[EF Core]数据迁移（二）-白红宇

[EF Core]数据迁移（二）

阅读量：6040 次

发布时间：2019-06-20

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摘要

在实际项目中，大多都需要对业务逻辑以及操作数据库的逻辑进行分成操作，这个时候该如何进行数据的迁移呢？

步骤

上篇文章：

比如，我们将数据上下文放在了Data层。

看一下BlogContext内容如下：

public class BlogContext : DbContext    {        public BlogContext(DbContextOptions options) : base(options)        {        }        public DbSet
     
       Users { set; get; }          }

在appsetting中配置连接字符串

{  "ConnectionStrings": {    "DefaultConnection": "Server=localhost;database=MyBlogDb;uid=root;pwd=abcd;"  },  "Logging": {    "IncludeScopes": false,    "LogLevel": {      "Default": "Warning"    }  }}

在StartUp启动类中，做如下操作：

using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;using Microsoft.AspNetCore.Builder;using Microsoft.AspNetCore.Hosting;using Microsoft.EntityFrameworkCore;using Microsoft.Extensions.Configuration;using Microsoft.Extensions.DependencyInjection;using Wolfy.Blog.Data;namespace Wolfy.Blog{    public class Startup    {        public Startup(IConfiguration configuration)        {            Configuration = configuration;        }        public IConfiguration Configuration { get; }        // This method gets called by the runtime. Use this method to add services to the container.        public void ConfigureServices(IServiceCollection services)        {
                string connStr = Configuration.GetConnectionString("DefaultConnection");            services.AddDbContext
     
      (options => options.UseMySQL(connStr,                opt => opt.MigrationsAssembly("Wolfy.Blog")));            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)        {            if (env.IsDevelopment())            {                app.UseDeveloperExceptionPage();                app.UseBrowserLink();            }            else            {                app.UseExceptionHandler("/Home/Error");            }            app.UseStaticFiles();            app.UseMvc(routes =>            {                routes.MapRoute(                    name: "default",                    template: "{controller=Home}/{action=Index}/{id?}");            });        }    }}

可以看到上面可以指定迁移程序集

//        // 摘要:        //     Configures the assembly where migrations are maintained for this context.        //        // 参数:        //   assemblyName:        //     The name of the assembly.        //        // 返回结果:        //     The same builder instance so that multiple calls can be chained.        public virtual TBuilder MigrationsAssembly([CanBeNullAttribute] string assemblyName);

大概意思是配置数据迁移保持的程序集。