I have a collection of product in which I have document like this
"_id" : ObjectId("5acb1dad698eaa7a254c9017"),
"txtProductCode" : "1233A",
"txtModelCode" : "00M",
"txtPartNo" : "00P",
"txtSerialNo" : "00S",
"txtProductName" : "Watch",
"traderId" : ObjectId("5ac5fb29b0f9b3444e6c1ef2")
I want to search a product based on its name and traderId for which I used
db.getCollection('product').find( {$and:[{'txtProductName':"Watch"},{"traderId" : ObjectId("5ac5fb29b0f9b3444e6c1ef2")}]})
its working fine but now if a user have input model no then it shoud use model number also to search for a product if the user have not input the model no then it should without model number
So My question is do I have to use cases like this
if(req.body.modelNo)
db.getCollection('product').find( {$and:[{'txtProductName':"Watch"},{"traderId" : ObjectId("5ac5fb29b0f9b3444e6c1ef2")},{'txtModelCode':"00M"}]})
else
db.getCollection('product').find( {$and:[{'txtProductName':"Watch"},{"traderId" : ObjectId("5ac5fb29b0f9b3444e6c1ef2")}]})
or is there a way to do this without making cases I have to do this for multiple condtions so I am trying not to use cases
Create the query object first then add the extra key with a conditional check. No need to explicitly use the $and operator when specifying a comma separated list of expressions as it's implicitly provided:
let query = {
'txtProductName': 'Watch',
'traderId': ObjectId('5ac5fb29b0f9b3444e6c1ef2')
};
if (req.body.modelNo) query['txtModelCode'] = req.body.modelNo;
db.getCollection('product').find(query);
If using the $and operator, you can push the additional query into an array then use the list for the $and operator:
let andOperator = [
{ 'txtProductName': 'Watch' },
{ 'traderId': ObjectId('5ac5fb29b0f9b3444e6c1ef2') }
];
if (req.body.modelNo) andOperator.push({ 'txtModelCode': req.body.modelNo });
// if (req.body.modelNo) andOperator = [...andOperator, { 'txtModelCode': req.body.modelNo }];
db.getCollection('product').find({ '$and': andOperator });
Well, I would have done this in this way
First, you should send a json of specific from to backend. for example
[{'txtModelCode':"00M"},{'txtPartNo':"AC"},{'Yts':"xyz"}]
OR
[{'txtModelCode':"00M"},{'txtPartNo':"AC"}]
OR
[{'txtModelCode':"00M"}]
This is the payload that you should expect in req.body. And finally you can use it in your find() criteria. Something like
db.getCollection('product').find( {$and:[{'txtProductName':"Watch"},
{"traderId" : ObjectId("5ac5fb29b0f9b3444e6c1ef2")}, ...req.body]})
... is called spread operator. Spread syntax allows an iterable such as an array expression or string to be expanded. Read more about it here
This will make it totally dynamic. Any scaling in collection can directly be used in find criteria. you never have to add extra line of code
Related
I need to make the following query, I have a model in the db that holds a string. for example lets say that's the data:
[{ a : 'test/t' },
{ a : 'test/b' }]
Now I have the following string
var search = 'http://ttt.com/test/t'
I want to make a query which will find all the documents that 'a' property is contained inside the search variable, case insensetive.
All the exmaples I've seen talk about the opposite equation.
You can use the following query for the operation which uses the short for $where. Since this runs in Javascript, expect it to run slowly.
db.coll.find(function () {
var re = new RegExp(this.a.replace("/", "\/"))
return 'http://ttt.com/test/t'.match(re)
});
This is the case: A webshop in which I want to configure which items should be listed in the sjop based on a set of parameters.
I want this to be configurable, because that allows me to experiment with different parameters also change their values easily.
I have a Product collection that I want to query based on multiple parameters.
A couple of these are found here:
within product:
"delivery" : {
"maximum_delivery_days" : 30,
"average_delivery_days" : 10,
"source" : 1,
"filling_rate" : 85,
"stock" : 0
}
but also other parameters exist.
An example of such query to decide whether or not to include a product could be:
"$or" : [
{
"delivery.stock" : 1
},
{
"$or" : [
{
"$and" : [
{
"delivery.maximum_delivery_days" : {
"$lt" : 60
}
},
{
"delivery.filling_rate" : {
"$gt" : 90
}
}
]
},
{
"$and" : [
{
"delivery.maximum_delivery_days" : {
"$lt" : 40
}
},
{
"delivery.filling_rate" : {
"$gt" : 80
}
}
]
},
{
"$and" : [
{
"delivery.delivery_days" : {
"$lt" : 25
}
},
{
"delivery.filling_rate" : {
"$gt" : 70
}
}
]
}
]
}
]
Now to make this configurable, I need to be able to handle boolean logic, parameters and values.
