I have a collection called "Products". I want to access and change an attribute called "screenShots" inside the collection.
This code didn't work with me
screenshotsURLS: function(sshots) {
check(sshots, [String]);
Products.update({},{$set:{screenShots:sshots}});
console.log(sshots);
}
when i console.log the sshots, i can see that the array exists, but the update function isn't working
how do i set the screenShots attribute inside the Product collection to whatever value passed in "screenshotsURLS" function?
For that you have to update the mongodb document.
THis is how you can update the doc in meteor.
collectionName.update(
<query>,
<update>,
{
upsert: <boolean>,
multi: <boolean>,
writeConcern: <document>
}
)
In your your case collectionName is Products and field is screenShots.
So for doing this. Your query will be
sshots
Products.update({},{$set:{screenShots:sshots}}) (Be careful this will update all of your doc)
For selecting doc update use the query like.
Products.update({name:'yourProductName'},{$set:{screenShots:sshots}})
For more about update a please check this link.
Related
In DynamoDb, is it possible to do a conditional put and return the old item if there already was a matching item?
I would like something like the following to create the row if the user does not already exist, and if it does exist, I want it to return the old item (with whatever name was there before). I.e., insert item if new, else just read existing item.
await documentClient.put({
TableName: 'table',
Item: {
userId: 'user0',
name: 'smith',
},
ConditionExpression: 'attribute_not_exists(userId)',
});
Is this possible to do in one call?
Sort of.
If you use UpdateItem it will create or update the item. It only updates the fields that have changed however, so if your fields have not changed, then no update will be made. It will also create the item if you do not have it.
Using Conditional Items for this will return an ErrorCode if the condition fails ConditionalCheckFailedException - which would require an additional operation.
(I don't use the javascript SDK that much, more in python, so I'm not sure this is the correct version/page but here is some documentation:
https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB.html#updateItem-property )
I want to create Firestore documents if they don't exist - if they do exist, skip them (don't update).
Here's the flow
var arrayOfRandomIds = [array of 500 random numbers];
for (var id of arrayOfRandomIds)
{
var ref = db.collection("tickets").doc(id);
batch.set(ref, {name: "My name", location: "Somewhere"}, { merge: true });
}
batch.commit();
I just want to know, would this overwrite any existing documents if they exist? I don't want anything overwritten, just skipped.
Thanks.
I think you can use security rules to accomplish that. That way you won't be charged for an additional document read to see if it already exists.
service cloud.firestore {
match /databases/{database}/documents {
match /tickets/{id} {
allow create;
}
}
}
Meanwhile there is a "create but don't overwrite" function.
Assuming you are using JavaScript here is the reference: https://googleapis.dev/nodejs/firestore/latest/DocumentReference.html#create
Here is the corresponding example code from the docs:
let documentRef = firestore.collection('col').doc();
documentRef.create({foo: 'bar'}).then((res) => {
console.log(`Document created at ${res.updateTime}`);
}).catch((err) => {
console.log(`Failed to create document: ${err}`);
});
Using .create() instead of .set() should do the trick for you without relying on security rules for application logic.
Firestore doesn't have a native "create but don't overwrite" operation. Here are the only available operations:
update: only change the contents of an existing document
set without merge: create or overwrite
set with merge: create or update if exists
Instead of a batch, what you can do instead is perform a transaction that checks to see if the document exists, then creates it conditionally if it does not already exist. You will have to write that logic inside your transaction handler.
I want to create Firestore documents if they don't exist - if they do exist, skip them (don't update).
In that case, you should check if a particular document actually exists in a collection, right before the write operation takes place. If it does not exist, create it, otherwise take no action.
So you should simply use set() function, without passing merge: true.
I want to create Firestore documents if they don't exist - if they do exist, skip them (don't update).
Here's the flow
var arrayOfRandomIds = [array of 500 random numbers];
for (var id of arrayOfRandomIds)
{
var ref = db.collection("tickets").doc(id);
batch.set(ref, {name: "My name", location: "Somewhere"}, { merge: true });
}
batch.commit();
I just want to know, would this overwrite any existing documents if they exist? I don't want anything overwritten, just skipped.
Thanks.
