.NET5控制檯程式使用EF連線MYSQL

1.使用nuget下載：

Microsoft.Extensions.Configuration.Json

Pomelo.EntityFrameworkCore.MySql

2.資料庫中建立好表：

  1. CREATE TABLE `user2` (
  2.   `mid` int NOT NULL AUTO_INCREMENT,
  3.   `uname` varchar(45) NOT NULL,
  4.   `memo` varchar(200) DEFAULT NULL,
  5.   PRIMARY KEY (`mid`)
  6. ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

3.新建實體類：

  1. using System.ComponentModel.DataAnnotations;
  2. using System.ComponentModel.DataAnnotations.Schema;
  3.  
  4. namespace ConsoleApp1
  5. {
  6.     public class user2
  7.     {
  8.         [Key] //主鍵
  9.         [DatabaseGenerated(DatabaseGeneratedOption.Identity)]  //設定自增
  10.         public int mid { get; set; }
  11.         public string uname { get; set; }
  12.  
  13.         public string memo { get; set; }
  14.     }
  15. }

4.新建一個json配置檔案：appsettings.json，設定為始終複製。

  1. {
  2.   "ConnectionStrings": {
  3.     "Default": "Server=127.0.0.1;Database=wdb;charset=utf8;uid=root;pwd=some;"
  4.   }
  5. }

5.新建DbContext

  1. using Microsoft.EntityFrameworkCore;
  2. using Microsoft.Extensions.Configuration;
  3. using System.IO;
  4.  
  5. namespace ConsoleApp1
  6. {
  7.     public class DefaultDbContext : DbContext
  8.     {          
  9.  
  10.         private IConfiguration configuration;
  11.  
  12.         public DefaultDbContext()
  13.         {
  14.             configuration = new ConfigurationBuilder().SetBasePath(Directory.GetCurrentDirectory()).AddJsonFile("appsettings.json").Build();
  15.         }
  16.  
  17.         public DbSet<user2> user2 { get; set; }
  18.  
  19.         protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
  20.         {
  21.             string connStr = configuration.GetConnectionString("Default");
  22.             optionsBuilder.UseMySql(connStr, ServerVersion.AutoDetect(connStr),null);
  23.         }
  24.     }
  25. }

6.使用

  1. using ConsoleApp1;
  2. using System;
  3. using System.Linq;
  4.  
  5. namespace Net5ConsoleMySql
  6. {
  7.     class Program
  8.     {
  9.         static void Main(string[] args)
  10.         {
  11.             try
  12.             {
  13.                 DefaultDbContext context = new DefaultDbContext();
  14.                 Random rnd = new Random();
  15.                 string i = rnd.Next(1000, 9000).ToString();
  16.                 user2 zhangsan = new user2 { uname = "張三" + i, memo = i };
  17.                 user2 lisi = new user2 { uname = "李四" + i, memo = i };
  18.                 context.user2.AddRange(zhangsan, lisi);
  19.                 context.SaveChanges();
  20.  
  21.                 var users = context.user2.ToList();
  22.                 foreach (var user in users)
  23.                 {
  24.                     Console.WriteLine($"{user.mid} {user.uname} {user.memo}");
  25.                 }
  26.             }
  27.             catch (Exception ex)
  28.             {
  29.                 Console.WriteLine($"EX: {ex.Message}  ");
  30.                 if (ex.InnerException != null)
  31.                 {
  32.                     Console.WriteLine($"INNER EX: {ex.InnerException.Message}  ");
  33.                 }
  34.             }
  35.             Console.WriteLine("Hello World!");
  36.         }
  37.     }
  38. }