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【单选题】
电梯机房的检修梯材质为()A.
钢筋混凝土
B.
钢材
C.
木材
D.
砖砌体
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举一反三
【单选题】Which of the following is not a basic requirement of a relational database?
A.
Every column in a row must be single valued.
B.
Primary keys cannot be null.
C.
Foreign keys, if not null, must have values that correspond to the value of another foreign key in another table.
D.
All nonkey attributes in a table should describe a characteristic about the object identified by the primary key.
E.
All of the above are basic requirements of a relational database.
【单选题】SQL Server is a RDBMS( Relational Database Management System)made by Microsoft. This means that the data is stored in two dimensional(74)
A.
documents
B.
databases
C.
files
D.
tables
【简答题】根据给出的短语，写出中文意思：relational database
【单选题】SQL Server is a RDBMS(Relational Database Management System)made by Microsoft. This means that the data is stored in two dimensional(70)
A.
documents
B.
databases
C.
files
D.
tables
【简答题】Compare the advantages and disadvantages of relational database and hierarchical database
【简答题】人们根据特定的需要预先为计算机编制的指令序列称为().A. A:软件 B. B:文件 C. C:程序 D. D:集合
【简答题】记法与意义不同,但( )相同的音,称为等音。
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