The primary purpose of the systems _________ stage of the SDLC is to gather information about the existing system to determine the requirements for an enhanced system or a new system.
A. analysis
B. design
C. investigation
D. operation
E. testing
查看答案
In a relational database, the primary key of one table is donated to another table as:
A. The title key
B. The entity key
C. The column key
D. The relational key
E. The foreign key
【单选题】 ______操作符在两个操作数中有一个（不是全部）为 True 时返回 True
PHP不允许的注释符号是（）
A. //
B.
C.
D. /*...*/
下列不正确的变量名是（）
A. $_test
B. $2abc
C. $Var
D. $x_2
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