实体框架 - 从实体获取表名称

Question

我正在使用Entity Framework 4.1和Code First方法.我能够获取我的实体的存储模型类型和列名:

var items = context.ObjectContext.MetadataWorkspace.GetItems<EntityType>(DataSpace.SSpace);

foreach (var i in items)
{
    Console.WriteLine("Table Name: {0}", i.Name);

    Console.WriteLine("Keys:");
    foreach (var key in i.KeyMembers)
        Console.WriteLine("\t{0} ({1})", key.Name, key.TypeUsage.EdmType.FullName);

    Console.WriteLine("Members:");
    foreach (var member in i.Members)
        Console.WriteLine("\t{0} ({1})", member.Name, member.TypeUsage.EdmType.FullName);
}

我需要的是获取实体映射到的真实表名.有不同的方法来指定(通过使用Fluent-API .ToTable(),DataAnnotation [TableAttribute]).

有没有通用的方法来获得这些信息？

Answer 1

我发现获取表名的最简单方法如下:

var tables = Context.MetadataWorkspace.GetItems(System.Data.Metadata.Edm.DataSpace.CSpace)
                .Where(x => (x.MetadataProperties.Contains("NamespaceName") ? String.Compare(x.MetadataProperties["NamespaceName"].Value.ToString(), "Model", true) == 0 : false)
                && !x.MetadataProperties.Contains("IsForeignKey")
                && x.MetadataProperties.Contains("KeyMembers"));

这将获得表实体.

然后,您可以执行以下操作以提取名称:

            foreach (var item in tables)
            {
                EntityType itemType = (EntityType)item;
                String TableName = itemType.Name;
            }

请注意,如果您复制上下文,则需要撤消该上下文.

Answer 2

EF 6.1,代码优先:

public static string GetTableName<T>(this DbContext context) where T : class
{
    ObjectContext objectContext = ((IObjectContextAdapter)context).ObjectContext;
    return objectContext.GetTableName(typeof(T));
}

public static string GetTableName(this DbContext context, Type t)
{
    ObjectContext objectContext = ((IObjectContextAdapter)context).ObjectContext;
    return objectContext.GetTableName(t);
}

private static readonly Dictionary<Type,string> TableNames = new Dictionary<Type, string>();

public static string GetTableName(this ObjectContext context, Type t)
{
    string result;

    if (!TableNames.TryGetValue(t, out result))
    {
        lock (TableNames)
        {
            if (!TableNames.TryGetValue(t, out result))
            {

                string entityName = t.Name;

                ReadOnlyCollection<EntityContainerMapping> storageMetadata = context.MetadataWorkspace.GetItems<EntityContainerMapping>(DataSpace.CSSpace);

                foreach (EntityContainerMapping ecm in storageMetadata)
                {
                    EntitySet entitySet;
                    if (ecm.StoreEntityContainer.TryGetEntitySetByName(entityName, true, out entitySet))
                    {
                        result = entitySet.Schema + "." + entitySet.Table;//TODO: brackets
                        break;
                    }
                }

                TableNames.Add(t,result);
            }
        }
    }

    return result;
}