Update assignment3-infs

assignment3-infs

@@ -46,8 +46,6 @@ b. A student named “John Smith” has taken the course “cs530”
 
 let $stud := $doc.("student")[][$$.name = "John Smith"]
 let $tscript := $doc.("transcript")[][$$.co = "CS530"].s
-
-
 return $tscript = $stud.s
 
 c. All students named “John Smith” has taken the course “cs530”
@@ -60,7 +58,6 @@ for $x in $doc("student")[]
 where (every $name in $x.name satisfies $name eq "John Smith"  )
 return $x.s
 )
-
 let $search_classes := $doc("transcript")[][$$.s eq $jsmith_no].co
 for $class in $search_classes
 where $class eq "CS530"
@@ -115,29 +112,42 @@ return $class_w_pre
 
 h. Some courses do not have prerequisites
 
+
 let $course := $doc("course")[].co
 let $prereqs := $doc("prereq")[].co
 return $prereqs = $course
 
 
 i. All classes offered this semester have prerequisites.
 
+let $course := $doc("course")[].co
+let $prereqs := $doc("prereq")[].co
+return $prereqs = $course
+
 j. Some students received only grades “A” or “B” in every course
 they have taken (must appear in Transcripts)
 
 
 k. All students currently involved in classes taught by professor
 Brodsky (instructor = “Brodsky”) major in “CS”
 
+let $brod := $doc("class")[][$$.instructor = "Brodsky"].co
+let $brod_stud := $doc("transcript")[][$$.co = $brod].s
+let $students := $doc("student")[][$$.s = $brod_stud]
+for $student in $students
+where (some $student  in $students satisfies $student.major = "CS")
+return $student.major = "CS"
 
 
 l. Some students who are currently enrolled in classes taught by
 professor Brodsky major in “CS”
 
-let $q2 := $doc.("class")[][$$.instructor = "Brodsky"]
-let $brod_classes := $q2
-let $brod_students := $doc.("transcript")[][$$.co = $brod_classes.co]
-return $brod_students
+let $brod := $doc("class")[][$$.instructor = "Brodsky"].co
+let $brod_stud := $doc("transcript")[][$$.co = $brod].s
+let $students := $doc("student")[][$$.s = $brod_stud]
+for $student in $students
+where (every $student  in $students satisfies $student.major = "CS")
+return $student.major = "CS"
 
 2. Write jsoniq queries to express/compute each of the following sets
 (sequences) of:
@@ -156,7 +166,7 @@ return $doc("student")[][$$.s = $stud].name
 b. All students named “John Smith” who have taken the course
 “cs530” (must be in Transcipts)
 
-//KINDA CORRECT
+// CORRECT
 
 let $q2 := $doc.("student")[][$$.name = "John Smith"]
 let $transcripts := $doc.("transcript")[][$$.s = $q2.s][$$.co = "CS530"]
@@ -171,7 +181,6 @@ d. All students who are enrolled in a class for which they have not
 satisfied all its prerequisites.
 
 
-
 e. All students named “John Smith” who are enrolled in a class for
 which they have not satisfied all its prerequisites.
 
@@ -214,13 +223,17 @@ return $classes.co
 i. All students who received only grades “A” or “B” in every course
 they have taken (must appear in Transcripts)
 
-//NOT CORRECT
+//eh CORRECT
 
 let $students := $doc("student")[].s
-let $transcript := $doc("transcript")[][$$.grade eq "A" or "B"]
-for $x in $students
-where $transcript.s = $x
-return $x
+
+let $A_OR_B :=(
+for $stud in $students
+where (every $grade in $doc("transcript")[].s satisfies  $doc("transcript")[][$$.s = $stud][$$.grade = "A" or $$.grade = "B"])
+return $stud)
+
+return $A_or_B
+
 
 
 j. All CS students who are currently enrolled in a class taught by