So, I got the idea, since such query itself is JSON, to store it in Mongo and have my Java app retrieve it.
Next thing is using it in the filter (e.g. find, or whatever) and work on the corresponding selection of products.
The advantage of this approach is that I can actually analyse the data and the effectiveness of the query outside of my program.
I would store it by name in the database. E.g.
{
"name": "query1",
"query": { the thing printed above starting with "$or"... }
}
using:
db.queries.insert({
"name" : "query1",
"query": { the thing printed above starting with "$or"... }
})
Which results in:
2016-03-27T14:43:37.265+0200 E QUERY Error: field names cannot start with $ [$or]
at Error (<anonymous>)
at DBCollection._validateForStorage (src/mongo/shell/collection.js:161:19)
at DBCollection._validateForStorage (src/mongo/shell/collection.js:165:18)
at insert (src/mongo/shell/bulk_api.js:646:20)
at DBCollection.insert (src/mongo/shell/collection.js:243:18)
at (shell):1:12 at src/mongo/shell/collection.js:161
But I CAN STORE it using Robomongo, but not always. Obviously I am doing something wrong. But I have NO IDEA what it is.
If it fails, and I create a brand new collection and try again, it succeeds. Weird stuff that goes beyond what I can comprehend.
But when I try updating values in the "query", changes are not going through. Never. Not even sometimes.
I can however create a new object and discard the previous one. So, the workaround is there.
db.queries.update(
{"name": "query1"},
{"$set": {
... update goes here ...
}
}
)
doing this results in:
WriteResult({
"nMatched" : 0,
"nUpserted" : 0,
"nModified" : 0,
"writeError" : {
"code" : 52,
"errmsg" : "The dollar ($) prefixed field '$or' in 'action.$or' is not valid for storage."
}
})
seems pretty close to the other message above.
Needles to say, I am pretty clueless about what is going on here, so I hope some of the wizzards here are able to shed some light on the matter
I think the error message contains the important info you need to consider:
QUERY Error: field names cannot start with $
Since you are trying to store a query (or part of one) in a document, you'll end up with attribute names that contain mongo operator keywords (such as $or, $ne, $gt). The mongo documentation actually references this exact scenario - emphasis added
Field names cannot contain dots (i.e. .) or null characters, and they must not start with a dollar sign (i.e. $)...
I wouldn't trust 3rd party applications such as Robomongo in these instances. I suggest debugging/testing this issue directly in the mongo shell.
My suggestion would be to store an escaped version of the query in your document as to not interfere with reserved operator keywords. You can use the available JSON.stringify(my_obj); to encode your partial query into a string and then parse/decode it when you choose to retrieve it later on: JSON.parse(escaped_query_string_from_db)
Your approach of storing the query as a JSON object in MongoDB is not viable.
You could potentially store your query logic and fields in MongoDB, but you have to have an external app build the query with the proper MongoDB syntax.
MongoDB queries contain operators, and some of those have special characters in them.
There are rules for mongoDB filed names. These rules do not allow for special characters.
Look here: https://docs.mongodb.org/manual/reference/limits/#Restrictions-on-Field-Names
The probable reason you can sometimes successfully create the doc using Robomongo is because Robomongo is transforming your query into a string and properly escaping the special characters as it sends it to MongoDB.
This also explains why your attempt to update them never works. You tried to create a document, but instead created something that is a string object, so your update conditions are probably not retrieving any docs.
I see two problems with your approach.
In following query
db.queries.insert({
"name" : "query1",
"query": { the thing printed above starting with "$or"... }
})
a valid JSON expects key, value pair. here in "query" you are storing an object without a key. You have two options. either store query as text or create another key inside curly braces.
Second problem is, you are storing query values without wrapping in quotes. All string values must be wrapped in quotes.
so your final document should appear as
db.queries.insert({
"name" : "query1",
"query": 'the thing printed above starting with "$or"... '
})
Now try, it should work.
Obviously my attempt to store a query in mongo the way I did was foolish as became clear from the answers from both #bigdatakid and #lix. So what I finally did was this: I altered the naming of the fields to comply to the mongo requirements.
E.g. instead of $or I used _$or etc. and instead of using a . inside the name I used a #. Both of which I am replacing in my Java code.
