db.test1.insertOne(
   {
      "StudentId" :1,
      "StudentName" : "Joseph Connor"
   }
)

db.test1.find()

show dbs
db.dropDatabase()
show dbs

// remove tinker
use tinker
db.test1.find()
doc = {
      "StudentId" :1,
      "StudentName" : "Joseph Connor"
}
doc
if (db.test1.find(doc).count() == 0) { db.test1.insertOne(doc) }
db.test1.find()
if (db.test1.find(doc).count() == 0) { db.test1.insertOne(doc) }
db.test1.find()

doc2 = {
	"StudentId" :1
}

db.test1.find(doc2)
db.test1.find()
// remove tinker
show dbs
db.dropDatabase()
show dbs
// create index
db.test1.createIndex( 
	{ "StudentId": 1 }, // 1st argument: fields in the index; 1: true
	{ unique: true } )  // 2nd argument: property of the index
doc = {
      "StudentId" :1,
      "StudentName" : "Joseph Connor"
}
doc
db.test1.insertOne(doc)
db.test1.insertOne(doc)

db.test1.insertMany([
   {   "StudentId" :2,
      "GPA": 3.72
   },
   {   "StudentId" :3,
      "GPA": 1.69
   },
   {
      "BCAssetId": "78c22fc6-5dec-11ec-bf63-0242ac130002",
      "BCAssetType": "BCAssetTypeMetadata",
      "BCAssetName": "BCAssetTypeMetadata: MBSEModel",
      "ForBCAssetType": "MBSEModel",
      "Version": {
         "Version": "1.0",
         "Subversion": null,
         "StartTime": "2019-01-13T07:23:13+06:00"
      }
   }
])
db.test1.find()

mongorestore --archive="toyu-db.gz" --gzip --nsFrom='toyu.*' --nsTo='toyu.*'

db.student.find()

db.student.find(
	{}, // query
    { "_id": 0 }  // projection; 0: false
)


db.student.find(
	{}, // query
    { "_id": 0,  "studentId": 1, "major": 1
	}  // projection; 0: false
)

db.student.find(
	{}, // query
    { "_id": 0,  "stuId": 1, "major": 1
	}  // projection; 0: false
)

db.student.find(
	{"major": "CSCI" }, // query
    { "_id": 0,  "stuId": 1, "major": 1
	}  // projection; 0: false
)

db.student.find(
	{"major": "CSCI", "minor":"CINF" }, // query
    { "_id": 0,  "stuId": 1, "major": 1, "minor":1
	}  // projection; 0: false
)

// db.collection.find(query, projection, options)
// query: {}
// projection: { "fname": 1, "lname":1, "_id": 0 }  
// Executing db.collection.find() in mongosh, returns a cursoe, automatically iterates the cursor to display up to the first 20 documents. Type it to continue iteration.
result = db.student.find({},
   { "fname": 1, "lname":1, "_id": 0 }  
).toArray()

// May not always work as toArray() returns a promise,
// which may not be ready for use.
result.forEach((x,i) => console.log('student #' + String(i) + ': ' + x["fname"] + ' ' + x["lname"]))

result.forEach((x,i) => console.log('student #' + String(i+1) + ': ' + x["fname"] + ' ' + x["lname"]))

//Show the names and credits (ach) of students majoring in 'CSCI' and having 40 or more credits.

// SQL .. WHERE major = 'CSCI' AND ach >= 40 
db.student.find(
   { "major": "CSCI", "ach" : {$gte: 40} },
   { "fname": 1, "lname":1, "major": 1, "ach":1, "_id": 0 }  
)

result = db.student.find(
   { "major": "CSCI", "ach" : {$gte: 40} },: []
   { "fname": 1, "lname":1, "major": 1, "ach":1, "_id": 0 }  
).toArray()

