【单选题】The slope of the line with equation y=ax+b is greater than the slope of the line with equation y=cx+b.Which of the following statements mustbe true about the relationship between a and c?
【判断题】We can use query languages to express the relational databases. The "query" language is not only including the function of retrieving information from database, but also the insertion, deletion, and u...
【单选题】What does the term “atomic” mean in the context of relational databases?
A.
One unit of information that cannot be decomposed.
B.
A column or row of data. Depends on the context.
C.
A tuple that cannot be reduced.
D.
Fixed schema of a particular database.
【单选题】直流电机的换向器安装在 上, 电刷安装在 上。
【单选题】The reason that many people find it hard to relax these days is that________.
A.
they are suffering from the effects of excessive stress
B.
they are working harder than they used to
C.
they are often too busy to find time
D.
they have no idea what relaxation means to them
【简答题】直流电动机的结构主要由____和____两个基本部分组成,其电刷装置是安装在定子,而换向器是安装在电钮(转子) 上。
【单选题】Which of the following technologies is better equipped than relational databases to handle big data?
【单选题】The slope of the consumption function is
A.
less than the slope of the 45-degree line but not equal to zero.
B.
greater than the slope of the 45-degree line.
C.
equal to the slope of the 45-degree line.
【单选题】According to Codd's _____ rule of relational databases, if the system supports low-level access to the data, users must not be allowed to bypass the integrity rules of the database.
【单选题】Find the slope of the line through P (–9,1) and Q (–3,–11).