MongoDB – Boise Code Camp 2012

help
show dbs
 
// discuss default IDs and how they work
use exploreid
db.dropDatabase()
 
use exploreid
// db.collection.insert(object)
db.things.insert({'name': 'Daniel Watrous'})
db.things.find()

// build coursetracker database
use coursetracker
db.dropDatabase()
 
use coursetracker
// create student records
db.students.insert({"_id": "john.shore", "name": {"first": "John", "last": "Shore"}, "email": "john.shore@gmail.com", "major": "Electrical Engineering"})
db.students.find()
 
db.students.insert({"_id": "jeff", "name": {"first": "Jeff", "last": "Holland"}, "email": "jeff@yahoo.com", "major": "Business"})
db.students.insert({"_id": "scott", "name": {"first": "Scott", "last": "Mills"}, "email": "scott@hotmail.com", "major": "Humanities/Art"})
db.students.insert({"_id": "rcotter", "name": {"first": "Ray", "last": "Cotter"}, "email": "rcotter@msn.com", "major": "Computer Science"})
db.students.insert({"_id": "lee2331", "name": {"first": "Lee", "last": "Aldwell"}, "email": "lee2331@aol.com", "major": "Graphic Design"})
db.students.find()
// have a look to see that the students collection now exists
show collections
 
// create course records
db.courses.insert({"_id": "HIST-1010", "name": "History of the World 1010", "description": "A bunch of really interesting things that actually happened", "students": [], "ratings": []})
db.courses.find()
 
db.courses.insert({"_id": "ENGCOMP-1010", "name": "English Composition 1010", "description": "If you can't write well, you've got nothing!", "students": [], "ratings": []})
db.courses.insert({"_id": "ART-1050", "name": "Artistic Interpretation 1050", "description": "Discover your inner beholder", "students": [], "ratings": []})
db.courses.find()
 
// create instructor records
db.instructors.insert({"_id": "wally.r.binns", "name": {"first": "Wally", "middle": "r", "last": "Binns"}, "email": "wally.r.binns@ssu.edu", "bio": "I was born in the middle of my mother\"s doctoral dissertation on Faraday Cage isolation. I\"ve been an academic ever since...", "publications": [], "courses": []})
db.instructors.find()
 
db.instructors.insert({"_id": "gerald.waterford.iii", "name": {"first": "Gerald", "last": "Waterford", "suffix": "III"}, "email": "gerald.waterford.iii@ssu.edu", "bio": "My father's father was a great man. My father, not so much. I am restoring the family honor.", "publications": [], "courses": []})
db.instructors.insert({"_id": "kim.b", "name": {"prefix": "Mrs.", "first": "Kim", "last": "Binnley"}, "email": "kim.b@ssu.edu", "bio": "My mother told me 'Don't let those dopes push you around'. My life has been a constant struggle against dopeness ever since. Sigh...", "publications": [], "courses": []})
db.instructors.find().pretty()
// now we can see all three of our collections
show collections

// add some publications
var pub = {"title": "Inverted Celestial Poetry", "source": "http://www.pubcentral.com/poetry/inverted-celestial-poetry"}
pub
// db.collection.update( criteria, objNew, upsert, multi )
db.instructors.update({"_id": "wally.r.binns"}, {$push: {"publications": pub1}}, false, false)
db.instructors.update({"_id": "gerald.waterford.iii"}, {$push: {"publications": {"title": "Grow, grow, little Dandelion", "source": "http://www.hopefulstories.com/my-dandelion"}}}, false, false)
db.instructors.update({"_id": "gerald.waterford.iii"}, {$push: {"publications": {"title": "The teapot and the spoon", "source": "http://www.dishsoap.com/teapot-spoon"}}}, false, false)
 
// now lets assign some courses to instructors
db.courses.find({}, {'_id': 1, 'name': 1})
db.instructors.update({"_id": "kim.b"}, {$push: {"courses": "ART-1050"}}, false, false)
db.instructors.update({"_id": "gerald.waterford.iii"}, {$push: {"courses": "ENGCOMP-1010"}}, false, false)
db.instructors.update({"_id": "gerald.waterford.iii"}, {$push: {"courses": "HIST-1010"}}, false, false)
db.instructors.find().pretty()
 
// now lets add some students to courses
db.courses.update({"_id": "ART-1050"}, {$push: {"students": "scott"}}, false, false)
db.courses.update({"_id": "ART-1050"}, {$push: {"students": "jeff"}}, false, false)
db.courses.update({"_id": "ART-1050"}, {$push: {"students": "rcotter"}}, false, false)
db.courses.update({"_id": "HIST-1010"}, {$push: {"students": "scott"}}, false, false)
db.courses.update({"_id": "HIST-1010"}, {$push: {"students": "john.shore"}}, false, false)
db.courses.update({"_id": "ENGCOMP-1010"}, {$push: {"students": "john.shore"}}, false, false)
db.courses.update({"_id": "ENGCOMP-1010"}, {$push: {"students": "jeff"}}, false, false)
db.courses.update({"_id": "ENGCOMP-1010"}, {$push: {"students": "rcotter"}}, false, false)
db.courses.update({"_id": "ENGCOMP-1010"}, {$push: {"students": "lee2331"}}, false, false)
db.courses.update({"_id": "ENGCOMP-1010"}, {$push: {"students": "scott"}}, false, false)
db.courses.find().pretty()

// find out how many courses each student has
map_number_courses = function() { 
  this.students.forEach(function(value) {
    emit(value, 1);
  });
}
reduce_number_courses = function(key, values) {
    var result = 0;
 
    values.forEach(function(value) {
      result += value;
    });
 
    return result;
}
result = db.courses.mapReduce(map_number_courses, reduce_number_courses, {out: {replace: "numbercourses"}});
show collections
db.numbercourses.find()

// produce a listing of student full name and how many courses he/she is taking
map_course_report_names = function() { 
  emit(this._id, {name: this.name.first+' '+this.name.last, numbercourses: 0});
}
map_course_report_number = function() { 
  this.students.forEach(function(value) {
    emit(value, {name: '', numbercourses: 1});
  });
}
reduce_course_report = function(key, values) {
    var result = {name: '', numbercourses: 0};
 
    values.forEach(function(value) {
      result.numbercourses += value.numbercourses;
      if (result.name === '') {
        result.name = value.name;
      }
    });
 
    return result;
}
result = db.courses.mapReduce(map_course_report_number, reduce_course_report, {out: {replace: "coursereport"}});
result = db.students.mapReduce(map_course_report_names, reduce_course_report, {out: {reduce: "coursereport"}});
show collections
db.coursereport.find()