我正在使用 MySql 数据库开发毛伊岛应用程序。当我第一次与数据库交互时，出现异常： “ System.Exception：‘字段列表’中的未知列‘s.ManagerGroup_id’” 我正在使用 ORM 标签。
[Table("ManagerGroups")]
public class ManagerGroup
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ManagerGroup_id { get; set; }
[Required]
[Column(TypeName = "char(100)")]
public required string Name { get; set; }
public List<Manager> Managers { get; set;} = new List<Manager>();
public List<Staff> AssignedStaff { get; set;} = new List<Staff>();
}
public class MyDbContext : DbContext
{
public MyDbContext(DbContextOptions<MyDbContext> options) : base(options)
{
}
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
// Configure logging directly within OnConfiguring
var loggerFactory = LoggerFactory.Create(builder =>
{
builder.AddConsole().SetMinimumLevel(LogLevel.Information); // Add console logging provider
});
optionsBuilder.UseLoggerFactory(loggerFactory); // Configure logging
var logger = loggerFactory.CreateLogger<MyDbContext>();
logger.LogWarning("Logger Ready!");
}
// DbSet properties for your database entities
//public DbSet<MyEntity> MyEntities { get; set; }
public DbSet<User> Users { get; set; }
public DbSet<Manager> Managers { get; set; }
public DbSet<Staff> Staff { get; set; }
public DbSet<SoS_AnswerSheet> SoS_AnswerSheets { get; set; }
public DbSet<Staff_SoSList> Staff_SoSLists { get; set; }
public DbSet<ManagerGroup> ManagerGroups { get; set; }
// Add more DbSet properties for other entities if needed
//Junction Table config for composite keys
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<Staff_SoSList>()
.HasKey(e => new { e.ManagerGroup_id, e.Staff_id });
//SoS_AnswerSheet Enum mapping to int
#region SoS_AnswerSheet Enum mapping
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer1)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer2)
.HasConversion<int>();
// Configure other enum properties similarly
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer3)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer4)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer5)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer6)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer7)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer8)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer9)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer10)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer11)
.HasConversion<int>();
modelBuilder.Entity<SoS_AnswerSheet>()
.Property(e => e.Answer12)
.HasConversion<int>();
#endregion
}
}
我检查了数据库中的所有表，名称正确且与应用程序中的表匹配。 我尝试通过记录 sql 查询来解决这个问题，但我无法让记录器工作。 请考虑我是数据库新手。如果需要的话，很乐意提供更多信息。
错误日志：
Microsoft.EntityFrameworkCore.Database.Command: Error: Failed executing DbCommand (27ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT `u`.`User_id`, `u`.`CreatedAt`, `u`.`First_name`, `u`.`Last_name`, `m`.`Manager_id`, `s`.`ManagerGroup_id`, `s`.`staff_id`, CASE
WHEN `s`.`User_id` IS NOT NULL THEN 'Staff'
WHEN `m`.`User_id` IS NOT NULL THEN 'Manager'
END AS `Discriminator`
FROM `Users` AS `u`
LEFT JOIN `Managers` AS `m` ON `u`.`User_id` = `m`.`User_id`
LEFT JOIN `Staff` AS `s` ON `u`.`User_id` = `s`.`User_id`
'WaiterEval.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\8.0.4\System.Diagnostics.StackTrace.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'WaiterEval.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\8.0.4\System.Reflection.Metadata.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'WaiterEval.exe' (CoreCLR: clrhost): Loaded 'C:\Program Files\dotnet\shared\Microsoft.NETCore.App\8.0.4\System.IO.Compression.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
Microsoft.EntityFrameworkCore.Query: Error: An exception occurred while iterating over the results of a query for context type 'WaiterEval.Services.MyDbContext'.
MySqlConnector.MySqlException (0x80004005): Unknown column 's.ManagerGroup_id' in 'field list'
这是 Aql 查询抛出错误的错误日志。
数据库是现有的，不是通过迁移创建的。对于遇到同样问题的每个人，只需检查 EF 是否为 List 生成了联结表，但在您的数据库中名称不同。 就我而言，它是通过以下方式解决的：
[Table("ManagerGroups")]
public class ManagerGroup
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int ManagerGroup_id { get; set; }
// This creates a junction table with Staff
public List<Staff> AssignedStaff { get; set;} = new List<Staff>();
}
}
[Table("Staff")]
public class Staff : User
{
[DatabaseGenerated(DatabaseGeneratedOption.None)]
[ForeignKey("User")]
public int staff_id
{
get => User_id;
set => User_id = value;
}
//Option 1 to fix:
public List<ManagerGroup> managergroups { get; set;} = new List<ManagerGroup>();
}
将其添加到 MyDbContext 类
//Option 1:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<ManagerGroup>()
.HasMany(mg => mg.AssignedStaff)
.WithMany(s => s.ManagerGroups)
.UsingEntity(j => j.ToTable("ManagerGroups_AssignedStaff"));
}
//Option 2: (add a new class to represent the junction table)
public DbSet<ManagerGroup_AssignedStaff> ManagerGroups_AssignedStaff { get; set; }
modelBuilder.Entity<ManagerGroupAssignedStaff>()
.HasKey(e => new { e.ManagerGroup_id, e.Staff_id });
对于选项 2，您还需要一个新课程
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace WaiterEval.Models
{
[Table("ManagerGroups_AssignedStaff")]
public class ManagerGroupAssignedStaff
{
[Key]
[Column(Order = 1)]
public int ManagerGroup_id { get; set; }
[Key]
[Column(Order = 2)]
public int Staff_id { get; set; }
}
}