The method of NET5 console program using EF to connect MYSQL database
- 2021-12-04 09:50:41
- OfStack
1. Use nuget to download:
Microsoft.Extensions.Configuration.Json
Pomelo.EntityFrameworkCore.MySql
2. Create a good table in the database:
CREATE TABLE `user2` (
`mid` int NOT NULL AUTO_INCREMENT,
`uname` varchar(45) NOT NULL,
`memo` varchar(200) DEFAULT NULL,
PRIMARY KEY (`mid`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
3. Create a new entity class:
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace ConsoleApp1
{
public class user2
{
[Key] // Primary key
[DatabaseGenerated(DatabaseGeneratedOption.Identity)] // Set self-increment
public int mid { get; set; }
public string uname { get; set; }
public string memo { get; set; }
}
}
4. Create a new json configuration file: appsettings. json, set to always copy.
{
"ConnectionStrings": {
"Default": "Server=127.0.0.1;Database=wdb;charset=utf8;uid=root;pwd=some;"
}
}
5. New DbContext
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using System.IO;
namespace ConsoleApp1
{
public class DefaultDbContext : DbContext
{
private IConfiguration configuration;
public DefaultDbContext()
{
configuration = new ConfigurationBuilder().SetBasePath(Directory.GetCurrentDirectory()).AddJsonFile("appsettings.json").Build();
}
public DbSet<user2> user2 { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
string connStr = configuration.GetConnectionString("Default");
optionsBuilder.UseMySql(connStr, ServerVersion.AutoDetect(connStr),null);
}
}
}
STEP 6 Use
using ConsoleApp1;
using System;
using System.Linq;
namespace Net5ConsoleMySql
{
class Program
{
static void Main(string[] args)
{
try
{
DefaultDbContext context = new DefaultDbContext();
Random rnd = new Random();
string i = rnd.Next(1000, 9000).ToString();
user2 zhangsan = new user2 { uname = " Zhang 3" + i, memo = i };
user2 lisi = new user2 { uname = " Li 4" + i, memo = i };
context.user2.AddRange(zhangsan, lisi);
context.SaveChanges();
var users = context.user2.ToList();
foreach (var user in users)
{
Console.WriteLine($"{user.mid} {user.uname} {user.memo}");
}
}
catch (Exception ex)
{
Console.WriteLine($"EX: {ex.Message} ");
if (ex.InnerException != null)
{
Console.WriteLine($"INNER EX: {ex.InnerException.Message} ");
}
}
Console.WriteLine("Hello World!");
}
}
}