I have a graphQL schema like this:
type Post {
id: String!
title: String!
content: String!
user: User!
}
type Query {
allPosts: [Post!]
singlePost(id: String!): Post!
}
type User {
name: String!
posts: [Post!]
}
The dynamo DataSource handles queries. In the query below, the user will be handled with a different resolver because it depends on different GSI.
query MyQuery {
allPosts {
content
title
user{
name
}
}
}
allPosts resolver looks like this:
{
"version" : "2017-02-28",
"operation" : "Query",
"query" : {
"expression" : "#t = :sk",
"expressionNames" : {
"#t": "type"
},
"expressionValues" : {
":sk": $util.dynamodb.toDynamoDBJson("post")
}
},
"index" : "GSI",
"select" : "ALL_ATTRIBUTES"
}
The resolver for user in the Post type is:
{
"version" : "2017-02-28",
"operation" : "Query",
"query" : {
"expression" : "PK = :pk AND SK = :sk",
"expressionValues" : {
":pk": "NEED TO ACCESS THE Partition KEY FROM ALL_POSTS",
":sk": $util.dynamodb.toDynamoDBJson("profile")
}
},
"select" : "ALL_ATTRIBUTES"
}
I need to access the partition key from the post object in each iteration to fetch the user of a specific id, just like the author resolver in this code (https://github.com/benawad/graphql-n-plus-one-example/blob/master/src/index.js):
const resolvers = {
Book: {
author: async parent => {
const author = await knex("users")
.select()
.where("id", parent.authorId)
.first();
return author;
}
},
Query: {
books: async () => {
const books = await knex("books")
.select()
.limit(10);
return books;
}
}
};
I've found the answer finally, the required object is stored in $ctx.source. All I had to do is to change the user resolver to this (Provided the result object have PK inside it):
{
"version" : "2017-02-28",
"operation" : "Query",
"query" : {
"expression" : "PK = :pk AND SK = :sk",
"expressionValues" : {
":pk": $util.dynamodb.toDynamoDBJson($ctx.source.PK),
":sk": $util.dynamodb.toDynamoDBJson("profile")
}
},
"select" : "ALL_ATTRIBUTES"
}
The $context.source references the parent object of the current field that’s being resolved. In this example, $ctx.source.PK refers to the individual Post object, which is then used for the query expression. ($context and $ctx are same). It works exactly like the parent argument in the apollo-server framework.
I'm trying to get a record from a GSI and I'm stucked.
API Schema:
type DriverInfos {
id: String!
status: Int
lastLat: Float
lastLng: Float
idDriver: String # GSI
}
type Query {
getDriverInfosByDriver(idDriver: String): DriverInfos
}
Resolver :
{
"version" : "2017-02-28",
"operation" : "Query",
"index" : "idDriver-index",
"query" : {
## Provide a query expression. **
"expression": "#idDriver = :idDriver",
"expressionNames" : {
"#idDriver" : "idDriver"
},
"expressionValues" : {
":idDriver" : {
"S" : "${ctx.args.idDriver}"
}
}
}
}
Query :
query getDriverInfosByDriver{
getDriverInfosByDriver(idDriver: "1")
{
idDriver
status
lastLat
lastLng
}
}
Return :
{
"data": {
"getDriverInfosByDriver": {
"idDriver": null,
"status": null,
"lastLat": null,
"lastLng": null
}
}
}
GSI is well activated : Name : "idDriver-index" - PartitionKey : idDriver (String)
Try with other ids : 2, 3, ...
It seems that it comes from the resolver. I tried with different resolver but it always return an error.
Thank you in advance for your answers.
The issue is that a Query operation always returns a set of results not just one. If you want to leave your query type like this:
type Query {
getDriverInfosByDriver(idDriver: String): DriverInfos
}
then you should to change your response mapping template to this:
#if($ctx.result.items.size() > 0)
$util.toJson($ctx.result.items[0])
#else
null
#end
If instead the getDriverInfosByDriver query should return multiple info objects then you should change your schema to:
type DriverInfo {
id: String!
status: Int
lastLat: Float
lastLng: Float
idDriver: String # GSI
}
type DriverInfoConnection {
items: [DriverInfo]
nextToken:String
}
type Query {
getDriverInfosByDriver(idDriver: String): DriverInfoConnection
}
You can then leave your response mapping template as the default:
$util.toJson($ctx.result)
and then query it like so
query getDriverInfosByDriver{
getDriverInfosByDriver(idDriver: "1") {
items {
idDriver
status
lastLat
lastLng
}
}
}
I am trying to create a getItem request in AWS Lambda to access DynamoDB like so:
dynamodb.getItem({
TableName: "DataTable",
Key: {
user: {
S: user
},
deleted: {
BOOL: false
}
}
}, function(err, data) {
if (err) return fn(err);
else {
if ('Item' in data) {
fn(null, user);
} else {
fn(null, null); // User not found
}
}
});
It worked fine when I passed the user in as that was the primary key on the table. I added a deleted boolean to create a soft delete on users. But one I added that in the schema errors started to happen as deleted isn't part of the primary key. I want a way to add it as a where clause coming from the relational DB world. How is this done? Thanks. :o)
The getItem cannot be used if the data has to be filtered by any non-key attributes.
I think in the above case, the 'deleted'attribute is a non-key attribute. So, the Query API should be used to filter the data along with key attribute.
Please refer the FilterExpression in the below example.
FilterExpression : 'deleted = :createdate'
(AWS.Request) query(params = {}, callback)
Sample code:-
var params = {
TableName : table,
KeyConditionExpression : 'yearkey = :hkey and title = :rkey',
FilterExpression : 'deleted = :deleted',
ExpressionAttributeValues : {
':hkey' : year_val,
':rkey' : title,
':deleted' : {BOOL : false}
}
};
docClient.query(params, function(err, data) {
if (err) {
console.error("Unable to read item. Error JSON:", JSON.stringify(err,
null, 2));
} else {
console.log("GetItem succeeded:", JSON.stringify(data, null, 2));
}
});
For your use case, the key, filter condition and expression attribute value should be as mentioned below:-
KeyConditionExpression : 'user = :user',
FilterExpression : 'deleted = :deleted',
ExpressionAttributeValues : {
':user' : 'John',
':deleted' : {BOOL : false}
}
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"}}}
}},
)