Getting Started With MongoDB and C++

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cmake -G "Visual Studio 17 2022" -A x64 -S "C:\Repos\mongo-c-driver-1.23.0" -B "C:\Repos\mongo-c-driver-1.23.0\cmake-build"

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cmake --build . --config RelWithDebInfo --target install

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cmake .. -G "Visual Studio 17 2022" -A x64 -DCMAKE_CXX_STANDARD=17 -DCMAKE_CXX_FLAGS="/Zc:__cplusplus /EHsc" -DCMAKE_PREFIX_PATH=C:\mongo-c-driver -DCMAKE_INSTALL_PREFIX=C:\mongo-cxx-driver

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cmake --build . --config RelWithDebInfo --target install

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#include <mongocxx/client.hpp>
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#include <bsoncxx/builder/stream/document.hpp>
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#include <bsoncxx/json.hpp>
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#include <mongocxx/uri.hpp>
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#include <mongocxx/instance.hpp>
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#include <algorithm>
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#include <iostream>
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#include <vector>
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using namespace std;
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std::string getEnvironmentVariable(std::string environmentVarKey)
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{
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	char* pBuffer = nullptr;
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	size_t size = 0;
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	auto key = environmentVarKey.c_str();
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	// Use the secure version of getenv, ie. _dupenv_s to fetch environment variable.
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	if (_dupenv_s(&pBuffer, &size, key) == 0 && pBuffer != nullptr)
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	{
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		std::string environmentVarValue(pBuffer);
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		free(pBuffer);
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		return environmentVarValue;
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	}
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	else
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	{
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		return "";
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	}
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}
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auto mongoURIStr = getEnvironmentVariable("MONGODB_URI");
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static const mongocxx::uri mongoURI = mongocxx::uri{ mongoURIStr };
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// Get all the databases from a given client.
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vector<string> getDatabases(mongocxx::client& client)
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{
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	return client.list_database_names();
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}
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int main()
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{
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    // Create an instance.
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    mongocxx::instance inst{};
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    mongocxx::options::client client_options;
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    auto api = mongocxx::options::server_api{ mongocxx::options::server_api::version::k_version_1 };
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    client_options.server_api_opts(api);
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    mongocxx::client conn{ mongoURI, client_options}
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     auto dbs = getDatabases(conn);
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     for (auto db : dbs)
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     {
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         cout << db << endl;
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      }
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      return 0;
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}

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// Create a new collection in the given database.
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void createCollection(mongocxx::database& db, const string& collectionName)
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{
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	db.create_collection(collectionName);
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}
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// Create a document from the given key-value pairs.
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bsoncxx::document::value createDocument(const vector<pair<string, string>>& keyValues)
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{
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	bsoncxx::builder::stream::document document{};
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	for (auto& keyValue : keyValues)
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	{
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		document << keyValue.first << keyValue.second;
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	}
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	return document << bsoncxx::builder::stream::finalize;
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}
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// Insert a document into the given collection.
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void insertDocument(mongocxx::collection& collection, const bsoncxx::document::value& document)
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{
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	collection.insert_one(document.view());
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}

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// Print the contents of the given collection.
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void printCollection(mongocxx::collection& collection)
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{
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	// Check if collection is empty.
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	if (collection.count_documents({}) == 0)
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	{
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		cout << "Collection is empty." << endl;
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		return;
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	}
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	auto cursor = collection.find({});
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	for (auto&& doc : cursor)
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	{
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		cout << bsoncxx::to_json(doc) << endl;
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	}
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}
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// Find the document with given key-value pair.
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void findDocument(mongocxx::collection& collection, const string& key, const string& value)
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{
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	// Create the query filter
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	auto filter = bsoncxx::builder::stream::document{} << key << value << bsoncxx::builder::stream::finalize;
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	//Add query filter argument in find
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	auto cursor = collection.find({ filter });
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	for (auto&& doc : cursor)
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	{
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          cout << bsoncxx::to_json(doc) << endl;
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	}
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}

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// Update the document with given key-value pair.
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void updateDocument(mongocxx::collection& collection, const string& key, const string& value, const string& newKey, const string& newValue)
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{
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	collection.update_one(bsoncxx::builder::stream::document{} << key << value << bsoncxx::builder::stream::finalize,
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		bsoncxx::builder::stream::document{} << "$set" << bsoncxx::builder::stream::open_document << newKey << newValue << bsoncxx::builder::stream::close_document << bsoncxx::builder::stream::finalize);
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}

