {
"include": [
"wwwroot",
"web.config"
]
},

"scripts": {
"postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
}
}


4。在Startup.cs 文件中做如下修改:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;

namespace SmBlog
{
public class Startup
{

public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);

if (env.IsDevelopment())
{
}

builder.AddEnvironmentVariables();
Configuration = builder.Build();
}

public IConfigurationRoot Configuration { get; }

public void ConfigureServices(IServiceCollection services)
{
services.AddMvc();
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{

loggerFactory.AddConsole(Configuration.GetSection("Logging"));
loggerFactory.AddDebug();

app.UseStaticFiles();

app.UseMvc(routes =>
{
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
}
);

}
}
}


现在并没有添加Ef的服务。

5.新建一个appsettings.json 文件用于项目相关配置,在Startup.cs中的log的配置,以及后来的EF数据库的配置都在这个文件中。

{
"ConnectionStrings": {
"PostgreSql": "User ID=postgres;Password=123456;Host=localhost;Port=5432;Database=smbloh"
},
"Logging": {
"IncludeScopes": false,
"LogLevel": {
"Default": "Debug",
"System": "Information",
"Microsoft": "Information"
}
}
}


6.依照MVC5中的项目目录结构创建如Controllers 和Views和Models文件如下图所示,新建一个HomeController 和Index Action和Index的视图,用于测试。



7.用过dotnet的方式运行(dotnet 相当于之前的dnx) 看到这个结果说明mvc6项目搭建完成



8.开始Ef的操作。在Models中新建一个实体Article简单的给他三个字段

public class Article
{
public int Id { set; get; }

public string Title { set; get; }

public string Description { set; get; }
}


9.在Models中新建一个SMContext(ef上下文对象)代码如下:

public class SMContext : DbContext
{
public SMContext(DbContextOptions option) : base(option)
{

}

public DbSet<Article> Articles { set; get; }

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
}

}


10.修改Startup.cs 文件。增加对Ef的支持:代码如下

public void ConfigureServices(IServiceCollection services)
{
services.AddMvc();

services.AddDbContext<SMContext>(option => option.UseNpgsql(Configuration.GetConnectionString("PostgreSql")));

}


11.为了初始化数据库,在此新建一个SampleData类,在项目启动的时候,调用此类,进行数据库的初始化。代码如下:

namespace SmBlog.Models
{
public class SampleData
{
public async static Task InitDB(IServiceProvider service)
{
var db = service.GetService<SMContext>();

if (db.Database != null && db.Database.EnsureCreated())
{

Article article = new Article
{
Title = "test",
Description = "SMBlog Test"
};

db.Articles.Add(article);
await db.SaveChangesAsync();
}
}
}
}


这个地方比较灵活,我们初始化创建数据库的时候可以插入一条数据,也可以不插入。我在这个地方插入了一条文章的数据。当然系统中有用户,插入管理员是比较适当的操作的。

12.再次修改Startup文件 调用SampleData 在加载项目的时候创建数据库 并初始化。代码如下:

public async void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{

loggerFactory.AddConsole(Configuration.GetSection("Logging"));
loggerFactory.AddDebug();

app.UseStaticFiles();

app.UseMvc(routes =>
{
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
}
);

await SampleData.InitDB(app.ApplicationServices);
}


13.再次启动项目,我的数据已经创建成功,并且插入一条数据。如图:



14.数据库迁移 。当我们增加一个User实体,并且修改了Article的实体,现在要进行数据库的迁移,不是简单的把数据库删除重新建立。要保证原有的数据不变,修改数据库结构。

增加的User实体如下:

public class User
{
public int Id { set; get; }

public string UserName { set; get; }

public string Password { set; get; }
}


修改后的Article实体如下,加了个Label的字段

public class Article
{
public int Id { set; get; }

public string Title { set; get; }

public string Description { set; get; }

public string Label { set; get; }
}


在SMContext文件中,增加User的DbConetxt;

如下代码:

public DbSet<User> Users { set; get; }


15.在vs的PM命令输入 Add-Migration newBook



成功后会在项目中产生一个Migrations文件夹。里面有个快照文件和一个迁移的文件。在此不扩展了。

在执行命令: Update-Database newBook 发现报错了



问题解决,不用SampleData来初始化数据库,用 Add-Migration init Update-Database init 来初始化数据库。

注:也可以在cmd控制台输入命令来实现code first

首先打开cmd 切换到项目的project.json 文件所在文件。执行如下命令

dotnet ef migrations add FirstMigration
dotnet ef database update
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