我是MongoDb的新手,並使用一個簡單的類並將具有此結構的兩條記錄插入到數據庫中。當我刪除實體類屬性時,MongoDb.Driver拋出異常
public class Person
{
public int Id { get; set; }
public string Name { get; set; }
public string Property1 { get; set; }
public override string ToString()
{
return $"{{ Id: {Id}, Name: {Name} }}";
}
}
我可以通過這段代碼閱讀它們,一切都很好。
var client = new MongoClient();
var db = client.GetDatabase("test-update");
var people = db.GetCollection<Person>("people").Find(p => true).ToList();
foreach (var person in people)
{
Console.WriteLine(person.ToString());
}
結果是:
{ Id: 1, Name: person 1 }
{ Id: 2, Name: person 2 }
現在,如果我從我的Person類中刪除Property1,並再次運行讀取的代碼,我會碰到這樣的錯誤:
Unhandled Exception: System.FormatException: Element 'Property1' does not match any field or property of class Person.
at MongoDB.Bson.Serialization.BsonClassMapSerializer`1.DeserializeClass(BsonDeserializationContext context)
at MongoDB.Bson.Serialization.BsonClassMapSerializer`1.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
at MongoDB.Bson.Serialization.IBsonSerializerExtensions.Deserialize[TValue](IBsonSerializer`1 serializer, BsonDeserializationContext context)
at MongoDB.Driver.Core.Operations.CursorBatchDeserializationHelper.DeserializeBatch[TDocument](RawBsonArray batch, IBsonSerializer`1 documentSerializer, MessageEncoderSettings messageEncoderSet
tings)
at MongoDB.Driver.Core.Operations.FindCommandOperation`1.CreateCursorBatch(BsonDocument result)
at MongoDB.Driver.Core.Operations.FindCommandOperation`1.ExecuteCommand(IReadBinding binding, ServerDescription serverDescription, CancellationToken cancellationToken)
at MongoDB.Driver.Core.Operations.FindCommandOperation`1.Execute(IReadBinding binding, CancellationToken cancellationToken)
at MongoDB.Driver.Core.Operations.FindOperation`1.Execute(IReadBinding binding, CancellationToken cancellationToken)
at MongoDB.Driver.OperationExecutor.ExecuteReadOperation[TResult](IReadBinding binding, IReadOperation`1 operation, CancellationToken cancellationToken)
at MongoDB.Driver.MongoCollectionImpl`1.ExecuteReadOperation[TResult](IReadOperation`1 operation, ReadPreference readPreference, CancellationToken cancellationToken)
at MongoDB.Driver.MongoCollectionImpl`1.ExecuteReadOperation[TResult](IReadOperation`1 operation, CancellationToken cancellationToken)
at MongoDB.Driver.MongoCollectionImpl`1.FindSync[TProjection](FilterDefinition`1 filter, FindOptions`2 options, CancellationToken cancellationToken)
at MongoDB.Driver.FindFluent`2.ToCursor(CancellationToken cancellationToken)
at MongoDB.Driver.IAsyncCursorSourceExtensions.ToList[TDocument](IAsyncCursorSource`1 source, CancellationToken cancellationToken)
at ConsoleApplication.Program.Main(String[] args) in C:\Users\choro\Desktop\mongo-update\Program.cs:line 12
這只是一個測試項目,這些元數據的變化將會一直在真實項目中發生。如何管理這些更改以避免錯誤。
在EF和SQL Server中,我總是使用自動遷移,而不必考慮元數據更改。但是我不知道在MongoDb的情況下該怎麼做。
感謝
你說得對。我的觀點是必須有一種自動的方式來爲我做這件事。我不應該擔心同步課程和數據庫。 – ach