首先從實體框架6數據庫中的數據庫中獲取列名，並在映射中使用不同的屬性名稱

Question

我遇到的情況是我的表名與使用EF 6中的映射的模型上的類屬性不同。模型和數據庫如下所示：

 public class AGENTMap : EntityTypeConfiguration<AGENT>
{
    public AGENTMap()
    {
        // Primary Key
        this.HasKey(t => new {t.AgentCode });

        // Properties
        this.Property(t => t.AgentCode)
            .HasMaxLength(10);

        this.Property(t => t.AgentName)
            .HasMaxLength(30);


        // Table & Column Mappings
        this.ToTable("AGENT");
        this.Property(t => t.agent_cd).HasColumnName("agent_cd");
        this.Property(t => t.agent_nm).HasColumnName("agent_nm");
    }
}

這相當於具有這些屬性的AGENT類。 問題是當我嘗試使用此代碼段獲取主鍵時：

ObjectContext objectContext = ((IObjectContextAdapter)_context).ObjectContext;
        ObjectSet<TEntity> objSet = objectContext.CreateObjectSet<TEntity>();
        IEnumerable<string> keyNames = objSet.EntitySet.ElementType.KeyMembers
            .Where(p => p.MetadataProperties.Any(m => m.PropertyKind == PropertyKind.Extended
                              && Convert.ToString(m.Value) == "Identity"))
                                                    .Select(e => e.Name).ToList();

        return keyNames;

它返回Mapping類的Property Name。 我想得到“agent_cd”..這是db列名。在EF6中是否有辦法在Db上獲取確切的列名？

Answer 1

Rowan Miller 寫了另一篇博文 ，詳細介紹了如何在EF 6中獲取列名。

public static string GetColumnName(Type type, string propertyName, DbContext context)
{
    var metadata = ((IObjectContextAdapter)context).ObjectContext.MetadataWorkspace;

    // Get the part of the model that contains info about the actual CLR types
    var objectItemCollection = ((ObjectItemCollection)metadata.GetItemCollection(DataSpace.OSpace));

    // Get the entity type from the model that maps to the CLR type
    var entityType = metadata
            .GetItems<EntityType>(DataSpace.OSpace)
            .Single(e => objectItemCollection.GetClrType(e) == type);

    // Get the entity set that uses this entity type
    var entitySet = metadata
        .GetItems<EntityContainer>(DataSpace.CSpace)
        .Single()
        .EntitySets
        .Single(s => s.ElementType.Name == entityType.Name);

    // Find the mapping between conceptual and storage model for this entity set
    var mapping = metadata.GetItems<EntityContainerMapping>(DataSpace.CSSpace)
            .Single()
            .EntitySetMappings
            .Single(s => s.EntitySet == entitySet);

    // Find the storage entity set (table) that the entity is mapped
    var tableEntitySet = mapping
        .EntityTypeMappings.Single()
        .Fragments.Single()
        .StoreEntitySet;

    // Return the table name from the storage entity set
    var tableName = tableEntitySet.MetadataProperties["Table"].Value ?? tableEntitySet.Name;

    // Find the storage property (column) that the property is mapped
    var columnName = mapping
        .EntityTypeMappings.Single()
        .Fragments.Single()
        .PropertyMappings
        .OfType<ScalarPropertyMapping>()
        .Single(m => m.Property.Name == propertyName)
        .Column
        .Name;

    return tableName + "." + columnName;
}

Answer 2

可能是這篇文章可以提供幫助。 它們查詢objectContext的MetadataWorkspace屬性。 http://romiller.com/2012/04/20/what-tables-are-in-my-ef-model-and-my-database/