/// <summary>
/// 克隆
/// </summary>
/// <returns>SQL元素集合</returns>
public virtual object Clone()
{
SqlElementCollection collection = new SqlElementCollection();
foreach (SqlElement item in this)
{
collection.Add(item.Clone() as SqlElement);
}
return(collection);
}
/// <summary>
/// 创建子对象集合。
/// </summary>
protected void CreateChildCollection()
{
this.childCollection = new SqlElementCollection();
}