There is more than 40 collections in database I am currently working on.
One of the major key in all the collections is "account".
I need to know all such collections where there is a field called "account".
Is there a query to get or a js script which prints all such collections?
In Oracle I was using :
SELECT * FROM ALL_TAB_COLUMNS WHERE COLUMN_NAME LIKE 'account';
Any inputs is helpful.
Thanks in advance.
The following mongo script will print out all collection names where at least one document contains an account field.
db.getCollectionNames().forEach(function(collname) {
var count = db[collname].find({"account": {$exists: true}}).count();
if (count > 0) {
print(collname);
}
})
Related
I using firebase, nodejs and i have a question how to query field exist some document.
Example :
Collections : users => document : A with field {
....
is_correct: true
}
document : B with field {
.....
}
In my above example , i have two document in collection users. On document A i have field is_correct: true and on document B field is_correct not exist.
My collection users about 15.000 document and it have 50 document contain field is_correct: true
When i write code look like :
await firestore.collection('users').where('is_correct', '==', true).get();
it can get correct me 50 document. But i don't understand it can using index on field is_correct or not ? And it can query best performance ? I understand firebase can't get document if field undefined. It impart in case ? Please help ? Thanks you
For a simple query like
firestore.collection('users').where('is_correct', '==', true)
you don't need to configure any index, Firestore does it automatically.
As you mentioned, only documents where the given field exists can match the query.
And this is the case also for Not-equal (!=) and not-in queries: they exclude documents where the given field does not exist, as explained in the documentation.
Also, note that a field exists when it's set to any value, including an empty string (""), null, and NaN (not a number).
So, in conclusion, if you want to query for documents where is_correct is not true, you need to create this field in these documents with a value different than true.
Hi I have two mongodb collections. The first one returns json data (array) and with the output of this, I want to return documents that match.
When I run Console.log (req.bidder.myBids) I get the following output:
[{"productId":"3798b537-9c7b-4395-9e41-fd0ba39aa984","price":3010},{"productId":"3798b537-9c7b-4395-9e41-fd0ba39aa984","price":3020},{"productId":"4c4bd71c-6664-4d56-b5d3-6428fe1bed19","price":1040},{"productId":"4c4bd71c-6664-4d56-b5d3-6428fe1bed19","price":1050},{"productId":"4c4bd71c-6664-4d56-b5d3-6428fe1bed19","price":1060},{"productId":"4c4bd71c-6664-4d56-b5d3-6428fe1bed19","price":1070},{"productId":"4c4bd71c-6664-4d56-b5d3-6428fe1bed19","price":1090},{"productId":"4c4bd71c-6664-4d56-b5d3-6428fe1bed19","price":1100}]
The productId has duplicates, I want to remove duplicates and then call a routine that finds all the products that match and output as json.
So far I have this code that only outputs one document, but cant figure out how to add the array of productId's and then fetch all corresponding products.
var agencyId = req.body.agencyId;
var productId = req.body.productId;
if (!validate.STRING(agencyId)) {
res.apiError(messages.server.invalid_request);
} else {
dbProduct.find({productId:{$in:['3798b537-9c7b-4395-9e41-fd0ba39aa984','4c4bd71c-6664-4d56-b5d3-6428fe1bed19']}
}).then(dbRes => {
console.log(dbRes);
Updated code and works with hard-wired productId and updated above code. Looking at how to get the array data and transpose replacing the hard-wired productId's
The $in operator is what you want. See the docs here: https://docs.mongodb.com/manual/reference/operator/query/in/
I have multiple checkboxes for different categories of blogs -
And what I want to achieve is that when I select some categories and click on filter, the specified selected blogs would be shown. I used query string parameters or URL parameters to send all the selected checkbox values to the nodejs backend -
query is an array containing all the selected categories
const response = await axios.get(`http://localhost:8000/blog/all?categories=${query}`)
And in the backend -
const cat = req.query.categories;
const all = await blogModel.find({ category: { $in: cat } });
I am passing the cat, which again consists of all the selected categories from the frontend, to $in to find all the matching blogs.
But the issue I am facing is that I am not getting matching blogs, say when I select the 'Science' checkbox and click on the filter I am able to get all the blogs having 'Science' as a category. But when I select say 'Science' & 'Food', I am getting an empty array as output even though I do have blogs of both categories in my MongoDB.
Backend console log of cat when I select 'Science' category -
And when I select 'Science' & 'Food' -
I get an empty array as output instead of all the blogs of 'Science' & 'Food' categories.
To summarize , when i select more than one categories i am getting an empty array instead of the blogs of the selected categories.And when i select only one category then i am able to get the selected blogs.It's not working for multiple categories
I am sure I am missing out on something but don't know what to google to get correct results. I also went through similar StackOverflow questions but I was not able to wrap my head around what needs to be done. I am building a simple blog website for my portfolio & thought of adding this 'filter by category' feature so that I would get to learn on how to filter values from MongoDB using mongoose. Please help me resolve this issue. Thank You.
