i have my unreal project that must read out some BSON document data into a map.
right now i'm able to load that file and print it out with the following code :
void AMyActor::BeginPlay()
{
Super::BeginPlay();
std::ifstream input( filePath , std::ios::binary );
std::vector<unsigned char> buffer(std::istreambuf_iterator<char>(input), {});
bson_t* doc{ bson_new_from_data(buffer.data(),buffer.size()) };
char *str;
if( doc != nullptr )
{
UE_LOG(LogTemp,Warning,TEXT( "Success" ));
str = bson_as_json(doc, NULL);
FString fstr = FString(UTF8_TO_TCHAR(str));
UE_LOG(LogTemp, Warning, TEXT("BSON Output: %s"), *fstr);
}
}
and this is here is where i want to store it :
class Databases
{
std::map<std::string,DatabaseBase> _dictionary;
explicit Databases(const std::map<std::string, DatabaseBase>& dictionary)
: _dictionary(dictionary)
{
}
};
so what i'm looking for is to create a new instance of Databases and initialize "_dictionary" with the content of the bson document.
i'm actually looking for this into the libbson document : http://mongoc.org/libbson/current/bson_t.html
but without success...anyone can help me?
thank's in advance
PS: i'm under unreal but i have linked the libbson library
Update:
since i have to provide how my json file looks like, and DatabaseBase looks like
JSON :
{
"_dictionary" : [ {
"_classID" : "CC00",
"_dictionary" : [ {
"k" : "sample_key",
"v" : ["ACH_00"]
}, {
"k" : "sample_index",
"v" : ["0"]
}]
}, {
"_classID" : "CC01",
"_dictionary" : [ {
"k" : "sample_key",
"v" : ["ACH_01"]
}, {
"k" : "sample_index",
"v" : ["1"]
}]
}]
}
DatabaseBase :
class DatabaseBase
{
public:
DatabaseBase() = default;
std::string sample_key;
int sample_index;
};
Breaking out nlohmann::json:
using nlohmann::json;
std::map<std::string, DatabaseBase> dictionaries;
json input = json::from_bson(buffer);
for (auto& obj : input["_dictionary"]) {
auto name = obj["_classID"];
auto key = obj["_dictionary"][0]["v"][0];
auto idx = stoi(obj["_dictionary"][1]["v"][0].get<std::string>());
auto db = DatabaseBase{key, idx};
dictionaries[name] = db;
}
Databases dbs{dictionaries};
output: (from my debugger)
(lldb) p dbs
(Databases) $0 = {
_dictionary = size=2 {
[0] = {
first = "CC00"
second = (sample_key = "ACH_00", sample_index = 0)
}
[1] = {
first = "CC01"
second = (sample_key = "ACH_01", sample_index = 1)
}
}
}
I'm building app with Ionic and angulfire2 and I'm trying to join multiple references from firebase by using the object key.
Database looks following:
{
"achievements" : {
"200" : {
"authorId" : "nGSlhjaDRKh8XdrgxcusU0wdiHN2",
"description" : "I did it"
}
},
"challengeAchievements" : {
"100" : {
"200" : true
}
},
"challenges" : {
"100" : {
"name" : "test challenge"
},
"101" : {
"name" : "test challenge 2"
}
},
"users" : {
"nGSlhjaDRKh8XdrgxcusU0wdiHN2" : {
"email" : "user1#test.com"
},
"wBMX8WOHIpM7dEkzj0hM19OPMbs1" : {
"email" : "user2#test.com"
}
}
}
I would like to join all this data together so that from challenges you get achievements, and from achievements you get the user data.
Currently I'm able to get the achievement details, but not the user data. My provider looks like this at the moment:
getChallengeAchievements(challengeKey) {
return this.rtdb.list(`/challengeAchievements/${challengeKey}`)
.map(achievements => achievements.map((achievement) => {
if (achievement.key)
achievement.details = this.getAchievementDetails(achievement.key);
achievement.user = this.getAchievementUserDetails(achievement.details.authorId);
return achievement;
}));
}
getAchievementDetails(achievementKey?: string): Observable<any> {
if (achievementKey)
return this.rtdb.object(`/achievements/${achievementKey}`);
}
getAchievementUserDetails(authorId?: string): Observable<any> {
if (authorId)
return this.rtdb.object(`/users/${authorId}`);
else console.log('Not found');
}
How should I structure the authorId query in this function? If I use static value in
achievement.details.authorId('nGSlhjaDRKh8XdrgxcusU0wdiHN2')
I'm able to receive the data.
