我正在尝试设置EntityFramework Plus' Audit Auto-Save feature，但似乎我陷入了一个非常愚蠢的问题。我正在遵循“通过覆盖SaveChanges和SaveChangesAsync自动保存”路径，但是我尝试使用代码优先，因为我要使用的项目已经运行了一段时间了。话虽如此，我的DbContext看起来像这样：
public class CadastralDbContext : DbContext
{
public CadastralDbContext(DbContextOptions<CadastralDbContext> options) : base(options) { }
static CadastralDbContext()
{
AuditManager.DefaultConfiguration.AutoSavePreaction = (context,audit) =>
(context as CadastralDbContext).AuditEntries.AddRange(audit.Entries);
}
public DbSet<AuditEntry> AuditEntries { get; set; }
public DbSet<AuditEntryProperty> AuditEntryProperties { get; set; }
//Ommited my DbSets
protected override void OnmodelCreating(ModelBuilder modelBuilder)
{
modelBuilder.ApplyConfigurationsFromAssembly(typeof(CadastralDbContext).Assembly);
/*** Ignore these for now ***/
//modelBuilder.Entity<AuditEntry>().Ignore(x => x.Properties);
//modelBuilder.Entity<AuditEntryProperty>().Ignore(x => x.Parent);
}
public override int SaveChanges()
{
var audit = new Audit();
audit.PreSaveChanges(this);
var rowAffecteds = base.SaveChanges();
audit.PostSaveChanges();
if (audit.Configuration.AutoSavePreaction != null)
{
audit.Configuration.AutoSavePreaction(this,audit);
base.SaveChanges();
}
return rowAffecteds;
}
public async Task<int> SaveChangesAsync()
{
return await SaveChangesAsync(CancellationToken.None);
}
public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken)
{
var audit = new Audit();
audit.PreSaveChanges(this);
var rowAffecteds = await base.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
audit.PostSaveChanges();
if (audit.Configuration.AutoSavePreaction != null)
{
audit.Configuration.AutoSavePreaction(this,audit);
await base.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
}
return rowAffecteds;
}
}
}
基本上，本教程所说的内容添加了DbSet<AuditEntry>和DbSet<AuditEntryProperty>，它们是框架本身的类。检查这些的元数据，我们有：
//
// Summary:
// An audit entry.
public class AuditEntry
{
//
// Summary:
// Gets or sets the object state entry.
[NotMapped]
public object Entity;
//
// Summary:
// Gets or sets the object state entry.
[NotMapped]
public EntityEntry Entry;
//
// Summary:
// Gets or sets the parent.
public Audit Parent;
public AuditEntry();
//
// Summary:
// Gets or sets the identifier of the audit entry.
[Column(Order = 0)]
public int AuditEntryID { get; set; }
//
// Summary:
// Gets or sets who created this object.
[Column(Order = 5)]
[MaxLength(255)]
public string CreatedBy { get; set; }
//
// Summary:
// Gets or sets the the date of the changes.
[Column(Order = 6)]
public DateTime CreatedDate { get; set; }
//
// Summary:
// Gets or sets the name of the entity set.
[Column(Order = 1)]
[MaxLength(255)]
public string entitysetName { get; set; }
//
// Summary:
// Gets or sets the name of the entity type.
[Column(Order = 2)]
[MaxLength(255)]
public string EntityTypeName { get; set; }
//
// Summary:
// Gets or sets the properties.
public List<AuditEntryProperty> Properties { get; set; }
//
// Summary:
// Gets or sets the entry state.
[Column(Order = 3)]
public AuditEntryState State { get; set; }
//
// Summary:
// Gets or sets the name of the entry state.
[Column(Order = 4)]
[MaxLength(255)]
public string StateName { get; set; }
}
和
//
// Summary:
// An audit entry property.
public class AuditEntryProperty
{
//
// Summary:
// Gets or sets the new value audited.
[NotMapped]
public PropertyEntry PropertyEntry;
public object NewValue;
public object OldValue;
public AuditEntryProperty();
//
// Summary:
// Gets or sets the name of the property internally.
[NotMapped]
public string InternalPropertyName { get; set; }
//
// Summary:
// Gets or sets a value indicating whether OldValue and NewValue is set.
[NotMapped]
public bool IsValueSet { get; set; }
//
// Summary:
// Gets or sets the name of the relation audited.
[Column(Order = 2)]
[MaxLength(255)]
public string RelationName { get; set; }
//
// Summary:
// Gets or sets the name of the property audited.
