I have this code, What I am trying to do is create a match and then add the match id to the property "playedMatches" in the player table.
My code creates the match then I add the ID of that created match to the array for "playedMatches" in the player table, everything works fine. However, when I want to push the second played match ID to the array, it deletes all the items in the array and replaces it for the new one created.
In MongoDB I would use the $push Update Operator. Is there something similar I can use for Dynamo DB?
I have also tried with createSet and I get errors every time.
What am I doing wrong?
This is the table structure:
id: xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxx
img:
name: john doe
playedMatches: [xxxxx-xxxxx-xxxx-xxxx-xxxxx]
I want push new id's into playedMatches
const matchId = ['987654321'];
const duplicatedId = '987654321';
const putDataParams = {
TableName: table,
Key: {
id,
},
UpdateExpression: 'set playedMatches = list_append(playedMatches, :matchId)',
ConditionExpression: 'not contains (playedMatches, :duplicatedId)',
ExpressionAttributeValues: {
':matchId': matchId,
':duplicatedId': duplicatedId,
},
ReturnValues: 'UPDATED_NEW',
};
Thanks a lot!
Related
i'm having trouble with node & knex.js
I'm trying to build a mini blog, with posts & adding functionality to add multiple tags to post
I have a POST model with following properties:
id SERIAL PRIMARY KEY NOT NULL,
name TEXT,
Second I have Tags model that is used for storing tags:
id SERIAL PRIMARY KEY NOT NULL,
name TEXT
And I have many to many table: Post Tags that references post & tags:
id SERIAL PRIMARY KEY NOT NULL,
post_id INTEGER NOT NULL REFERENCES posts ON DELETE CASCADE,
tag_id INTEGER NOT NULL REFERENCES tags ON DELETE CASCADE
I have managed to insert tags, and create post with tags,
But when I want to fetch Post data with Tags attached to that post I'm having a trouble
Here is a problem:
const data = await knex.select('posts.name as postName', 'tags.name as tagName'
.from('posts')
.leftJoin('post_tags', 'posts.id', 'post_tags.post_id')
.leftJoin('tags', 'tags.id', 'post_tags.tag_id')
.where('posts.id', id)
Following query returns this result:
[
{
postName: 'Post 1',
tagName: 'Youtube',
},
{
postName: 'Post 1',
tagName: 'Funny',
}
]
But I want the result to be formated & returned like this:
{
postName: 'Post 1',
tagName: ['Youtube', 'Funny'],
}
Is that even possible with query or do I have to manually format data ?
One way of doing this is to use some kind of aggregate function. If you're using PostgreSQL:
const data = await knex.select('posts.name as postName', knex.raw('ARRAY_AGG (tags.name) tags'))
.from('posts')
.innerJoin('post_tags', 'posts.id', 'post_tags.post_id')
.innerJoin('tags', 'tags.id', 'post_tags.tag_id')
.where('posts.id', id)
.groupBy("postName")
.orderBy("postName")
.first();
->
{ postName: 'post1', tags: [ 'tag1', 'tag2', 'tag3' ] }
For MySQL:
const data = await knex.select('posts.name as postName', knex.raw('GROUP_CONCAT (tags.name) as tags'))
.from('posts')
.innerJoin('post_tags', 'posts.id', 'post_tags.post_id')
.innerJoin('tags', 'tags.id', 'post_tags.tag_id')
.where('posts.id', id)
.groupBy("postName")
.orderBy("postName")
.first()
.then(res => Object.assign(res, { tags: res.tags.split(',')}))
There are no arrays in MySQL, and GROUP_CONCAT will just concat all tags into a string, so we need to split them manually.
->
RowDataPacket { postName: 'post1', tags: [ 'tag1', 'tag2', 'tag3' ] }
The result is correct as that is how SQL works - it returns rows of data. SQL has no concept of returning anything other than a table (think CSV data or Excel spreadsheet).
There are some interesting things you can do with SQL that can convert the tags to strings that you concatenate together but that is not really what you want. Either way you will need to add a post-processing step.
With your current query you can simply do something like this:
function formatter (result) {
let set = {};
result.forEach(row => {
if (set[row.postName] === undefined) {
set[row.postName] = row;
set[row.postName].tagName = [set[row.postName].tagName];
}
else {
set[row.postName].tagName.push(row.tagName);
}
});
return Object.values(set);
}
// ...
query.then(formatter);
This shouldn't be slow as you're only looping through the results once.
I try to update an item in dynamodb by adding a condition, without passing the key in the parameters.
And as soon as my condition is true update. Is it possible to do this?
Below an example of an item:
{
"id" : "bcc2f32e-305e-4469-88e2-463724b5c6a9",
"name" : "toto",
"email" : "toto#titi.com"
}
Where email is unique for items.
I tested this code and it works :
const name= "updateName";
const params = {
TableName: MY_TABLE,
Key: {
id
},
UpdateExpression: 'set #name = :name',
ExpressionAttributeNames: { '#name': 'name' },
ExpressionAttributeValues: { ':name': name },
ReturnValues: "ALL_NEW"
}
dynamoDb.update(params, (error, result) => {
if (error) {
res.status(400).json({ error: 'Could not update Item' });
}
res.json(result.Attributes);
})
But i want to do something like this (replace the Key by conditionExpression):
const params = {
TableName: MY_TABLE,
UpdateExpression: 'set #name = :name',
ConditionExpression: '#email = :email',
ExpressionAttributeNames: {
'#name': 'name',
'#email': 'email'
},
ExpressionAttributeValues: {
':name': name,
':email': email
},
ReturnValues: "ALL_NEW"
}
dynamoDb.update(params, (error, result) => {
if (error) {
res.status(400).json({ error: 'Could not update User' });
}
res.json(result.Attributes);
})
But this code doesn't work.
