The meanings of the attribute characters are shown below 属性字符的含义如下所示：
2.
You must specify all attributes that you want the section to have ; an omitted attribute character causes that attribute bit to be turned off 以下列出的属性字符不区分大小写。必须指定您希望节具有的所有属性；省略的属性字符将导致该属性位被关闭。
3.
2 ) semantic description methods based on metadata we construct a semantic model of metadata to describe attributes characters . the model includes data schema and data content statistic 2 )基于元数据的语义描述方法以数据库元数据为基础，建立数学模型，用于描述数据库对象的语义特征，涉及范围包括数据模式和数据内容统计。