[Column(Order = 3)]
[MaxLength(255)]
public string PropertyName { get; set; }
//
// Summary:
// Gets or sets the parent.
public AuditEntry Parent { get; set; }
//
// Summary:
// Gets or sets the identifier of the audit entry property.
[Column(Order = 0)]
public int AuditEntryPropertyID { get; set; }
//
// Summary:
// Gets or sets the new value audited formatted.
[Column("NewValue",Order = 5)]
public string NewValueFormatted { get; set; }
//
// Summary:
// Gets or sets the identifier of the audit entry.
[Column(Order = 1)]
public int AuditEntryID { get; set; }
//
// Summary:
// Gets or sets the old value audited formatted.
[Column("OldValue",Order = 4)]
public string OldValueFormatted { get; set; }
}
除了两个属性：public List<AuditEntryProperty> Properties { get; set; }和public AuditEntry Parent { get; set; }之外，它看起来已经足够好了。由于未将其标记为virtual，因此添加迁移将失败。我尝试了一种变通方法，只是看是否可以获取它来生成表，而我确实成功了（前面提到的那些行）：
protected override void OnmodelCreating(ModelBuilder modelBuilder)
{
//...
modelBuilder.Entity<AuditEntry>().Ignore(x => x.Properties);
modelBuilder.Entity<AuditEntryProperty>().Ignore(x => x.Parent);
}
这似乎禁用了两个表都具有的PrimaryKey-ForeignKey关系，这些关系是在框架本身内部设置的，因为没有迹象表明我应该手动进行操作。我什至试图运行该脚本只是为了看看会发生什么，结果是灾难性的：
CREATE INDEX [IX_AuditEntryID] ON [dbo].[AuditEntryProperties]([AuditEntryID])
GO
ALTER TABLE [dbo].[AuditEntryProperties]
ADD CONSTRAINT [FK_dbo.AuditEntryProperties_dbo.AuditEntries_AuditEntryID]
FOREIGN KEY ([AuditEntryID])
REFERENCES [dbo].[AuditEntries] ([AuditEntryID])
ON DELETE CASCADE
GO
这使我在插入时遇到以下SQL错误：String or binary data would be truncated。因此，我只是回滚到以前的状态，在该状态下框架具有“ 50％的输出”，因为每当用户请求插入，更新或删除操作时，它都会将记录保存到AuditEntry表（其中包含表等数据）没有任何东西会保留在AuditEntryProperties中（新值，旧值，列），除了这些属性被忽略是所有这些的原因之外，我无法想到其他任何东西。
我以为我可以覆盖AuditEntry和AuditEntryProperties，但这听起来像是一个很大的愚蠢的解决方法。我不是数据库专家，我在这里想念什么？
编辑：忘记添加迁移代码：
migrationBuilder.Createtable(
name: "AuditEntries",columns: table => new
{
AuditEntryID = table.Column<int>(nullable: false)
.Annotation("SqlServer:Identity","1,1"),CreatedBy = table.Column<string>(maxLength: 255,nullable: true),CreatedDate = table.Column<DateTime>(nullable: false),entitysetName = table.Column<string>(maxLength: 255,EntityTypeName = table.Column<string>(maxLength: 255,State = table.Column<int>(nullable: false),StateName = table.Column<string>(maxLength: 255,nullable: true)
},constraints: table =>
{
table.PrimaryKey("PK_AuditEntries",x => x.AuditEntryID);
});
migrationBuilder.Createtable(
name: "AuditEntryProperties",columns: table => new
{
AuditEntryPropertyID = table.Column<int>(nullable: false)
.Annotation("SqlServer:Identity",AuditEntryID = table.Column<int>(nullable: false),PropertyName = table.Column<string>(maxLength: 255,RelationName = table.Column<string>(maxLength: 255,NewValue = table.Column<string>(nullable: true),OldValue = table.Column<string>(nullable: true)
},constraints: table =>
{
table.PrimaryKey("PK_AuditEntryProperties",x => x.AuditEntryPropertyID);
});
编辑2 试图通过Fluent API添加FK：
protected override void OnmodelCreating(ModelBuilder modelBuilder)
{
modelBuilder.ApplyConfigurationsFromAssembly(typeof(CadastralDbContext).Assembly);
modelBuilder.Entity<AuditEntryProperty>().HasOne<AuditEntry>(prop => prop.Parent).WithMany(a => a.Properties).HasForeignKey(prop => prop.AuditEntryID);
}
由于这些属性不是虚拟的，因此仍然无法执行迁移。