[收藏本方案]

今天考数据库,这是题目和我的答案![1]

[入库：2005年8月18日] [更新：2007年3月24日]

本文简介：选择自 soaktech 的 blog
首页 下页 尾页 [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32]

题目:

一.单项选择

 

1.

 

with respect to a relational table, what is a key?

 

 

 

 (a) a minimal subset of columns that uniquely identifies a row in the table
 (b) the id and password needed to access the table
 (c) the subset of all the rows and columns in the table that are visible to all users in the database system
 (d) the one column that uniquely identifies a row in the table

 

 

 

2.

 

which of the following is true about the number of primary keys and alternate keys with respect to a table?

 

 

 

 (a) there can be many primary keys, but only one alternate key.
 (b) there can be only one primary key, but many alternate keys.
 (c) there can be only one primary key and only one alternate key.
 (d) there can be many primary keys and many alternate keys.

首页 下页 尾页 [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32]
本文关键：今天考数据库,这是题目和我的答案!
　　相关方案
Google
 

本站最佳浏览方式为 分辨率 1024x768 IE 6.0（或更高版本的 IE浏览器）

go top