// Show the first name and last name of students with a first name starting with a L or B, case insensitive.
db.student.find(
	//  a first name starting with a L or B, case insensitive.
	//  fname needs to match a regular expression ($regex):
	//    Regular expression is ^[lb] (regex is embedded by two /'s.
	//	^ match a position: beginning position
	// [lb]: a character class
   { "fname": { $regex: /^[lb]/, $options: "i" } },
   { "fname": 1, "lname":1, "_id": 0 }  
)

use toyu
//
// [1] Show the stuId, classId and grade of all enrollment with a grade of "B+", "B", or "B-" in the following manner.
//  SQL:  ... WHERE grade IN ("B+", "B", "B-")

db["enroll"].find(
	{  "grade": {"$in": ["B+", "B", "B-"] }},
	{	"stuId": 1, "classId": 1, "grade": 1, "_id": 0,  }	
)

// [2] Show the name, rank, and department code of every CINF or ITEC faculty member in the following manner.
// SQL: SELECT CONCAT(f.fname, ' ', s.lname) AS faculty,
//			f.deptCode, f.`rank`
//		FROM faculty AS f
//		WHERE f.deptCode IN ("CINF", "ITEC");

db.faculty.find(
	{  "deptCode": {"$in": ["CINF", "ITEC"] }},  // query
	{	"faculty": {"$concat": ["$fname", " ", "$lname"]}, 
        "deptCode": 1, "rank": 1, "_id": 0,  }	// projection
)

db.faculty.find()

db.faculty.find(
	{  "deptCode": {"$in": ["CINF", "ITEC"] }},  // query
	{	"faculty": {"$concat": ["$fname", " ", "$lname"]}, 
        "deptCode": 1, "rank": 1, "_id": 0,  }	// projection
)

db.faculty.find(
	{  "deptCode": {"$in": ["CINF", "ITEC"] }},  // query
	{	"faculty": {"concat": ["$fname", " ", "$lname"]}, 
        "deptCode": 1, "rank": 1, "_id": 0,  }	// projection
)
//
//  [3] Show the classId and the number of all students enrolled in the class in the following manner.
//

db["enroll"].aggregate(
	[	
		{ $group: { "_id": "$classId", "count": {$count: {}}} },
		{ $project: { "classId": "$_id" , "Number of students": "$count",  "_id": 0 }}
	]
)

//
// [4] Show the name, and deptCode of all faculty members who have the substring "an" in their first names or last names in JSON form in the following manner.
//

// query: 	{ "$or": [ {"fname": { $regex: /an/, $options: "i" }},
//				{ "lname": { $regex: /an/, $options: "i" }}]},

result = db.faculty.find(
	{ "$or": [ {"fname": { $regex: /an/, $options: "i" }},
		{ "lname": { $regex: /an/, $options: "i" }}]},
	{ "faculty": {"$concat": ["$fname", " ", "$lname"]},
						"deptCode": 1,  "_id": 0}
)

result = db.faculty.find(
	{ "$or": [ {"fname": { $regex: /an/, $options: "i" }},
	{ "lname": { $regex: /an/, $options: "i" }}]},
	{ "faculty": {"$concat": ["$fname", " ", "$lname"]},
						"deptCode": 1,  "_id": 0}
).toArray()

db.faculty.find()
db.faculty.aggregate([
    {"$group" : {_id:"$deptCode", "count":{$sum:1}}}
])

db.faculty.aggregate(
   [  
      { $group: { "_id": "$deptCode", "count": {$sum:1}} },
      { $project: { "deptCode": "$_id" , "num_faculty": "$count",  "_id": 0}}
   ]
)

db.faculty.aggregate(
   [  
      { $group: { "_id": "$deptCode", "count": {$sum:1}} },
      { $project: { "deptCode": "_id" , "num_faculty": "count",  "_id": 0}}
   ]
)

db["enroll"].aggregate(
	[
		{ $group: { "_id": "$classId", "count": {$count: {}}} },
		{ $project: { "classId": "$_id" , "Number of students": "$count",  "_id": 0 }}
	]
)