下面选项中关于“文件指针”概念的叙述正确的是( )。
A、文件指针就是文件位置指针,表示当前读写数据的位置
B、文件指针是程序中用FILE定义的指针变量
C、文件指针指向文件在计算机中的存储位置
D、把文件指针传给fscanf函数,就可以向文本文件中写入任意的字符
Which statement correctly describes SQL and /SQL*Plus?()
A、Both SQL and /SQL*plus allow manipulation of values in the database.
B、/SQL* Plus recognizes SQL satement and sends them to the server; SQL is the Oracle proprietary interface for executing SQL statements.
C、/SQL* Plus language for communicating with the Oracle server to access data; SQL recognizes SQL statements and sends them to the server.
D、/SQL manipulates data and table definition in the database; /SQL* Plus does not allow manipulation of values in the database.
操作系统是随着硬件和软件不断发展而逐渐形成的一套()
A、数据库系统
B、软件系统
C、程序系统
D、语言系统
The user SCOTT executes the following command successfully to increase the salary values in one of his sessions: SQL> UPDATE emp SET sal=sal*1.15 WHERE deptno=20; Before SCOTT ends the transaction, user HR who has the privileges on EMP table executes a query to fetch the salary details but finds the old salary values instead of the increased values. Why does HR still see the old data?()
A、because of redo data from redo log file
B、because of data from database buffer cache
C、because of data from a temporary tablespace
D、because of undo data from the undo tablespace
下列关于类和对象的叙述中,错误的是( )。
A、一个类只能有一个对象
B、对象是类的具体实例
C、类是对某一类对象的抽象
D、类和对象的关系是一种数据类型与变量的关系
You would like to display the system date in the format "Monday, 01 June, 2001".Which SELECT statement should you use?()
A、SELECT TO_DATE(SYSDATE, 'FMDAY, DD Month, YYYY') FROM dual;
B、SELECT TO_CHAR(SYSDATE, 'FMDD, DY Month, 'YYY') FROM dual;
C、SELECT TO_CHAR(SYSDATE, 'FMDay, DD Month, YYYY') FROM dual;
D、SELECT TO_CHAR(SYSDATE, 'FMDY, DDD Month, YYYY') FROM dual;
E、SELECT TO_DATE(SYSDATE, 'FMDY, DDD Month, YYYY') FROM dual;