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// Delete a document from a given collection.
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void deleteDocument(mongocxx::collection& collection, const bsoncxx::document::value& document)
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{
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	collection.delete_one(document.view());
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}

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// ********************************************** I/O Methods **********************************************
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// Input student record.
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void inputStudentRecord(mongocxx::collection& collection)
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{
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	string name, rollNo, branch, year;
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	cout << "Enter name: ";
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	cin >> name;
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	cout << "Enter roll number: ";
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	cin >> rollNo;
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	cout << "Enter branch: ";
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	cin >> branch;
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	cout << "Enter year: ";
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	cin >> year;
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	insertDocument(collection, createDocument({ {"name", name}, {"rollNo", rollNo}, {"branch", branch}, {"year", year} }));
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}
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// Update student record.
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void updateStudentRecord(mongocxx::collection& collection)
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{
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	string rollNo, newBranch, newYear;
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	cout << "Enter roll number: ";
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	cin >> rollNo;
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	cout << "Enter new branch: ";
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	cin >> newBranch;
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	cout << "Enter new year: ";
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	cin >> newYear;
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	updateDocument(collection, "rollNo", rollNo, "branch", newBranch);
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	updateDocument(collection, "rollNo", rollNo, "year", newYear);
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}
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// Find student record.
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void findStudentRecord(mongocxx::collection& collection)
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{
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	string rollNo;
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	cout << "Enter roll number: ";
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	cin >> rollNo;
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	findDocument(collection, "rollNo", rollNo);
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}
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// Delete student record.
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void deleteStudentRecord(mongocxx::collection& collection)
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{
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	string rollNo;
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	cout << "Enter roll number: ";
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	cin >> rollNo;
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	deleteDocument(collection, createDocument({ {"rollNo", rollNo} }));
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}
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// Print student records.
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void printStudentRecords(mongocxx::collection& collection)
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{
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	printCollection(collection);
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}
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// ********************************************** Main **********************************************
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int main()
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{
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     if(mongoURI.to_string().empty())
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    {
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	cout << "URI is empty";
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	return 0;
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    }
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    // Create an instance.
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    mongocxx::instance inst{};
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    mongocxx::options::client client_options;
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    auto api = mongocxx::options::server_api{ mongocxx::options::server_api::version::k_version_1 };
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    client_options.server_api_opts(api);
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    mongocxx::client conn{ mongoURI, client_options};
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	const string dbName = "StudentRecords";
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	const string collName = "StudentCollection";
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	auto dbs = getDatabases(conn);
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	// Check if database already exists.
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	if (!(std::find(dbs.begin(), dbs.end(), dbName) != dbs.end()))
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	{
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		// Create a new database & collection for students.
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conn[dbName];
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	}
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	auto studentDB = conn.database(dbName);
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	auto allCollections = studentDB.list_collection_names();
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	// Check if collection already exists.
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	if (!(std::find(allCollections.begin(), allCollections.end(), collName) != allCollections.end()))
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	{
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		createCollection(studentDB, collName);
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	}
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	auto studentCollection = studentDB.collection(collName);
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	// Create a menu for user interaction
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	 int choice = -1;
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	 do while (choice != 0)
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	 {
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		 //system("cls");
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		 cout << endl << "**************************************************************************************************************" << endl;
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		 cout << "Enter 1 to input student record" << endl;
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		 cout << "Enter 2 to update student record" << endl;
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		 cout << "Enter 3 to find student record" << endl;
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		 cout << "Enter 4 to delete student record" << endl;
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		 cout << "Enter 5 to print all student records" << endl;
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		 cout << "Enter 0 to exit" << endl;
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		 cout << "Enter Choice : "; 
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		 cin >> choice;
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		 cout << endl;
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		 switch (choice)
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		 {
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		 case 1:
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			 inputStudentRecord(studentCollection);
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			 break;
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		 case 2:
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			 updateStudentRecord(studentCollection);
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			 break;
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		 case 3:
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			 findStudentRecord(studentCollection);
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			 break;
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		 case 4:
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			 deleteStudentRecord(studentCollection);
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			 break;
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		 case 5:
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			 printStudentRecords(studentCollection);
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			 break;
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		 case 0:
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			 break;
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		 default:
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			 cout << "Invalid choice" << endl;
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			 break;
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		 }
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	 } while (choice != 0);
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	 return 0;
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}