Solved it by subscribing to the first join "achievement.details" and obtaining the user data from there.
getChallengeAchievements(challengeKey) {
return this.rtdb.list(`/challengeAchievements/${challengeKey}`)
.map(achievements => achievements.map((achievement) => {
if (achievement.key)
achievement.details = this.getAchievementDetails(achievement.key);
achievement.details.subscribe(
details => {
achievement.user = this.getAchievementUserDetails(details.authorId);
})
return achievement;
}));
}
I'm using Poco library for C++ code
Here is an example of the json tree I have to parse
{
"name" : "actionToDo",
"description" : "",
"version" : "1",
"parameters" : {
"inputDirectory" : "string",
"workingDir" : "string",
"tempDir" : "string",
"size" : "integer"
}
}
The amount of data into "parameters" field can change.
I have to put all items into a map
Here my code today
std:: map<std::string, std::string> output;
Poco::JSON::Parser sparser;
Poco::Dynamic::Var result = sparser.parse(jsonStr);
Poco::JSON::Object::Ptr object = result.extract<Poco::JSON::Object::Ptr>();
Poco::DynamicStruct ds = *object;
Poco::Dynamic::Var collection(ds["parameters"]);
if (collection.isStruct())
{
LOG("STRUCT"); //it's logged !!
}
for (Poco::Dynamic::VarIterator it = collection.begin(); it != collection.end(); ++it)
{
LOG_F("item : %s", it->toString()); //never logged
//here I would like to have something like
//output[it->first()] = it->second();
}
And the output I got
14:13:00'900 : : [Notice] : STRUCT
14:13:00'900 : : [Critical] : Exception : Exception: Unable to load Run from file :
/opt/.../file.json Exception:
Unable to parse field 'parameters' or its children
Invalid access: Not a struct.
The "Unable to parse field 'parameters' or its children" is generated by a catch below but the "Invalid access: Not a struct." comes from Poco
use for collection variable DynamicStruct instead of Var
Poco::DynamicStruct collection = ds["parameters"].extract<Poco::DynamicStruct>();
for (auto it = collection.begin(); it != collection.end(); ++it)
{
LOG_F("item : %s", it->second.toString().c_str());
}
How can I "refresh" the data in rows inside a table? I know, that the table is refreshed, when the model is getting changed. But the problem is, that the rows are created by a factory method. The code for the rows looks like this:
formatter : function(text, id) {
if (text != null && id != null) {
if (this.getProperty("showId")) {
return text + " ( " + id + " )";
} else {
return text;
}
}
return "";
So, when I click on a button "hide ID" the property is getting changed and the table should be refreshed so that the content is built new. How can I do this? I checked the method .refresh() but this didn't work.
EDIT:
This is my column with the factory function:
columns : [ new sap.ui.table.Column({
label : "XYZ( ID )",
filterProperty : "SHORT_TEXT",
template : new sap.m.Label().bindProperty("text", {
parts : [ {
path : "SHORT_TEXT",
type : new sap.ui.model.type.String()
}, {
path : "ID",
type : new sap.ui.model.type.String()
} ],
formatter : function(text, id) {
if (text != null && id != null) {
if (this.getProperty("showId")) {
return text + " ( " + id + " )";
} else {
return text;
}
}
return "";
}.bind(this)
})
})
This is the method, which changes the property:
onShowHideIdRequest : function(oControlEvent) {
if (oControlEvent.getParameter("pressed")) {
this.setProperty("showId", true);
sap.ui.getCore().byId("oShowHideIdButton").setIcon("sap-icon://show");
} else {
this.setProperty("showId", false);
sap.ui.getCore().byId("oShowHideIdButton").setIcon("sap-icon://hide");
}
sap.ui.getCore().byId("oTreeTable").rerender();
},
And the the property looks like this inside my component:
metadata : {
properties : {
showId : {
type : "boolean",
defaultValue : true
}
},
The "oTreeTable" ID refers to a sap.ui.tableTreeTable
I thought for a few days this all works fine, I don't know what's no wrong ...
