Существует уже объект с именем «Сотрудник» в базе данных

Question

я пытаюсь обновить свою базу данных, но у меня есть эта ошибка:

There is already an object named 'Employee' in the database.

Это моя последняя миграция файла:

public partial class explain : DbMigration 
    { 
     public override void Up() 
     { 
      DropForeignKey("dbo.Employee", "Person_PersonId", "dbo.Person"); 
      DropForeignKey("dbo.Receptionist", "PersonId", "dbo.Employee"); 
      DropIndex("dbo.Employee", new[] { "Person_PersonId" }); 
      CreateTable(
       "dbo.Employee", 
       c => new 
        { 
         PersonId = c.Int(nullable: false), 
         Receptionist_PersonId = c.Int(), 
         Salary = c.Int(nullable: false), 
         Hiredate = c.DateTime(nullable: false), 
         isManager = c.Boolean(nullable: false), 
        }) 
       .PrimaryKey(t => t.PersonId) 
       .ForeignKey("dbo.Person", t => t.PersonId) 
       .ForeignKey("dbo.Receptionist", t => t.Receptionist_PersonId) 
       .Index(t => t.PersonId) 
       .Index(t => t.Receptionist_PersonId); 

      AddForeignKey("dbo.Receptionist", "PersonId", "dbo.Employee", "PersonId"); 
      DropTable("dbo.Employee"); 
     } 

     public override void Down() 
     { 
      CreateTable(
       "dbo.Employee", 
       c => new 
        { 
         PersonId = c.Int(nullable: false), 
         Salary = c.Int(nullable: false), 
         Hiredate = c.DateTime(nullable: false), 
         isManager = c.Boolean(nullable: false), 
         Person_PersonId = c.Int(nullable: false), 
        }) 
       .PrimaryKey(t => t.PersonId); 

      DropForeignKey("dbo.Employee", "Receptionist_PersonId", "dbo.Receptionist"); 
      DropForeignKey("dbo.Receptionist", "PersonId", "dbo.Employee"); 
      DropForeignKey("dbo.Employee", "PersonId", "dbo.Person"); 
      DropIndex("dbo.Employee", new[] { "Receptionist_PersonId" }); 
      DropIndex("dbo.Employee", new[] { "PersonId" }); 
      DropTable("dbo.Employee"); 
      CreateIndex("dbo.Employee", "Person_PersonId"); 
      AddForeignKey("dbo.Receptionist", "PersonId", "dbo.Employee", "PersonId"); 
      AddForeignKey("dbo.Employee", "Person_PersonId", "dbo.Person", "PersonId"); 
     } 
    } 

Сотрудник .cs модель

public class Employee : Person 
    { 
     public Employee() 
     { 
      EmployeeSchedule = new HashSet<EmployeeSchedule>(); 
      Vacation = new HashSet<Vacation>(); 
     } 

     [Required] 
     [Display(Name = "Wynagrodzenie")] 
     public int Salary { get; set; } 

     [Required] 
     [Display(Name = "Data zatrudnienia")] 
     public DateTime Hiredate { get; set; } 

     [Display(Name = "Kierownik")] 
     public bool isManager { get; set; } 

     public virtual ICollection<EmployeeSchedule> EmployeeSchedule { get; set; } 

     public virtual Lifeguard Lifeguard { get; set; } 

     public virtual Receptionist Receptionist { get; set; } 

     public virtual Trainer Trainer { get; set; } 
     public virtual ICollection<Vacation> Vacation { get; set; } 
    } 

Person.cs

public abstract class Person 
    { 
     [Key] 
     [DatabaseGenerated(DatabaseGeneratedOption.Identity)] 
     public int PersonId { get; set; } 

     [Required] 
     public long Pesel { get; set; } 

     [Required] 
     [StringLength(30, ErrorMessage = "Imię nie może zawierać więcej niż 30 znaków.")] 
     [Display(Name = "Imię")] 
     public string FirstName { get; set; } 

     [Required] 
     [StringLength(60, ErrorMessage = "Nazwisko nie może zawierać wiecej niż 60 znaków.")] 
     [Display(Name = "Nazwisko")] 
     public string LastName { get; set; } 

     [Required] 
     [EmailAddress(ErrorMessage = "Błędny format adresu e-mail.")] 
     public string Email { get; set; } 

     [Required] 
     [DataType(DataType.Date)] 
     [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)] 
     [Display(Name = "Data urodzenia")] 
     public DateTime DateOfBirth { get; set; } 
     [NotMapped] 
     public int age; 
     [NotMapped] 
     public int Age 
     { 
      get 
      { 
       DateTime today = DateTime.Today; 
       age = today.Year - DateOfBirth.Year; 
       if (DateOfBirth > today.AddYears(-age)) 
       { 
        age--; 
       } 
       return age; 
      } 
     } 

     [NotMapped] 
     [Display(Name="Imię i Nazwisko")] 
     public string FullName 
     { 
      get 
      { 
       return FirstName + " " + LastName; 
      } 
     } 

    } 

Трассировка стека:

