I'm trying to query my database for prices greater than/less than a user specified number. In my database, prices are stored like so:
{price: "300.00"}
According to the docs, this should work:
db.products.find({price: {$gt:30.00}}).pretty()
But I get no results returned. I've also tried {price: {$gt:30}}.
What am I missing here?
It it because the prices are stored as a string rather than a number in the DB? Is there a way around this?
If you intend to use $gt with strings, you will have to use regex, which is not great in terms of performance. It is easier to just create a new field which holds the number value of price or change this field type to int/double. A javascript version should also work, like so:
db.products.find("this.price > 30.00")
as js will convert it to number before use. However, indexes won't work on this query.
$gt is an operator that can work on any type:
db.so.drop();
db.so.insert( { name: "Derick" } );
db.so.insert( { name: "Jayz" } );
db.so.find( { name: { $gt: "Fred" } } );
Returns:
{ "_id" : ObjectId("51ffbe6c16473d7b84172d58"), "name" : "Jayz" }
If you want to compare against a number with $gt or $lt, then the value in your document also needs to be a number. Types in MongoDB are strict and do not auto-convert like they f.e. would do in PHP. In order to solve your issue, make sure you store the prices as numbers (floats or ints):
db.so.drop();
db.so.insert( { price: 50.40 } );
db.so.insert( { price: 29.99 } );
db.so.find( { price: { $gt: 30 } } );
Returns:
{ "_id" : ObjectId("51ffbf2016473d7b84172d5b"), "price" : 50.4 }
Starting Mongo 4.0, there is a new $toDouble aggregation operator which converts from various types to double (in this case from a string):
// { price: "300.00" }
// { price: "4.2" }
db.collection.find({ $expr: { $gt: [{ $toDouble: "$price" }, 30] } })
// { price: "300.00" }
If you have newer version of mongodb then you can do this:
$expr: {
$gt: [
{ $convert: { input: '$price', to: 'decimal' } },
{ $convert: { input: '0.0', to: 'decimal' } }
]
}
$expr operator: https://docs.mongodb.com/manual/reference/operator/query/expr/
$convert opetator: https://docs.mongodb.com/manual/reference/operator/aggregation/convert/index.html
Alternatively you can convert the values to Int, as per:
http://www.quora.com/How-can-I-change-a-field-type-from-String-to-Integer-in-mongodb
var convert = function(document){
var intValue = parseInt(document.field, 10);
db.collection.update(
{_id:document._id},
{$set: {field: intValue}}
);
}
db.collection.find({field: {$type:2}},{field:1}).forEach(convert)
Related
I'm using mongoDB version 3.2. and i want to check if a string is exist in an array of string, i want to use the regex so if just a part of the given string is exist in a string in the array, that record should be returned.
here's an example of a record:
{
name: "initiative 1",
portfolioItems: ["Non clinical", "ITS portfolio", "Lean"]
}
the following query does not work:
db.collection.aggregate([
{
$match:
{ 'portfolioItems' : { $in: [/term/] } }
}
])
is there anyway to achieve that ?
Try this one.
db.collection.aggregate([
{
$match:
{"portfolioItems":{'$regex':"^it", '$options': 'i'}}
}
])
The symbol ^ used to start from the first of string. If u don't need it. You can remove it.
Your query become
{
$match:
{"portfolioItems":{'$regex':"^"+term, '$options': 'i'}}
}
You have to match the pattern in each element of array.
Try this :
{ 'portfolioItems' : { $regex: [/term/] } }
I'm in this scenario right now:
I have a collection X:
{
_id:ObjectId('56edbb4d5f084a51131dd4c6'),
userRef:ObjectId('56edbb4d5f084a51131dd4c6'),
serialNumber:'A123123',
...
}
I need to aggregate all documents, grouping them by the userRef + serialNumber, so I'm trying to use concat like this:
$group: {
_id: {
'$concat': ['$userRef','-','$serialNumber']
},
...
