From SQL*Plus, you issue this SELECT statement: https://assets.asklib.com/images/image2/2018080116203977752.jpg You use this statement to retrieve data from a data table for()。
From SQL*Plus, you issue this SELECT statement: SELECT* FROM order; You use this statement to retrieve data from a data table for ().
scores_table<- data.table() ) 访问期中成绩,可写作: scores_table[______________]
scores_table<- data.table() ) 用列号访问第2列数据,可写作: scores_table[______________]
scores_table<- data.table() ) 访问第2,4行数据,可写作: scores_table[______________]
阅读下面的命令连接文件(简称CMD文件)和程序文件: CMD文件: MEMORY { PAGE 0: PROG: origin = 0x1000, length = 0x1000 PAGE 1: DATA: origin = 0x2000, length = 0x1000 } SECTIONS { .text: {} > PROG PAGE 0 .data: {} > DATA PAGE 1 } .data table: .word 1,2,3,4 ; 变量初始化 .text start: STM 0,SWWSR ; 插入0个等待状态 问: (1)MEMORY和SECTIONS的作用各是什么? (2)标号“table”和“start”的地址分别是什么,分别位于程序空间还是数据空间?