EF Core反向工程

红太狼 2024-03-22 13:28 52阅读 0赞

## 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;

![a1137e422b9c4f59a87b950a870b3e89.png][]

### 项目 ###

新建一个空项目，安装如下三个nuget包

![5b63052bc306446fbd987ec4c505afde.png][]

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

![c7cbd320c04040f2a94d1372aa0e647c.png][]

public partial class Student
        {
            public int Id { get; set; }
            /// <summary>
            /// 班级
            /// </summary>
            public string? Class { get; set; }
            /// <summary>
            /// 姓名
            /// </summary>
            public string? Name { get; set; }
            /// <summary>
            /// 年龄
            /// </summary>
            public int? Age { get; set; }
        }

public partial class studentsContext : DbContext
        {
            public studentsContext()
            {
            }
    
            public studentsContext(DbContextOptions<studentsContext> options)
                : base(options)
            {
            }
    
            public virtual DbSet<Student> 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<Student>(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

![8a8e293d13f442e68d40dbcab94d9930.png][]

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

![61fa24bcbf4a4346bc3f526aea0d75c6.png][]

[a1137e422b9c4f59a87b950a870b3e89.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/5e68bc9d4a0e4724a0a6d3a951e836d0.png
[5b63052bc306446fbd987ec4c505afde.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/2d840aef9716493db90654014581be11.png
[c7cbd320c04040f2a94d1372aa0e647c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/fa211e3d43a94da284b2783f4a783f4b.png
[8a8e293d13f442e68d40dbcab94d9930.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/f08e07ab26d6423a890782a4410b0362.png
[61fa24bcbf4a4346bc3f526aea0d75c6.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/22/3a8f8d2bc2d74219b5d9976d9a5f2e9c.png