Net8 EFCore Mysql 连接-编程知识

Net8 EFCore Mysql 连接

一、安装插件

Pomelo.EntityFrameworkCore.MySq (这里要选8.0.0以上版本低版本不支持.net8)

二、配置数据库连接串

appsettings.json 中配置数据库连接串

"ConnectionStrings": {"Connection": "server=172.18.2.183;port=3306;database=students;uid=root;pwd=123456;CharSet=utf8"
}

三、添加实体类Student和数据库上下文

新建 Entities 目录，在，根据表及字段，在目录下新建 Student 实体类，在类上加 [Table("student")] 表名、属性上加[Column("id")] 字段名等与表对应，代码如下：

using System.ComponentModel.DataAnnotations.Schema;namespace Snai.Mysql.Entities
{[Table("students")]public class Student{[Column("id")]public int ID { get; set; }[Column("name")]public string Name { get; set; }}
}

在根目录下加上 DataAccess 目录做为数据库操作目录，在该目录下加上 Base 目录做数据库上下文目录

在 Base 目录下新建 SqlContext 上下文类，继承 DbContext 类，通过构造函数注入数据库连接，添加 DbSet<Student> 实体属性，代码如下：

using Microsoft.EntityFrameworkCore;
using Snai.Mysql.Entities;namespace Server.DataAccess.Base
{public class SqlContext : DbContext{public SqlContext(DbContextOptions<SqlContext> options): base(options){ }public DbSet<Student> Student { get; set; }}
}

在DataAccess目录下创建Interface和Implement文件夹分别为数据库对应数据的接口和实现。

接口定义：

using Server.Mysql.Entities;namespace Server.DataAccess.Interface
{public interface IStudentDao{//插入数据bool CreateStudent(Student student);//取全部记录IEnumerable<Student> GetStudents();//取某id记录Student GetStudentByID(int id);//根据id更新整条记录bool UpdateStudent(Student student);//根据id更新名称bool UpdateNameByID(int id, string name);//根据id删掉记录bool DeleteStudentByID(int id);}
}

实现:

using Server.DataAccess.Base;
using Server.DataAccess.Interface;
using Server.Mysql.Entities;namespace Server.DataAccess.Implement
{public class StudentDao : IStudentDao{private SqlContext _context;public StudentDao(SqlContext context){_context = context;}//插入数据public bool CreateStudent(Student student){_context.Student.Add(student);return _context.SaveChanges() > 0;}//取全部记录public IEnumerable<Student> GetStudents(){return _context.Student.ToList();}//取某id记录public Student? GetStudentByID(int id){return _context.Student.SingleOrDefault(s => s.ID == id);}//根据id更新整条记录public bool UpdateStudent(Student student){_context.Student.Update(student);return _context.SaveChanges() > 0;}//根据id更新名称public bool UpdateNameByID(int id, string name){var state = false;var student = _context.Student.SingleOrDefault(s => s.ID == id);if (student != null){student.Name = name;state = _context.SaveChanges() > 0;}return state;}//根据id删掉记录public bool DeleteStudentByID(int id){var student = _context.Student.SingleOrDefault(s => s.ID == id);_context.Student.Remove(student);return _context.SaveChanges() > 0;}}
}

依赖注入

在Program.cs中写入

string? sqlConnection = builder.Configuration.GetConnectionString("Connection");
if (sqlConnection != null) 
{builder.Services.AddDbContext<SqlContext>(options =>{var serverVersion = ServerVersion.AutoDetect(sqlConnection);  //mysql版本: {8.2.0-mysql}options.UseMySql(sqlConnection, serverVersion);});
}
builder.Services.AddScoped<IStudentDao, StudentDao>(); //对于同一个请求返回同一个实例

设计表

Controller调用

private IStudentDao _iStudentDao;public TestController(IStudentDao iStudentDao)  //构造函数中添加
{_iStudentDao = iStudentDao;
}//调用测试方法创建
public void TestCreate()
{Student student = new Student();student.ID = 1;student.Name = "在下没有钱";_iStudentDao.CreateStudent(student);
}

运行结果：