I am new to ibm cloudant and I am using the python API for cloudant for my web application.
Is there any way I can retrieve documents from my couch database hosted on IBM cloudant instance using regex on "_id"?
I've read the python-cloudant documentation but I couldn't find anything.
Please help.
Thank you.
If you consider the underlying API, you can use the $regex operator in Cloudant Query. However, it won't use an index, so performance will be pretty dire, as it will scan the whole database. If possible, try arrange your ids such that you can find the subset you need with a range query instead. Given a db that looks like so:
% curl https://skruger.cloudant.com/aaa/_all_docs
{"total_rows":4,"offset":0,"rows":[
{"id":"aaron","key":"aaron","value":{"rev":"1-..."}},
{"id":"adam","key":"adam","value":{"rev":"1-..."}},
{"id":"ben","key":"ben","value":{"rev":"1-..."}},
{"id":"charlie","key":"charlie","value":{"rev":"1-..."}}
]}
we can retrieve all docs with id starting with "a" only,
% curl 'https://skruger.cloudant.com/aaa/_all_docs?startkey="a"&endkey="b"'
{"total_rows":4,"offset":0,"rows":[
{"id":"aaron","key":"aaron","value":{"rev":"1-..."}},
{"id":"adam","key":"adam","value":{"rev":"1-..."}}
]}
Related
I am trying to query an old mongoDB collection in node.js with the native driver.
It uses Legacy UUID as its _id field.
In my code I am using Binary values such as: "2u0kLwUZuEWQvjqOjgQU4g=="
and I want to query the collection with find() operation.
When trying to test it directly with mongoDB I am able to use the following query:
db.getCollection('myCollection').find({_id: BinData(3, "2u0kLwUZuEWQvjqOjgQU4g==")})
to find my item.
But what I need to do is to find multiple items.
So I need to use something like this:
db.getCollection('myCollection').find({_ids: { $in: [BinData(3, "2u0kLwUZuEWQvjqOjgQU4g=="), BinData(3, "3u0kLwUZuEWQvjqOjgQU4g==")...]}})
but it does not seem to work and always returns zero records.
I am not sure why? and what might be the correct way to query multiple Legacy UUIDs?
How we can set read preference for a particular query in MongoDB? Can anyone please share NodeJS example for MongoDB find and aggregate query with the use of read preference? We are using mongoose as an ODM.
Taken from here.
Possible options are:
ReadPreference.PRIMARY
ReadPreference.PRIMARY_PREFERRED
ReadPreference.SECONDARY
ReadPreference.SECONDARY_PREFERRED
ReadPreference.NEAREST
Sample code:
collection.find({}).setReadPreference(new ReadPreference(ReadPreference.SECONDARY_PREFERRED)).toArray(function(err, items) {
// Done reading from secondary if available
})
For library arangodb-spring-data, version 3.2.3, is there any possibility to query for GEO_INTERSECTS functionality using the java api provided by the driver?
Currently I am using an AQL query in my code:
LET areaLiteral = GEO_POLYGON(...)
FOR doc IN MyDocuments
FILTER GEO_INTERSECTS(areaLiteral, doc.geometry)
LIMIT 5 RETURN doc
So far in the official documentation couldn't find anything related to GEO_INTERSECTS, also in this example: https://github.com/arangodb/spring-data-demo#geospatial-queries
I have checked the source code of the driver, but didn't find anything related to keyword "INTERSECTS" which would construct this query behind the scenes.
It is not yet supported, the only supported geospatial queries are Near and Within:
https://www.arangodb.com/docs/3.6/drivers/spring-data-reference-repositories-queries-derived-queries.html#geospatial-queries
https://github.com/DefinitelyTyped/DefinitelyTyped/blob/bb1cc0e143f40f52a8d771e93036fc211df85cfb/types/nano/index.d.ts#L160
i am new to couch db and i know, i can use "fetch" if i want doc in result but i want doc in result based on some conditions when called with start_key and end_key. any help would be appreciated.
fetchRevs(
docnames: BulkFetchDocsWrapper,
params: DocumentFetchParams,
callback?: Callback<DocumentFetchRevsResponse>
): Request;
The fetchRevs endpoint is probably not what you want. I would take a look at the CouchDB API Overview and use:
PUT /mydb to create a database
PUT /mydb/docid to create a document in a database
GET /mydb/_all_docs?include_docs=true to retrieve all the documents
POST /mydb/_find to query the database
These API endpoints are modelled in the Typescript definition file you reference together with URLs that reference the API equivalents.
TLDR
Is there a way to limit queryByExample to a collection in NodeJS?
Problem faced
I have a complex query with some optional fields (i.e. sometimes some search fields will be omitted). So I need to create a query dynamically, e.g. in JSON. QueryByExample seems to be the right tool to use here as it gives me that flexibility to pass a JSON. However my problem is that I would like to limit my search to only one collection or directory.
e.g. I was hoping for something like
searchJSON = {
title: { $word: "test" },
description: { $word: "desc" }
};
//query
db.documents.query(qb.where(
qb.collection("collectionName"),
qb.byExample(searchJSON)
)).result()...
In this case searchJSON could have been built dynamically, for example maybe sometimes title may be omitted from the search.
This doesn't work because the query builder only allows queryByExample to be the only query. But I'd instead like to built a dynamic search query which is limited to a collection or directory.
At present, I think you would have to express the query with QueryBuilder instead of Query By Example using
qb.and([
qb.collection('collectionName'),
qb.word('title', 'test'),
qb.word('description', 'desc')
])
See http://docs.marklogic.com/jsdoc/queryBuilder.html#word
That said, it should be possible for the Node.js API to relax that restriction based on the fixes in MarkLogic 9.0-2
Please file an issue on https://github.com/marklogic/node-client-api