.NET Core Entity使用Entity Framework Core链接数据库-白红宇

.NET Core Entity使用Entity Framework Core链接数据库

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发布时间：2019-06-19

本文共 3396 字，大约阅读时间需要 11 分钟。

首先安装Nuget包

Install-package Microsoft.EntityFrameworkCoreInstall-package Microsoft.EntityFrameworkCore.SqlServer

Micorsoft.EntityFrameworkCore：EF框架的核心包

Micorsoft.EntityFrameworkCore.SqlServer:针对SqlServer数据库的扩展

其次设置（appsettings.json）配置文件的数据连接字符串

"ConnectionStrings": {    "SqlServer": "Data Source=localhost;Initial Catalog=testingdb;Integrated Security=False;Persist Security Info=False;User ID=sa;Password=password"  }

创建实体（province）

namespace MicroCore{    using System.ComponentModel.DataAnnotations;    using System.ComponentModel.DataAnnotations.Schema;    [Table("dt_province")]    public class province    {        [Key]        ///         /// 自动        /// 
        public int id { set; get; }        ///         /// 当前标识        /// 
        public string code { set; get; }        ///         /// 名称        /// 
        public string name { set; get; }    }}

方法一、通过配置链接数据库

1、创建Entity Framework Core配置

namespace MicroCore{    using Microsoft.EntityFrameworkCore;    public class EFContext : DbContext    {        public EFContext(DbContextOptions
     
       options) : base(options)        {        }        protected override void OnModelCreating(ModelBuilder modelBuilder)        {            base.OnModelCreating(modelBuilder);            modelBuilder.Entity
      
       (entity =>            {                entity.ToTable("dt_province");                entity.HasKey(a => a.id);            });        }        public DbSet
       
         province { get; set; }    }}

2、Startup 启动注册链接

public void ConfigureServices(IServiceCollection services){    services.AddMvc();    services.AddApplicationInsightsTelemetry(Configuration);    services.AddEntityFrameworkSqlServer().AddDbContext
     
      (options => options.UseSqlServer(Configuration.GetConnectionString("SqlServer")));}

3、Index.cshtml.cs调用数据

namespace MicroCore.Pages{    public class IndexModel : PageModel    {        private readonly EFContext db;        public IndexModel(EFContext db)        {            this.db = db;        }        public void OnGet()        {            var result = db.province.Where(p => p.id == 1).ToList();        }    }}

方法二、自定义配置链接数据库

1、创建Entity Framework Core配置

namespace MicroCore{    using Microsoft.EntityFrameworkCore;    public class EFContext : DbContext    {        public static string ConnectionString { get; set; }        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)        {                        optionsBuilder.UseSqlServer(ConnectionString, b => b.UseRowNumberForPaging());        }        protected override void OnModelCreating(ModelBuilder modelBuilder)        {            base.OnModelCreating(modelBuilder);            modelBuilder.Entity
     
      (entity =>            {                entity.ToTable("dt_province");                entity.HasKey(a => a.id);            });        }        public DbSet
      
        province { get; set; }    }}

2、Startup 取得配置链接

public void ConfigureServices(IServiceCollection services){    services.AddMvc();    EFContext.ConnectionString = Configuration.GetConnectionString("SqlServer");}

3、Index.cshtml.cs调用数据

namespace MicroCore.Pages{    public class IndexModel : PageModel    {        public void OnGet()        {            EFContext db = new EFContext();                     var result = db.province.Where(p => p.id == 3).ToList();        }    }}