Edit 1 - This is an example of a document from my collection
Also 'console.log(req.query.categories)' outputs this when i select 'Science' & 'Food' from the above checkbox -
I think you didnt path data as array to mongo query
first split by , and then pass to query
const cat = req.query.categories;
cat = cat.split(",")
const all = await blogModel.find({ category: { $in: cat } });
Yes there seems no issue in your query, make sure you are passing right data to backend like you saved "food" as category in database and searching for "Food" it will return empty array as it is case sensitive.
db.Posts.find({category: { $in:["Food","Gaming"]}})
You can also try this way to fetch
db.Posts.aggregate([{$match:{category: {$in:["cat","dog"]}}}])
const cat = req.query.categories;
var splitcat = cat .split(",");
db.Posts.find({category: { $in:splitcat }})
So I got a small database, It's not going to grow much more and I'm trying to get one document from the db in an API that I implemented in python so that with a given document Id I retrieve the document in the db. However, I find it a little hard to put the user to write a random number from the db. All I require is a function that modifies each document by setting an id field and to Auto-Increment. As I said, it's not going to grow that much and the performance isn't really an issue here.
So far what I've been able to do is this:
var i = 0
db.MyCollection.update({},
{$set : {"new_field":1}},
{upsert:false,
multi:true}
i ++;),
I achieved to set an id field but it sets the same number to each document (the count of every document) So let's say that if the db has 10 docs, it'll set the Id to 10.
Find-and-modify operation returns the document updated (before or after the update depending on returnDocument setting). You can use this with $inc to implement a counter. Ruby example where c is a collection:
irb(main):005:0> c['foo'].insert_one(counter:true,count:1)
=> #<Mongo::Operation::Insert::Result:0x8040 documents=[{"n"=>1, "opTime"=>{"ts"=>#<BSON::Timestamp:0x00005609f260b7e0 #seconds=1594961771, #increment=2>, "t"=>1}, "electionId"=>BSON::ObjectId('7fffffff0000000000000001'), "ok"=>1.0, "$clusterTime"=>{"clusterTime"=>#<BSON::Timestamp:0x00005609f260b538 #seconds=1594961771, #increment=2>, "signature"=>{"hash"=><BSON::Binary:0x8060 type=generic data=0x0000000000000000...>, "keyId"=>0}}, "operationTime"=>#<BSON::Timestamp:0x00005609f260b290 #seconds=1594961771, #increment=2>}]>
irb(main):011:0> c['foo'].find_one_and_update({counter:true},{'$inc':{count:1}})
=> {"_id"=>BSON::ObjectId('5f112f6b2c97a6281f63f575'), "counter"=>true, "count"=>1}
irb(main):012:0> c['foo'].find_one_and_update({counter:true},{'$inc':{count:1}})
=> {"_id"=>BSON::ObjectId('5f112f6b2c97a6281f63f575'), "counter"=>true, "count"=>2}
irb(main):013:0> c['foo'].find_one_and_update({counter:true},{'$inc':{count:1}})
=> {"_id"=>BSON::ObjectId('5f112f6b2c97a6281f63f575'), "counter"=>true, "count"=>3}
irb(main):014:0> c['foo'].find_one_and_update({counter:true},{'$inc':{count:1}})
=> {"_id"=>BSON::ObjectId('5f112f6b2c97a6281f63f575'), "counter"=>true, "count"=>4}
Why not just use this logic? Instead of updating all via one query, just launch multiple queries one by one? Mongo will do it pretty fast, even if you have >1M docs in database (according to your phrase: I got a small database) because pre-builded index on _id field.
this is a javasript code, but I guess, you'll understand the logic of it
let all_documents = db.MyCollection.find({});
for (let i = 0; i < all_documents.length; i++) {
db.MyCollection.update({_id: all_documents[i]._id }, {$set : {"new_field": i}}, {upsert:false})
}
Here My query
model.db.aggregate([{$lookup: {from: 'orders', localField: 'prod_id',
foreignField: '_id', as: 'Col'}},{$match:{$text:
{$search:'Sale'}}}).exec((err,data) => {console.log(data);}]);
but error showing "$match with $text is only allowed as the first pipeline !!"
I just want to lookup many collection then only I have to match'Search' in all the data what we joined(lookup) before.
mongoDb version: 4.0
Anybody have an idea ? need Help !
Thanks !!
These all are my Example collections:
collection 1 ->
organization ={'_id':ObjectId("5b110a7b84a0442030a1e9cf"),'Org_name':'dhoni institute','Estd':'1945'}
collection 2 -> players= {'_id':ObjectId("45110a7b84a3542030a1e9cf"),'_name':'Ms dhoni','Org_id' = ObjectId("5b110a7b84a0442030a1e9cf") }
I am searching the text string 'dhoni' in Db..then I want all the documents which contains word 'dhoni' from these collections.
How to do ?
db.players.aggregate([{$match:{$text:{$search:'dhoni'}}},
{
$lookup{from:'organization',localField:'_id',foreignField:'Org_id',as:'org'}
}
]).exec((err,data) => {}
this is my code It only matches the string from 'players' collection .I need matched 'players' collection documents as well as 'Organization' collection documents.
I cannot create new collection because after loopup data may be a huge data so
I cannot inserting new large data every time search
How to match the string after lookup ?
As explained in official mongodb documentation,
$text performs a text search on the content of the fields indexed with a text index.
But indexes are reachable only by the first stage of an aggregation query. That's the reason of your error message.
The only way i see for you to use $text/$search is to perform your aggregation (without match stage), adding an $out stage to output to a new collection, create a text index on that collection, and perform your find query with $text/$search criteria.
Hope it helps.