This way I can still easily try and test the queries outside of my program. In my Java program I just change the names and use the query. Using just 2 lines of code. It simply works now. Thanks guys for the suggestions you made.
String documentAsString = query.toJson().replaceAll("_\\$", "\\$").replaceAll("#", ".");
Object q = JSON.parse(documentAsString);
I would like to know how can we access nested array elements in MongoDB
For example, if we have something like :
{
array1 : [
{
array11 : {
name11 : "xyz"
}
},{
array12 : {
name12: "abc",
nums : [1,2,3,4]
}
}
]
}
Now how can I access and update the "name12" field.
And how can I add elements to "nums" field.
A) To find the collection : I am assuming you want to find name12 = "abc".
db.mydata.find({"array1.array12.name12":"abc"}).pretty()
B) To update & Add elements to the nums array use the positional operator :
https://docs.mongodb.com/manual/reference/operator/update/positional/
db.mydata.update({"array1.array12.name12":"abc"},
{$set:{"array1.$.name12":"abc"} ,
$push:{"array1.$.nums":5}
})
On a side note, you should consider redefining your schema so that the arrays have similar structures. It will help you to update in the long run..
you can access it like any traditional js array, in this case, youre accessing objects within arrays so take care of the syntax.
I am new to node (v0.10) stack.
I am trying to achieve the following:
I have (hopefully) multilingual articles in the latest MongoDB such as:
_id
...more fields...
text: [
{lang: 'en', title: 'some title', body: 'body', slug: 'slug'},
....
]
Everytime I display an article in specific language I query as follows:
var query = Model.findOne({'text.slug': slug});
query.exec(function(err, doc){
async.each(doc.text, function(item, callback){
if (item.lang == articleLang) {
//populate the article to display
}
});
res.render('view', {post:articleToDisplay});
});
Slug is unique for each language!
The problem I have is that mongo will return the whole doc with all subdocs and not just the subdoc I searched for. Now I have to choose to iterate over all subdocs and display the appropriate one on client side or use async.each on the server to get the subdoc I need and only send to the views that one. I am doing it with async on the server. Is that OK? Also async iterates asynchronously but node still waits for the whole loop to finish and then renders the view. Am I missing anything thinking that the user is actually blocked until the async.each finishes? I am still trying to wrap my head around this asynchronous execution. Is there a way I can possibly improve how I manage this code? It seems to be quite standard procedure with subdocs!
Thanks in advance for all your help.
To achieve what you want, you need to make use of the aggregation pipeline. Using a simple findOne() would not be of help,
since you would then have to redact sub documents in your code rather than allowing mongodb to do it. find() and findOne() return the whole document when
a document matches the search criteria.
In the aggregation pipleline you could use the $unwind and $match operators to achieve this.
$unwind:
Deconstructs an array field from the input documents to output a
document for each element. Each output document is the input document
with the value of the array field replaced by the element.
First unwind the document based on the text values array.
$match:
Filters the documents to pass only the documents that match the
specified condition(s) to the next pipeline stage.
Then use the $match operator to match the appropriate documents.
db.Model.aggregate([
{$unwind:"$text"},
{$match:{"text.slug":slug,"text.lang":articleLang}}
])
Doing this would return you only one document with its text field containing only one object. such as: (Note that the text field in the output is not an array)
{ "_id" : ... ,.., "text" : { "slug" : "slug", "lang" : "en" ,...} }
I have a collection of documents for the form:
{ name:String, groceries:{ apples:Number, cherries:Number, prunes:Number } }
Now, every query I have to increment with positive and/or negative values for each element in "groceries". It is not important what keys or how many, I just added some examples.
I could do a :
var dataToBeIncremented = stuff;
var $inc = {};
for each( var index in dataToBeIncremented )
{
$inc[ "groceries." + index ] = dataToBeIncremented[ index ];
}
then
db.update( { _id:targetID }, { $inc : query } )
however, I might have thousands of grocery elements and find doing this loop at each update to be ugly and unoptimized.
I would like to know how to void this or why it can't be optimized.
Actually there is no way to avoid it, because there is no such command that can increment all the values inside the subdocument.
So the only way to do it is to do something like you have done:
{
"$inc": {
"groceries.apples" : 1,
"groceries.cherries" : 1,
"groceries.prunes" : 1
}
}
Because you do not know what are the fields exactly, you need to find them beforehand and to create the $inc statement. There is one good thing about these updates: no matter how may elements do you have, you will still need only 2 queries (find what to update and to actually perform update).
I was also thinking how to achieve a better results with a different schema, but apparently you have to cope with what you have.