EF Core反向工程

数据库准备

在数据库新建一个库students，然后创建如下一个表，这里演示使用的是MySQL

CREATE TABLE `student` (
  `id` int NOT NULL,
  `class` varchar(255) DEFAULT NULL COMMENT '班级',
  `name` varchar(255) DEFAULT NULL COMMENT '姓名',
  `age` int DEFAULT NULL COMMENT '年龄',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

 项目

新建一个空项目，安装如下三个nuget包

 打开终端，到当前项目路径下，输入如下命令

 dotnet ef dbcontext scaffold "server=127.0.0.1;uid=root;pwd=123456;database=students" Pomelo.EntityFrameworkCore.MySql

项目中就会自动创建这两个类

 public partial class Student
    {
        public int Id { get; set; }
        /// 

        /// 班级
        /// 
        public string? Class { get; set; }
        /// 

        /// 姓名
        /// 
        public string? Name { get; set; }
        /// 

        /// 年龄
        /// 
        public int? Age { get; set; }
    }

 

    public partial class studentsContext : DbContext
    {
        public studentsContext()
        {
        }

        public studentsContext(DbContextOptions options)
            : base(options)
        {
        }

        public virtual DbSet Students { get; set; } = null!;

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
#warning To protect potentially sensitive information in your connection string, you should move it out of source code. You can avoid scaffolding the connection string by using the Name= syntax to read it from configuration - see https://go.microsoft.com/fwlink/?linkid=2131148. For more guidance on storing connection strings, see http://go.microsoft.com/fwlink/?LinkId=723263.
                optionsBuilder.UseMySql("server=127.0.0.1;uid=root;pwd=123456;database=students", Microsoft.EntityFrameworkCore.ServerVersion.Parse("8.0.33-mysql"));
            }
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.UseCollation("utf8mb4_0900_ai_ci")
                .HasCharSet("utf8mb4");

            modelBuilder.Entity(entity =>
            {
                entity.ToTable("student");

                entity.Property(e => e.Id)
                    .ValueGeneratedNever()
                    .HasColumnName("id");

                entity.Property(e => e.Age)
                    .HasColumnName("age")
                    .HasComment("年龄");

                entity.Property(e => e.Class)
                    .HasMaxLength(255)
                    .HasColumnName("class")
                    .HasComment("班级");

                entity.Property(e => e.Name)
                    .HasMaxLength(255)
                    .HasColumnName("name")
                    .HasComment("姓名");
            });

            OnModelCreatingPartial(modelBuilder);
        }

        partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
    }

然后就可以查询数据库中的数据了

在默认情况下，生成的类都是放根目录下的，所以还需要优化一下，在刚刚命令后面加上--context-dir 和--output-dir 来指定存放的文件夹

dotnet ef dbcontext scaffold "server=127.0.0.1;uid=root;pwd=123456;database=students" Pomelo.EntityFrameworkCore.MySql --context-dir Data --output-dir Entities