数据库表结构

SELECT A.column_name 字段名, A.data_type 数据类型, A.data_length 长度,
       A.data_precision 整数位, A.Data_Scale 小数位, A.nullable 允许空值,
       B.comments 备注, A.Column_Id 序号
  FROM user_tab_columns A, user_col_comments B
 WHERE A.Table_Name = B.Table_Name
   AND A.Column_Name = B.Column_Name
   AND A.Table_Name = 'B_CITY'
 ORDER BY A.Column_Id