First of all, the method you have written is formatter not the factory method. There is a difference between formatter and factory method. Formatter is used to return the value of a property of ui5 control based on some conditions or evaluation where as factory method is used to bind aggregations
In MongoDB, is it possible to update the value of a field using the value from another field? The equivalent SQL would be something like:
UPDATE Person SET Name = FirstName + ' ' + LastName
And the MongoDB pseudo-code would be:
db.person.update( {}, { $set : { name : firstName + ' ' + lastName } );
The best way to do this is in version 4.2+ which allows using the aggregation pipeline in the update document and the updateOne, updateMany, or update(deprecated in most if not all languages drivers) collection methods.
MongoDB 4.2+
Version 4.2 also introduced the $set pipeline stage operator, which is an alias for $addFields. I will use $set here as it maps with what we are trying to achieve.
db.collection.<update method>(
{},
[
{"$set": {"name": { "$concat": ["$firstName", " ", "$lastName"]}}}
]
)
Note that square brackets in the second argument to the method specify an aggregation pipeline instead of a plain update document because using a simple document will not work correctly.
MongoDB 3.4+
In 3.4+, you can use $addFields and the $out aggregation pipeline operators.
db.collection.aggregate(
[
{ "$addFields": {
"name": { "$concat": [ "$firstName", " ", "$lastName" ] }
}},
{ "$out": <output collection name> }
]
)
Note that this does not update your collection but instead replaces the existing collection or creates a new one. Also, for update operations that require "typecasting", you will need client-side processing, and depending on the operation, you may need to use the find() method instead of the .aggreate() method.
MongoDB 3.2 and 3.0
The way we do this is by $projecting our documents and using the $concat string aggregation operator to return the concatenated string.
You then iterate the cursor and use the $set update operator to add the new field to your documents using bulk operations for maximum efficiency.
Aggregation query:
var cursor = db.collection.aggregate([
{ "$project": {
"name": { "$concat": [ "$firstName", " ", "$lastName" ] }
}}
])
MongoDB 3.2 or newer
You need to use the bulkWrite method.
var requests = [];
cursor.forEach(document => {
requests.push( {
'updateOne': {
'filter': { '_id': document._id },
'update': { '$set': { 'name': document.name } }
}
});
if (requests.length === 500) {
//Execute per 500 operations and re-init
db.collection.bulkWrite(requests);
requests = [];
}
});
if(requests.length > 0) {
db.collection.bulkWrite(requests);
}
MongoDB 2.6 and 3.0
From this version, you need to use the now deprecated Bulk API and its associated methods.
var bulk = db.collection.initializeUnorderedBulkOp();
var count = 0;
cursor.snapshot().forEach(function(document) {
bulk.find({ '_id': document._id }).updateOne( {
'$set': { 'name': document.name }
});
count++;
if(count%500 === 0) {
// Excecute per 500 operations and re-init
bulk.execute();
bulk = db.collection.initializeUnorderedBulkOp();
}
})
// clean up queues
if(count > 0) {
bulk.execute();
}
MongoDB 2.4
cursor["result"].forEach(function(document) {
db.collection.update(
{ "_id": document._id },
{ "$set": { "name": document.name } }
);
})
You should iterate through. For your specific case:
db.person.find().snapshot().forEach(
function (elem) {
db.person.update(
{
_id: elem._id
},
{
$set: {
name: elem.firstname + ' ' + elem.lastname
}
}
);
}
);
Apparently there is a way to do this efficiently since MongoDB 3.4, see styvane's answer.
Obsolete answer below
You cannot refer to the document itself in an update (yet). You'll need to iterate through the documents and update each document using a function. See this answer for an example, or this one for server-side eval().
For a database with high activity, you may run into issues where your updates affect actively changing records and for this reason I recommend using snapshot()
db.person.find().snapshot().forEach( function (hombre) {
hombre.name = hombre.firstName + ' ' + hombre.lastName;
db.person.save(hombre);
});
http://docs.mongodb.org/manual/reference/method/cursor.snapshot/
Starting Mongo 4.2, db.collection.update() can accept an aggregation pipeline, finally allowing the update/creation of a field based on another field:
// { firstName: "Hello", lastName: "World" }
db.collection.updateMany(
{},
[{ $set: { name: { $concat: [ "$firstName", " ", "$lastName" ] } } }]
)
// { "firstName" : "Hello", "lastName" : "World", "name" : "Hello World" }
The first part {} is the match query, filtering which documents to update (in our case all documents).
The second part [{ $set: { name: { ... } }] is the update aggregation pipeline (note the squared brackets signifying the use of an aggregation pipeline). $set is a new aggregation operator and an alias of $addFields.
