Class Notes of CSCI 513 Advanced Database Systems (Fall 2025)
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SELECT DISTINCT  s.student_id, class, major
  FROM  student s, enrollment e
  WHERE  s.student_id = e.student_id;

for ( i = 1; i<=|s|, i++ ) {
  for ( j = 1; j <=|e|; j++ ) {
    if ( i.id = j.id ) {
      print( i.id, j.c, j.m );
    }
  }
}



shell> ls -all note.txt

-rwxr-xr-x.  1 wen.chen.hu domain users   181 Jul 12 04:48 note.txt*

 111101101 = 755 = 111 101 101
 rwxrwxrwx         --- --- ---
                    7   5   5

O: Owner permission (you)
G: Group members permission
E: Everyone else permission (including the Web)

shell> chmod 755 note.txt

sqlplus wenchen/ @xe