I think you can use security rules to accomplish that. That way you won't be charged for an additional document read to see if it already exists.
service cloud.firestore {
match /databases/{database}/documents {
match /tickets/{id} {
allow create;
}
}
}
Meanwhile there is a "create but don't overwrite" function.
Assuming you are using JavaScript here is the reference: https://googleapis.dev/nodejs/firestore/latest/DocumentReference.html#create
Here is the corresponding example code from the docs:
let documentRef = firestore.collection('col').doc();
documentRef.create({foo: 'bar'}).then((res) => {
console.log(`Document created at ${res.updateTime}`);
}).catch((err) => {
console.log(`Failed to create document: ${err}`);
});
Using .create() instead of .set() should do the trick for you without relying on security rules for application logic.
Firestore doesn't have a native "create but don't overwrite" operation. Here are the only available operations:
update: only change the contents of an existing document
set without merge: create or overwrite
set with merge: create or update if exists
Instead of a batch, what you can do instead is perform a transaction that checks to see if the document exists, then creates it conditionally if it does not already exist. You will have to write that logic inside your transaction handler.
I want to create Firestore documents if they don't exist - if they do exist, skip them (don't update).
In that case, you should check if a particular document actually exists in a collection, right before the write operation takes place. If it does not exist, create it, otherwise take no action.
So you should simply use set() function, without passing merge: true.
I'm having a problem right now in firebase. Where I try to delete/remove a specific array data. What is the best way to do it? Ps. I'm just new in firebase/flutter.
My database structure:
Data that i'm trying to remove in my database structure(Highlighted one):
First create a blank list and add element in the list which you want to remove then Update using below method
Note : For this method you need the documennt id of element you want to delete
var val=[]; //blank list for add elements which you want to delete
val.add('$addDeletedElements');
Firestore.instance.collection("INTERESTED").document('documentID').updateData({
"Interested Request":FieldValue.arrayRemove(val) })
Update:
Much has changed in the API, although the concept is the same.
var collection = FirebaseFirestore.instance.collection('collection');
collection
.doc('document_id')
.update(
{
'your_field': FieldValue.arrayRemove(elementsToDelete),
}
);
Firestore does not provide a direct way to delete an array item by index. What you will have to do in this case is read the document, modify the array in memory in the client, then update the new contents of the field back to the document. You can do this in a transaction if you want to make the update atomic.
This will help you to add and remove specific array data in could_firestore.
getPickUpEquipment(EquipmentEntity equipment) async{
final equipmentCollection = fireStore.collection("equipments").doc(equipment.equipmentId);
final docSnap=await equipmentCollection.get();
List queue=docSnap.get('queue');
if (queue.contains(equipment.uid)==true){
equipmentCollection.update({
"queue":FieldValue.arrayRemove([equipment.uid])
});
}else{
equipmentCollection.update({
"queue":FieldValue.arrayUnion([equipment.uid])
});
}
}
Example
I have an issue of knowing when to add or update an entry to a Firebase Firestore database.
Using doc_ref.set will add a document if it does not exist. It will also override all of a documents fields if it already exists and set is called.
Using doc_ref.update will update fields of a document if the document exists. If the document does not exist, nothing happens.
How do I add a new field to a document if the field does not currently exist, or update the field if it does exist? I could read the database and check if the field exists, and then use either set or update, but surely there is an easier way?
What you're looking for is the merge option in the set operation. From the documentation on setting a document:
var cityRef = db.collection('cities').doc('BJ');
var setWithMerge = cityRef.set({
capital: true
}, { merge: true });
If you're not sure whether the document exists, pass the option to merge the new data with any existing document to avoid overwriting entire documents.
I had similar problem, but I wanted to update array field using FieldValue.arrayUnion, FieldValue.arrayRemove. Therefore could not use set/merge.
To avoid checking if document exists before update (costs 1 read), I wrapped update statement with try/catch and check for error code 5 (NOT FOUND). In this case, set value instead of update.
Code example:
try {
await docRef.update({
arrayField: admin.firestore.FieldValue.arrayUnion(...dates),
});
} catch (error) {
if (error.code === 5) {
// Error: 5 NOT_FOUND: no entity to update:
await docRef.set({
arrayField: dates,
});
}
}