EF Core Add-Migration 错误属性已存在

Posted 2023-03-29

【中文标题】EF Core Add-Migration 错误属性已存在

【英文标题】：EF Core Add-Migration error property already exists

【发布时间】：2021-12-28 10:50:53

【问题描述】：

我正在尝试创建另一个迁移，但我不明白为什么会一直出现此错误。为什么它甚至尝试再次添加该属性？我在之前的迁移中添加了它，现在数据库是最新的，我想添加其他更改。我做错了什么？

PM> Add-Migration Northwind1.3
Build started...
Build succeeded.
System.InvalidOperationException: The property or navigation 'EmployeeRole' cannot be added to the entity type 'AdoNet.Entities.EF.Employee' because a property or navigation with the same name already exists on entity type 'AdoNet.Entities.EF.Employee'.
   at Microsoft.EntityFrameworkCore.Metadata.Internal.EntityType.AddNavigation(MemberIdentity navigationMember, ForeignKey foreignKey, Boolean pointsToPrincipal)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.EntityType.AddNavigation(String name, ForeignKey foreignKey, Boolean pointsToPrincipal)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.ForeignKey.Navigation(Nullable`1 propertyIdentity, ConfigurationSource configurationSource, Boolean pointsToPrincipal)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.ForeignKey.SetDependentToPrincipal(String name, ConfigurationSource configurationSource)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.InternalForeignKeyBuilder.HasNavigations(Nullable`1 navigationToPrincipal, Nullable`1 navigationToDependent, EntityType principalEntityType, EntityType dependentEntityType, ConfigurationSource configurationSource)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.InternalForeignKeyBuilder.HasNavigations(Nullable`1 navigationToPrincipal, Nullable`1 navigationToDependent, ConfigurationSource configurationSource)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.InternalForeignKeyBuilder.HasNavigation(String name, Boolean pointsToPrincipal, ConfigurationSource configurationSource)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.InternalEntityTypeBuilder.HasRelationship(EntityType targetEntityType, Nullable`1 navigationToTarget, Nullable`1 inverseNavigation, Nullable`1 setTargetAsPrincipal, ConfigurationSource configurationSource, Nullable`1 required)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.InternalEntityTypeBuilder.HasRelationship(EntityType targetEntityType, String navigationName, ConfigurationSource configurationSource, Nullable`1 targetIsPrincipal)
   at Microsoft.EntityFrameworkCore.Metadata.Builders.EntityTypeBuilder.HasOneBuilder(MemberIdentity navigationId, EntityType relatedEntityType)
   at Microsoft.EntityFrameworkCore.Metadata.Builders.EntityTypeBuilder.HasOne(String relatedTypeName, String navigationName)
   at AdoNet.Migrations.NorthwindContextModelSnapshot.<>c.<BuildModel>b__0_31(EntityTypeBuilder b) in D:\Programming\Csharp\epam-inner\homework\adonet\AdoNet\Migrations\NorthwindContextModelSnapshot.cs:line 1086
   at Microsoft.EntityFrameworkCore.ModelBuilder.Entity(String name, Action`1 buildAction)
   at AdoNet.Migrations.NorthwindContextModelSnapshot.BuildModel(ModelBuilder modelBuilder) in D:\Programming\Csharp\epam-inner\homework\adonet\AdoNet\Migrations\NorthwindContextModelSnapshot.cs:line 1084
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSnapshot.CreateModel()
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSnapshot.get_Model()
   at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.ScaffoldMigration(String migrationName, String rootNamespace, String subNamespace, String language)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType, String namespace)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType, String namespace)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
The property or navigation 'EmployeeRole' cannot be added to the entity type 'AdoNet.Entities.EF.Employee' because a property or navigation with the same name already exists on entity type 'AdoNet.Entities.EF.Employee'.

员工：

public partial class Employee

    public Employee()
    
        EmployeeTerritories = new HashSet<EmployeeTerritory>();
        InverseReportsToNavigation = new HashSet<Employee>();
        Orders = new HashSet<Order>();
    

    public int EmployeeId  get; set; 
    public string LastName  get; set; 
    public string FirstName  get; set; 
    public string Title  get; set; 
    public string TitleOfCourtesy  get; set; 
    public DateTime? BirthDate  get; set; 
    public DateTime? HireDate  get; set; 
    public string Address  get; set; 
    public string City  get; set; 
    public string Region  get; set; 
    public string PostalCode  get; set; 
    public string Country  get; set; 
    public string HomePhone  get; set; 
    public string Extension  get; set; 
    public byte[] Photo  get; set; 
    public string Notes  get; set; 
    public int? ReportsTo  get; set; 
    public string PhotoPath  get; set; 
    public int? EmployeeRoleId  get; set; 

    public virtual EmployeeRole EmployeeRole  get; set; 
    public virtual Employee ReportsToNavigation  get; set; 
    public virtual ICollection<EmployeeTerritory> EmployeeTerritories  get; set; 
    public virtual ICollection<Employee> InverseReportsToNavigation  get; set; 
    public virtual ICollection<Order> Orders  get; set; 

员工角色：

public partial class EmployeeRole

    public EmployeeRole()
    
        Employees = new HashSet<Employee>();
    

    public int EmployeeRoleId  get; set; 
    public string EmployeeRoleName  get; set; 

    public virtual ICollection<Employee> Employees  get; set; 

来自NorthwindContext中Employee的modelBuilder：

entity.HasOne(d => d.EmployeeRole)
    .WithMany(p => p.Employees)
    .HasForeignKey(d => d.EmployeeRoleId);

由于某种原因，EmployeeRole 中的 EmployeeRoleId 属性也被淡化了。

【参考方案1】：

我认为数据库中的 _MigrationHistory 表没有更新。检查 _MigrationHistory 以了解此表中应用的最后一次迁移

【讨论】：

我之前有 2 次迁移，它们都在 __EFMigrationsHistory 表中。

先检查数据库表的关系，确认无误。然后，如果不行，将导航或属性的名称（ EmployeeRole virtual public EmployeeRole get; set; 更改为 EmployeeRole virtual public EmployeeRole _test get; set;;

数据库中的一切都是正确的

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