Lab 3 – additional tips compiled by Reza Soltanpoor
Record == Document
Table == Collection
———————-
https://docs.mongodb.com/manual/tutorial/install-mongodb-on-windows/
https://docs.mongodb.com/manual/mongo/
https://docs.mongodb.com/getting-started/shell/query/
————
simple starting instructions:
—————————–
show dbs
use $DB
show collections
————
ROBOMONGO or MongoDB Shell!
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use dbsystems
db.staff.insert({_id: “e16161”, FirstName: “John”, LastName: “Do”,
roles: [
{ courseID: “COSC2406”, position: “Lecturer”, hours: 2} ,
{ courseID: “COSC2407”, position: “Lecturer”, hours: 2}
]})
use dbsystems
db.student.insert({FirstName: “Fred”, LastName: “Zhang”, Age: 24, StudentNumber: “s1234”})
db.student.insert({FirstName: “Kim”, LastName: “Jones”, Age: 23, StudentNumber: “s4567”})
db.student.insert({FirstName: “Ann”, LastName: “Ng”, Age: 20, StudentNumber: “s6789”})
==========
db.$COLLECTION.find() == db[“$COLLECTION”].find() == SELECT * FROM $TABLE // table == collection
db.$COLLECTION.find().pretty()
db.$COLLECTION.findOne()
some useful parameters inside the “find()” method:
————————————————–
{
nested fields with DOT NOTATION access:
{
db.student.find( {“FirstName” : “Kim”} )
db.student.find( {“FirstName” : “Kim”} ).pretty()
==========
use dbsystems
db.studentCourse.insert({Student: “s1234”, Course: “COSC2406”, Semester: 1})
db.studentCourse.insert({Student: “s1234”, Course: “COSC1127”, Semester: 1})
db.studentCourse.insert({Student: “s1234”, Course: “COSC2110”, Semester: 2})
db.studentCourse.insert({Student: “s4567”, Course: “COSC2406”, Semester: 1})
db.studentCourse.insert({Student: “s6789”, Course: “COSC2406”, Semester: 1})
db.studentCourse.insert({Student: “s6789”, Course: “COSC2110”, Semester: 2})
===========
db.studentCourse.find( {“Course”: “COSC2406” , “Semester”: 1} ).pretty()
———–
https://docs.mongodb.com/getting-started/shell/update/
https://docs.mongodb.com/manual/reference/operator/update/
https://docs.mongodb.com/manual/aggregation/
https://docs.mongodb.com/manual/reference/sql-aggregation-comparison/
———————————————————————-
—- combining two collections “student” and “studentCourse” using the “lookup” aggregate function —-
db.student.aggregate([
{
$lookup: {
from: “studentCourse”,
localField: “StudentNumber”,
foreignField: “Student”,
as: “courseInfo”
}
}
]).pretty()
—– using the “$out” param of the “aggregate” function ——
db.student.aggregate([
{
$lookup: {
from: “studentCourse”,
localField: “StudentNumber”,
foreignField: “Student”,
as: “info”
}
},
{
$out: “courseInfo”
}
])
db.courseInfo.find( {“info.Course” : “COSC2110”} )
===========
Performance Analysis:
———————
ops = [
{
op: “findOne”,
ns: “test.students”,
query: {student_id: “s1234”}
} ,
{
op: “findOne”,
ns: “test.students”,
query: {student_id: “s4567”}
},
{
op: “findOne”,
ns: “test.students”,
query: {student_id: “s6789”}
}
]
—–
for ( var x = 1; x <= 128; x *= 2) { res = benchRun( { parallel : x , seconds : 5 , ops : ops } ); print( "threads: " + x + "\t queries/sec: " + res.query ); } ---- info on the benchRun ---- https://github.com/mongodb/mongo/wiki/JavaScript-Benchmarking-Harness