Any ideas?
You cannot update an item in DynamoDB without using the entire primary key (partition key, and sort key if present). This is because you must specify exactly one record for the update. See the documentation here.
If you want to find an item using a field that is not the primary key, then you can search using a scan (potentially slow and expensive) or by using a Global Secondary Index (GSI) on that field. Either of these methods requires that you do a separate request to find the item in question, and then use its primary key to perform the update.
It sounds like you want to do an update that waits for a condition. That's not how DynamoDb works; it cannot wait for anything (except consistency, I suppose, but that's somewhat different). What you can do is make a request with a condition, and if it fails the condition (returning immediately), make the request again later. If you do this you'll need to be careful to backoff appropriately, or you might end up making a lot of requests very quickly.
The key is a required parameter when doing updates; the condition expression can be used in addition to providing the key, but can't be used instead of the key.
Also, I am not sure you fully understand what the conditionExpression is for - its not like the 'where' clause in an SQL update statement (i.e. update mytable set name='test' where email='myemail.com'.
Instead, logically the conditionExpression in an update would be more like:
update mytable set name='test' where key='12345' but only if quantity >0 - for example,
i.e. you are telling dynamodb the exact key of the record you want updated, and once it finds it it uses the condition expression to determine if the update should proceed - i.e. find the record with id=12345, and change the name to 'test', only of the quantity is greater than 0.
It does not use the conditionExpression to find records to update.
I tried to find a way to copy/clone instances in Sequelize but without success. Is there any way to do it with a built-in function or without? What I want is to simply copy rows in the database and the new item should have only a different id.
There is no such direct function for that , What you can do is :
Fetch the object that you want to clone/copy
Remove Primary Key from it
Make a new entry from it
model.findOne({ //<---------- 1
where : { id : 1 } ,
raw : true })
.then(data => {
delete data.id; //<---------- 2
model.create(data); //<---------- 3
})
As said, there is no such direct function for that (thanks Vivek)
If you find useful, place the following code on your model class:
async clone() {
let cData = await THISISMYMODEL.findOne({
where: { id: this.id},
raw: true,
});
delete cData.id;
return await THISISMYMODEL.create(data);
}
Take into account that "THISISMYMODEL" should be the model class defined and "id" the primary key attribute used.
Also take into account the use of Foreign Keys (relations with other models), it will use the same keys. Otherwise you should clone those instances too.
You may need to update the name though or some other field to identify it as a copy,
const data = await model.findOne({ where: {id: 1}, raw: true, attributes: { exclude: ['id'] } });
data.name = data.name + '(copy)';
const newRecord = await model.create(data);
Write a Model.create(data) function inside Model.js and call this function from inside of a loop, as many times you need it will create the copy of the same data.
I am using Aqua, a website and user system built using Hapi/React/Flux. http://jedireza.github.io/aqua/
I have a new text field in AccountsForm.jsx called "job". It has correctly added to the db as seen below:
{ _id: ObjectId("569a9fdf9b4fbb060a3f956a"), name: { first: "Dylan", middle: "James", last: "Thomas" }, timeCreated: ISODate("2016-01-16T19:54:07.334Z"), user: { id: "569a9fdf9b4fbb060a3f9569", name: "daylightdylan" }, job: "Web Dev" }
During onDispatcherAction > GET_ACCOUNT_SETTINGS_RESPONSE in account/stores/Account.js I can see that it is setting the this.state values using the values from action.data., which contains "name" and "timeCreated" however my new "job" variable does not exist. Where do I define/add my new variable to action.data so that it is available? I am new to this and I am completely lost!
this.handleResponseErrors(action.data);
this.state.hydrated = true;
this.state.name = action.data.name; ////exists
this.state.job = action.data.job; ////does not exist
this.state.timeCreated = action.data.timeCreated; ////exists
this.emitChange();
Thanks in advance
The fieldsAdapter in the API handler needs to be updated with the new variable that is to be added. For example:
var fields = Account.fieldsAdapter('user name timeCreated');
With new variable added:
var fields = Account.fieldsAdapter('user name job timeCreated');
The fieldsAdapter is a helper method that creates a fields object suitable to use with MongoDB queries.
mongoose scheme:
var restsSchema = new Schema({
name: String,
menu: mongoose.Schema.Types.Mixed
});
simplfied document:
{
name: "Dominos Pizza",
menu:{
"1":{
id: 1,
name: "Plain Pizza",
soldCounter: 0
},
"2":{
id: 2,
name: "Pizza with vegetables",
soldCounter: 0
}
}
}
I'm trying to update the soldCounter when given a single/array of "menu items" (such as "1" or "2" objects in the above document) as followed:
function(course, rest){
rest.markModified("menu.1");
db.model('rests').update({_id: rest._id},{$inc: {"menu.1.soldCounter":1}});
}
once this will work i obviously will want to make it more generic, something like: (this syntax is not working but demonstrate my needs)
function(course, rest){
rest.markModified("menu." + course.id);
db.model('rests').update({_id: rest._id},{$inc:{"menu.+"course.id"+.soldCounter":1}});
}
any one can help with this one?
I looked for an answer but couldn't find nothing regarding the 3rd level.
UPDATE:
Added id to the ducument's subDocument
I think you want add all ids into sub-document, one way you can do as following.
Rest.find({_id: rest._id}, function(err, o) {
// add all ids into sub-document...
Object.keys(o.menu).forEach(function(key) {
o.menu[key].id = key;
});
o.save(function(err){ ... });
});
It seems you want to operate the key in query, I am afraid you cannot do it in this way.
Please refer to the following questions.
Mongodb - regex match of keys for subobjects
MongoDB Query Help - query on values of any key in a sub-object