Regarding this answer, the snapshot function is deprecated in version 3.6, according to this update. So, on version 3.6 and above, it is possible to perform the operation this way:
db.person.find().forEach(
function (elem) {
db.person.update(
{
_id: elem._id
},
{
$set: {
name: elem.firstname + ' ' + elem.lastname
}
}
);
}
);
I tried the above solution but I found it unsuitable for large amounts of data. I then discovered the stream feature:
MongoClient.connect("...", function(err, db){
var c = db.collection('yourCollection');
var s = c.find({/* your query */}).stream();
s.on('data', function(doc){
c.update({_id: doc._id}, {$set: {name : doc.firstName + ' ' + doc.lastName}}, function(err, result) { /* result == true? */} }
});
s.on('end', function(){
// stream can end before all your updates do if you have a lot
})
})
update() method takes aggregation pipeline as parameter like
db.collection_name.update(
{
// Query
},
[
// Aggregation pipeline
{ "$set": { "id": "$_id" } }
],
{
// Options
"multi": true // false when a single doc has to be updated
}
)
The field can be set or unset with existing values using the aggregation pipeline.
Note: use $ with field name to specify the field which has to be read.
Here's what we came up with for copying one field to another for ~150_000 records. It took about 6 minutes, but is still significantly less resource intensive than it would have been to instantiate and iterate over the same number of ruby objects.
js_query = %({
$or : [
{
'settings.mobile_notifications' : { $exists : false },
'settings.mobile_admin_notifications' : { $exists : false }
}
]
})
js_for_each = %(function(user) {
if (!user.settings.hasOwnProperty('mobile_notifications')) {
user.settings.mobile_notifications = user.settings.email_notifications;
}
if (!user.settings.hasOwnProperty('mobile_admin_notifications')) {
user.settings.mobile_admin_notifications = user.settings.email_admin_notifications;
}
db.users.save(user);
})
js = "db.users.find(#{js_query}).forEach(#{js_for_each});"
Mongoid::Sessions.default.command('$eval' => js)
With MongoDB version 4.2+, updates are more flexible as it allows the use of aggregation pipeline in its update, updateOne and updateMany. You can now transform your documents using the aggregation operators then update without the need to explicity state the $set command (instead we use $replaceRoot: {newRoot: "$$ROOT"})
Here we use the aggregate query to extract the timestamp from MongoDB's ObjectID "_id" field and update the documents (I am not an expert in SQL but I think SQL does not provide any auto generated ObjectID that has timestamp to it, you would have to automatically create that date)
var collection = "person"
agg_query = [
{
"$addFields" : {
"_last_updated" : {
"$toDate" : "$_id"
}
}
},
{
$replaceRoot: {
newRoot: "$$ROOT"
}
}
]
db.getCollection(collection).updateMany({}, agg_query, {upsert: true})
(I would have posted this as a comment, but couldn't)
For anyone who lands here trying to update one field using another in the document with the c# driver...
I could not figure out how to use any of the UpdateXXX methods and their associated overloads since they take an UpdateDefinition as an argument.
// we want to set Prop1 to Prop2
class Foo { public string Prop1 { get; set; } public string Prop2 { get; set;} }
void Test()
{
var update = new UpdateDefinitionBuilder<Foo>();
update.Set(x => x.Prop1, <new value; no way to get a hold of the object that I can find>)
}
As a workaround, I found that you can use the RunCommand method on an IMongoDatabase (https://docs.mongodb.com/manual/reference/command/update/#dbcmd.update).
var command = new BsonDocument
{
{ "update", "CollectionToUpdate" },
{ "updates", new BsonArray
{
new BsonDocument
{
// Any filter; here the check is if Prop1 does not exist
{ "q", new BsonDocument{ ["Prop1"] = new BsonDocument("$exists", false) }},
// set it to the value of Prop2
{ "u", new BsonArray { new BsonDocument { ["$set"] = new BsonDocument("Prop1", "$Prop2") }}},
{ "multi", true }
}
}
}
};
database.RunCommand<BsonDocument>(command);
MongoDB 4.2+ Golang
result, err := collection.UpdateMany(ctx, bson.M{},
mongo.Pipeline{
bson.D{{"$set",
bson.M{"name": bson.M{"$concat": []string{"$lastName", " ", "$firstName"}}}
}},
)