基于EFCore的CodeFirst实战（一）总体介绍

本节目标

1 创建实体类Entity

2 创建数据库操作上下文DbContext

3 数据库迁移

实战内容

基于AspNetCore3.1

数据库：Sqlserver2014

开发工具：Vs2019

解决方案：gitee上Xwy.WebApiDemo

项目：Xwy.Domain

依赖库：Microsoft.EntityFrameworkCore，Microsoft.EntityFrameworkCore.SqlServer，Microsoft.EntityFrameworkCore.Tools，Microsoft.EntityFrameworkCore.Design

代码

 项目结构

依赖项都要安装，两个项目都要

Install-Package Microsoft.EntityFrameworkCore
Install-Package Microsoft.EntityFrameworkCore.SqlServer
Install-Package Microsoft.EntityFrameworkCore.Tools
Install-Package Microsoft.EntityFrameworkCore.Design

一个数据库上下文对象时
add-migration init
update-database

多个数据库上下文对象时
add-migration init -Context VueShopDbContext
update-database -Context VueShopDbContext

数据库上下文类

using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Text;
using Xwy.Domain.Entities;

namespace Xwy.Domain.DbContexts
{
    public class VueShopDbContext:DbContext
    {
        public VueShopDbContext()
        {

        }
        public VueShopDbContext(DbContextOptions<VueShopDbContext> options):base(options)
        {

        }
        // 放入可以使用的数据库对象
        public DbSet<TestRecord> TestRecords { get; set; }
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                optionsBuilder.UseSqlServer("Data Source=.;database=VueShopDb;uid=sa;pwd=123456");
                //optionsBuilder.UseSqlServer("Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=TestDB;Data Source=.");//数据库连接字符串，其中TestDB是数据库名称
            }
        }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<TestRecord>().ToTable("TestRecords","xwy");
            base.OnModelCreating(modelBuilder);
        }
    }
}

实体类

using System;
using System.Collections.Generic;
using System.Text;

namespace Xwy.Domain.Entities
{
    public class TestRecord
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Title { get; set; }

    }
}

启动项目配置代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.OpenApi.Models;
using Xwy.Domain.DbContexts;

namespace Xwy.WebApiDemo
{
    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)
        {
            services.AddDbContext<ClothersMallDbContext>(m=> { 
                
            });
            services.AddSwaggerGen(m => 
            {
                m.SwaggerDoc("v1",new OpenApiInfo() { Title="swaggertest",Version="v1"});
            });
            services.AddCors(m => m.AddPolicy("any", a => a.AllowAnyOrigin().AllowAnyMethod().AllowAnyHeader()));
            services.AddControllers();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseSwagger();
            app.UseCors();
            app.UseSwaggerUI(m=> {
                m.SwaggerEndpoint("/swagger/v1/swagger.json","swaggertest");

            });

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}