This question already has answers here:
Querying mongodb from golang using the _id stored in an array
(3 answers)
Find by id with mgo
(1 answer)
Closed 4 years ago.
Here I'm fetching the data from the database mongodb using golang. Suppose I have an Id attribute and i want to receive the data on the basis of this id and it was easy by passing the id attribute in the query like below:-
c.Find(bson.M{"_id": 1}).One(&data)
If the id is given 1. but I have an case that i have find two or more at one time on the basis of the ids that it will returns the array of the ids like "_id":[1,2,3] then How will I retrieve the data from that ids. Can anyone help for if.
EDITED
IS this question solve my problem.
Thanks
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This question already has answers here:
Firestore - get specific fields from document
(4 answers)
Closed 12 days ago.
There is a database named userdetails of three columns name, email, and password. How can I fetch only name from Firebase Firestore? Please give an example.
I have stucked in that thing(fetching of specific data)
As far as I am aware, you can't do that with a server side query. A firebase query would return the DocumentSnapshot.
On the client side you would map that to what you need.
https://firebase.google.com/docs/firestore/query-data/get-data
This question already has answers here:
Firestore - Possible to query by array-not-contains?
(4 answers)
Firestore get documents where value not in array?
(4 answers)
Closed 1 year ago.
I have a firestore collection with many document and all these documents include an array field (called "notFor") with a list of uid. In some cases the array contains only 1 value in some other cases it contains more than 1 value. Example
docA
notFor: "userB", "userC"
docB
notFor: "userB"
docC
notFor: "userA", "userC"
Is there any suggestion on how I could find a document in that collection that does not include "userB"? I basically would like to find docB by excluding all the docs where userC is present
I am writing in flutter however this is not so relevant for this case, I am just interested to understand if I can do something like this with the firestore operators.
thanks!
This question already has answers here:
Test empty string in mongodb and pymongo
(4 answers)
Closed 5 years ago.
I am working on a application built in PHP using MongoDB as a database.
Data is organized across BSON documents into a collection in MongoDB.
I need to retrieve only those documents where field containing string value is non empty value. I searched for functions equivalent to empty and strlen functions belonging to PHP language but did not get any relevant search results.
try this,
$cursor = $collection->find(array("someField" => array('$ne' => null)));
This question already has answers here:
MongoDB - how to query for a nested item inside a collection?
(3 answers)
Closed 9 years ago.
Consider my query to be: {cheese:"Cheddar"} and I have the following collections:
{vegetable:"Lettuce", cheese:"Cheddar"}, {cheese:"Blue"}, {milk:"Chocolate}, {cheese:"Cheddar"}
How do I make a find that returns me all collections that include cheese:Cheddar?
The result would be {vegetable:"Lettuce", cheese:"Cheddar"}, {cheese:"Cheddar"} but right now it fives me just {cheese:"Cheddar"}. From what I investigated I only found tokens to work with arrays.
I do NOT know the name of the property is cheese, nor do I know if there are any other ingredients.
I am looking for a way to get documents from a collection, where the query is included in a field, by the names of the properties in the query and the respective values.
Using db.collection.findOne({cheese:"Cheddar"}) you will get as a result only one document, maybe {cheese:"Cheddar"} or maybe {vegetable:"Lettuce", cheese:"Cheddar"}, the first one that MongoDB finds depending on the _id field. If what you want is getting both, you should use db.collection.find({cheese:"Cheddar"}).
This question already has answers here:
What is the maximum number of parameters passed to $in query in MongoDB?
(4 answers)
Closed 6 years ago.
Was just wondering if there is a limit to Mongodb's $in function?
http://www.mongodb.org/display/DOCS/Advanced+Queries#AdvancedQueries-%24in
I have a collection of users (BIG) and have a smaller subset of ObjectIds stashed somewhere, and I want to select all users (collections) that are in my ObjectIds.
Thanks
Since there's no limit on the number of items in an array as such, you shouldn't have any problem..
For the case when the array is embedded inside a document, you might want to have a look at these:
http://groups.google.com/group/mongodb-user/browse_thread/thread/4a7caeba972aa998?fwc=1
Filtering content based on words
http://groups.google.com/group/mongodb-user/browse_thread/thread/28ae76e5ad5fcfb5