Sqlite.net 扩展，无法使用 GetWithChildren 获取数据

Question

我正在创建一个数据库，其中多个类作为其他类的子类。使用外键编写工作正常，但是当我尝试取回数据时，它会引发错误:

An unhandled exception of type 'SQLiteNetExtensions.Exceptions.IncorrectRelationshipException' occurred in SQLiteNetExtensions.dll

Additional information: MatchDetail.timeline: At least one entity in a OneToOne relationship must have Foreign Key

这是我的创建代码:

SQLiteConnection db = new SQLiteConnection(new SQLite.Net.Platform.Win32.SQLitePlatformWin32(), "Matches.db3");
db.CreateTable<ParticipantIdentity>();
db.CreateTable<MatchDetail>();
db.CreateTable<Timeline>();
db.InsertWithChildren(md, true);
var m = db.GetWithChildren<MatchDetail>(matchId, true);

我的类(class):

[Table("Matches")]
public class MatchDetail
{
    [PrimaryKey]
    public long matchId { get; set; }
    public int mapId { get; set; }
    [JsonConverter(typeof(DateTimeConverterFromLong))]
    public DateTime MatchCreation { get; set; }
    public long matchDuration { get; set; }
    public MatchMode matchMode { get; set; }
    public MatchType matchType { get; set; }
    public string matchVersion { get; set; }

    public string platformId { get; set; }
    public Queuetype queueType { get; set; }
    public Region region { get; set; }
    public Season season { get; set; }

    [ForeignKey(typeof(Timeline), Name = "TimelineId"), Indexed]
    public int timelineId { get; set; }
    [OneToOne("TimelineId", CascadeOperations = CascadeOperation.All)]
    public Timeline timeline { get; set; }

    [ForeignKey(typeof(ParticipantIdentity), Name = "ParticipantId"), Indexed]
    public int participantIdentitiesId { get; set; }
    [ManyToOne("ParticipantId", CascadeOperations = CascadeOperation.All)]
    public List<ParticipantIdentity> participantIdentities { get; set; }
}

其他类只是一个 id 和一些其他基本类型，我一直在努力解决这个问题，但它就是不想工作。

编辑:

[ForeignKey(typeof(ParticipantIdentity))]
public int participantIdentitiesId { get; set; }
[OneToMany(CascadeOperations = CascadeOperation.All)]
public List<ParticipantIdentity> participantIdentities { get; set; }

有错误:

An unhandled exception of type 'SQLiteNetExtensions.Exceptions.IncorrectRelationshipException' occurred in SQLiteNetExtensions.dll

Additional information: MatchDetail.participantIdentities: Unable to find foreign key for OneToMany relationship

Answer 1

您手动指定外键名为“TimelineId”，但实际上外键名为“timelineId”(注意首字母大写)。

改变这个:

[ForeignKey(typeof(Timeline), Name = "TimelineId"), Indexed]
public int timelineId { get; set; }
[OneToOne("TimelineId", CascadeOperations = CascadeOperation.All)]
public Timeline timeline { get; set; }

对此:

[ForeignKey(typeof(Timeline)]
public int timelineId { get; set; }
[OneToOne(CascadeOperations = CascadeOperation.All)]
public Timeline timeline { get; set; }

显式声明外键名称可能会导致重构问题，因此除非严格要求，否则这是推荐的方式。

另一个关系被声明为 ManyToOne但它实际上是 OneToMany .要使其工作，您必须更改属性类型并将外键移动到另一端。

改变关系:

[ForeignKey(typeof(ParticipantIdentity), Name = "ParticipantId"), Indexed]
public int participantIdentitiesId { get; set; }
[ManyToOne("ParticipantId", CascadeOperations = CascadeOperation.All)]
public List<ParticipantIdentity> participantIdentities { get; set; }

有了这个:

[OneToMany(CascadeOperations = CascadeOperation.All)]
public List<ParticipantIdentity> participantIdentities { get; set; }

并将外键添加到 MatchDetail到 ParticipantIdentity类(class):

[ForeignKey(typeof(MatchDetail)]
public int matchDetailId { get; set; }

查看 SQLite-Net 扩展 documentation和 sample project更多示例。