[SqlException (0x80131904): There is already an object named 'Employee' in the database.]
System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action 1 wrapCloseInAction) +2418102
System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action 1 wrapCloseInAction) +5694456 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) +285
System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady) +3731
System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async, Int32 timeout, Boolean asyncWrite) +959
System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource 1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite) +272
System.Data.SqlClient.SqlCommand.ExecuteNonQuery() +280
System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<NonQuery>b__0(DbCommand t, DbCommandInterceptionContext 1 c) +36
System.Data.Entity.Infrastructure.Interception.InternalDispatcher 1.Dispatch(TTarget target, Func 3 operation, TInterceptionContext interceptionContext, Action 3 executing, Action 3 executed) +138
System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.NonQuery(DbCommand command, DbCommandInterceptionContext interceptionContext) +476
System.Data.Entity.Internal.InterceptableDbCommand.ExecuteNonQuery() +177 System.Data.Entity.Migrations.DbMigrator.ExecuteSql(MigrationStatement migrationStatement, DbConnection connection, DbTransaction transaction, DbInterceptionContext interceptionContext) +194
System.Data.Entity.Migrations.Infrastructure.MigratorBase.ExecuteSql(MigrationStatement migrationStatement, DbConnection connection, DbTransaction transaction, DbInterceptionContext interceptionContext) +62
System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable 1 migrationStatements, DbConnection connection, DbTransaction transaction, DbInterceptionContext interceptionContext) +113
System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsWithinTransaction(IEnumerable 1 migrationStatements, DbTransaction transaction, DbInterceptionContext interceptionContext) +110
System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsWithinNewTransaction(IEnumerable 1 migrationStatements, DbConnection connection, DbInterceptionContext interceptionContext) +172
System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable 1 migrationStatements, DbConnection connection, DbInterceptionContext interceptionContext) +429
System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable 1 migrationStatements, DbConnection connection) +646
System.Data.Entity.Migrations.<>c__DisplayClass30.<ExecuteStatements>b__2e() +66 System.Data.Entity.SqlServer.<>c__DisplayClass1.<Execute>b__0() +34 System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Func 1 operation) +251
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action operation) +196
System.Data.Entity.Migrations.DbMigrator.ExecuteStatements(IEnumerable 1 migrationStatements, DbTransaction existingTransaction) +327
System.Data.Entity.Migrations.DbMigrator.ExecuteStatements(IEnumerable 1 migrationStatements) +39
System.Data.Entity.Migrations.Infrastructure.MigratorBase.ExecuteStatements(IEnumerable 1 migrationStatements) +42
System.Data.Entity.Migrations.DbMigrator.ExecuteOperations(String migrationId, VersionedModel targetModel, IEnumerable 1 operations, IEnumerable 1 systemOperations, Boolean downgrading, Boolean auto) +1372 System.Data.Entity.Migrations.DbMigrator.ApplyMigration(DbMigration migration, DbMigration lastMigration) +783
System.Data.Entity.Migrations.Infrastructure.MigratorBase.ApplyMigration(DbMigration migration, DbMigration lastMigration) +56
System.Data.Entity.Migrations.DbMigrator.Upgrade(IEnumerable 1 pendingMigrations, String targetMigrationId, String lastMigrationId) +192 System.Data.Entity.Migrations.Infrastructure.MigratorBase.Upgrade(IEnumerable 1 pendingMigrations, String targetMigrationId, String lastMigrationId) +59 System.Data.Entity.Migrations.DbMigrator.UpdateInternal(String targetMigration) +888
System.Data.Entity.Migrations.<>c__DisplayClassc.<Update>b__b() +38
System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) +516
System.Data.Entity.Migrations.Infrastructure.MigratorBase.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) +42
System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration) +136
System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update() +33 System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func 3 createMigrator, ObjectContext objectContext) +175 System.Data.Entity.Internal.InternalContext.CreateDatabase(ObjectContext objectContext, DatabaseExistenceState existenceState) +150
System.Data.Entity.Database.Create(DatabaseExistenceState existenceState) +444
System.Data.Entity.DropCreateDatabaseAlways 1.InitializeDatabase(TContext context) +158
System.Data.Entity.Internal.<>c__DisplayClassf 1.b__e() +165 System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) +110
System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() +660 System.Data.Entity.Internal.LazyInternalContext.b__4(InternalContext c) +31
System.Data.Entity.Internal.RetryAction 1.PerformAction(TInput input) +143 System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action 1 action) +292
System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase() +123 System.Data.Entity.Internal.InternalContext.Initialize() +42 System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) +39
System.Data.Entity.Internal.Linq.InternalSet 1.Initialize() +137
System.Data.Entity.Internal.Linq.InternalSet 1.get_InternalContext() +38 System.Data.Entity.Internal.Linq.InternalSet 1.FindAsync(CancellationToken cancellationToken, Object[] keyValues) +58
System.Data.Entity.DbSet 1.FindAsync(CancellationToken cancellationToken, Object[] keyValues) +70
System.Data.Entity.DbSet 1.FindAsync(Object[] keyValues) +69
Microsoft.AspNet.Identity.EntityFramework.EntityStore 1.GetByIdAsync(Object id) +104
Microsoft.AspNet.Identity.EntityFramework.d__6c.MoveNext() +275 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter 1.GetResult() +28 Microsoft.AspNet.Identity.CultureAwaiter 1.GetResult() +123 Microsoft.AspNet.Identity.Owin.<b__1>d__4.MoveNext() +1519 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Security.Cookies.d__2.MoveNext() +3729 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +28 Microsoft.Owin.Security.Infrastructure.d__0.MoveNext() +810 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Security.Infrastructure.d__0.MoveNext() +427 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.AspNet.Identity.Owin.d__0.MoveNext() +641 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.AspNet.Identity.Owin.d__0.MoveNext() +641 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.AspNet.Identity.Owin.d__0.MoveNext() +641 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.AspNet.Identity.Owin.d__0.MoveNext() +641 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.d__5.MoveNext() +287 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter.GetResult() +26 Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.d__2.MoveNext() +272 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +26 Microsoft.Owin.Host.SystemWeb.Infrastructure.ErrorState.Rethrow() +33 Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) +150
Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) +42
System.Web.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +380 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

Попробуйте переместить DropTable заявление перед утверждением Создание в миграции. Таким образом вы удаляете существующую таблицу Employee перед созданием нового.