My use case: i would set a flag ("read" or "unread") in a group of documents with only one request.
My first idea was to send a list of ids using an _update handler but reading docs it seem to work only on one document.
I'm wrong? How to solve this case?
You are correct.
Currently (CouchDB 1.1.0 and to my knowledge the next release, 1.2 also), the only way to modify documents in bulk is to send the literal documents themselves to CouchDB using the CouchDB bulk document API.
In my experience, in practice, this is not a major problem because bulk operations tend to be done with offline tools or else with AJAX operations where there is no noticeable impact to the user experience.
Related
I have been reading docs and articles on pouchdb/couchdb/cloudant. I am not able to create this simple architecture in my head. I need help!
So there are many users on the app. Each user has a separate database (which I read is the approach in pouch/couch/cloudant setup).
Now lets just focus on a single user. This user has some remote data already present on our server(couchdb). He has 3 separate docs stored.
He accesses docs 1 and docs 2 from browser 1. And docs 2 and docs 3 from browser 2.
Content in both the browsers must be in sync.
Should I be using Sync api of pouchdb? But as I read, it sync's the whole database. How can I use this api to sync only a subset of the central database. Is filtered replication answer here?
And also I don't want to push both the docs in a single call. He can access docs as he needs.
What is the correct approach to implement this logic with pouch/couch databases. If you can explain with a little code, that will be great. I just need basic ideas.
Is this kind of problem easily solvable in upcoming releases of CouchDB 2.0 and PouchDB-find.
Thanks a lot!
If you take a look at the PouchDB documentation, you should see the options.doc_ids. This parameter let you setup a replication on certain document ids. In your scenario, this would be solving your problem.
I have a news base that needs to work online and offline. I'm using CouchDB (IBM Cloudant ) and PouchDB to make this sync with the APP.
The problem is that the news is relatively "heavy" for having photos and am having sync problems because the size of the "docs", and does not see any need to synchronize all the news base, will only fill the user's mobile phone with unnecessary records.
I need to sync only some news, approx. five registers. I wonder how can I do this in CouchDB or PouchDB.
I looked in sync + filters documentation but does not answer me the question of the amount of sync docs (or at least did not see if it is possible).
I'm using a view to pull the news.
Since you're using a view to pull the news, you can use limit to limit the number of documents you fetch. You can also use since to determine when you need to fetch the next batch of documents (this will have to be executed periodically to check for the existence of new documents)
If you go down this route and if your app doesn't need need client -> server replication then you could use something lighter than PouchDB do store the documents and other info on the client.
Yes you can, use filtered replication for this: https://pouchdb.com/api.html#filtered-replication
Credits: Nolan Lawson (PouchDB core team).
I need to write into two different mongodb collections using an 'all or nothing' process. Fyi I use NodeJs in my backend side.
As far as I know MongoDb provides atomicity when it comes to a single collection, but it does not when we need to write into multiple collections.
So I'd like to know a way of emulating this a transaction in nodejs/mongodb in order to avoid writing into one collection if the other failed and also getting the possibility of doing a 'roll back' if the second process fails.
Thank you guys!
Starting from version 4.0 MongoDB will add support for multi-document transactions. Transactions in MongoDB will be like transactions in relational databases.
For details visit this link:
https://www.mongodb.com/blog/post/multi-document-transactions-in-mongodb?jmp=community
I wrote a library that implements the two phase commit system mentioned above. It might help in this scenario. Fawn - Transactions for MongoDB
The transactions for multi-document have been introduced in MongoDB 4.0 !!!
https://docs.mongodb.com/manual/core/transactions
In MongoDB (prior to 4.0) there is no way you can fully implement transactions on database level. However, there are some mechanisms which provides some transactions functionality. You can read about them in documentation.
Since MongoDB 4.0, transactions are supported. Very little chage is needed in your current code to support them. There's a new section in the documentation fully dedicated to the subject
I've been able to sync data from my cloudant instance to my nodejs based pouchdb, however I need to setup a secondary search index and therefore I created a view on the couchdb instance however I am unable to see it in my synced pouchdb instance.
I see it in cloudant, in all documents, however after syncing and calling alldocs on pouchdb, it's not there. Also, i'm using the pouchdb-find plugin and I can't reference the secondary index search fields. Of course from pouchdb if if set the secondary index, it works fine.
Am I missing something? Does sync not replicate design docs in PouchDB? If not, what's the best way to create a persistent secondary index?
Any good docs for this? (Nolan....?) Speaking of docs, or support, is there an IRC room or some other live support for couchdb from the user community?
Thanks for your attention,
Paul
pouchdb-find is a reimplementation of Cloudant Query Language, not their search index (which is what I think you're talking about). It's also not done; I've only written about half of the operators. :) You may also want to try the pouchdb-quick-search plugin, which is for full-text search.
In general, the advice I usually give people is to not sync design documents at all – just replicate using a filter to avoid syncing design docs. Then you can create design documents that are optimized for whatever platform you happen to be on (PouchDB, CouchDB, Cloudant, the various PouchDB plugins, etc.).
And yeah, we are usually pretty responsive inside of the IRC channel and on the mailing list, but it's a small operation because we aren't sponsored by Cloudant or Couchbase or anybody. The core PouchDB team are all hobbyists. :)
Maybe this is stupid but, does the user that access couch has the admin role? Only admins can see and edit design documents.
I can't find any information on initalizing a couch db. What's the best method of initializing and creating the map and view functions for couchdb at deployment?
I have a node server which will access a couchdb. Should I just create the http calls necessary to create the proper logic on couchdb from my node server or is there a better way handling the initialization of the db?
EDIT: Also is there any good open source projects that I can take examples from?
I'm not sure your question is clear. Remember that CouchDB is schemaless, so, at startup, there probably isn't anything (ie, documents) on which to base view functions.
If you mean a helper to setup a design document with attachments and the like, in addition to the other answers, have a look at Kanso (http://kan.so). If you're comfortable with Node, you'll find it friendly.
If, on the other hand, you're looking for something to analyze existing docs in a CouchDB and guess at good views, I've haven't come across that yet.
One possibility would be to use erica.