So basically in my aggregation in MongoDB, I need to group documents by the concatenation of a ObjectId and a string. However, It seems that $concat only accepts strings as parameters:
uncaught exception: aggregate failed: {
"errmsg" : "exception: $concat only supports strings, not OID",
"code" : 16702,
"ok" : 0
}
Is there a way to convert an ObjectId to a String within an aggregation expression?
EDIT:
This question is related, but I the solution doesn't fit my problem. (Specially because I can't use ObjectId.toString() during the aggregation)
Indeed I couldn't find any ObjectId().toString() operation in Mongo's documentation, but I wonder if there's any tricky thing that can be done in this case.
Now you can try with $toString aggregation which simply
converts ObjectId to string
db.collection.aggregate([
{ "$addFields": {
"userRef": { "$toString": "$userRef" }
}},
{ "$group": {
"_id": { "$concat": ["$userRef", "-", "$serialNumber"] }
}}
])
You can check the output here
I couldn't find a way to do what I wanted, so instead, I created a MapReduce function that, in the end, generated the keys the way I wanted to (concatenating other keys).
At the end, it looked something like this:
db.collection('myCollection').mapReduce(
function() {
emit(
this.userRef.str + '-' + this.serialNumber , {
count: 1,
whateverValue1:this.value1,
whateverValue2:this.value2,
...
}
)
},
function(key, values) {
var reduce = {}
.... my reduce function....
return reduce
}, {
query: {
...filters_here....
},
out: 'name_of_output_collection'
}
);
You can simply use $toString to apply $concat in aggregation on ObjectIDs in the following way -
$group: {
'_id': {
'$concat': [
{ '$toString' : '$userRef' },
'-',
{ '$toString' : '$serialNumber'}
]
},
}
I think you may try to resolve it by using an Array which contains both fields:
{$project:{newkey:['$userRef','$serialNumber']},{$match:{newkey:{$in:filterArray}}}}
this may match the data with both fields to the filter. Please notice that the data in the newkey array should have the same data type with the filterArray elements.
You can use $substr https://docs.mongodb.com/manual/reference/operator/aggregation/substr/#exp._S_substr to cast any object to string before $concat.
This is a sample of code that's working for me.
group_id_i['_id'] = {
'$concat' => [
{ '$substr' => [ {'$year' => '$t'}, 0, -1] }, '-',
{ '$substr' => [ {'$month' => '$t'}, 0, -1] }, '-',
{ '$substr' => [ {'$dayOfMonth' => '$t'}, 0, -1] }
]
}
Where t is DateTime field, this aggregation returns data like so.
{
"_id" => "28-9-2016",
"i" => 2
}
What I'm trying to do is pretty straightforward, but I can't find out how to give one field the value of another.
I simply want to update one field with the character count of another.
db.collection.update({$exists:true},{$set : {field1 : field2.length}})
I've tried giving it dot notation
db.collection.update({$exits:true},{$set : {field1: "this.field2.length"}})
As well as using javascript syntax
db.collection.update({$exits:true},
{$set : {field1: {$where : "this.field2.length"}})
But just copied the string and got a "notOkforstorage" respectively. Any help?
Update:
I only get the "notOkforStorage" when I query by ID:
db.collection.update({_id:ObjectID("38289842bbb")},
{$set : {field1: {$where :"this.field2.length"}}})
Try the following code:
db.collection.find(your_querry).forEach(function(doc) {
doc.field1 = doc.field2.length;
db.collection.save(doc);
});
You can use your_querry to select only part of the original collection do perform an update. If you want to process an entire collection, use your_querry = {}.
If you want all operations to be atomic, use update instead of save:
db.collection.find( your_querry, { field2: 1 } ).forEach(function(doc) {
db.collection.update({ _id: doc._id },{ $set: { field1: doc.field2.length } } );
});
Starting Mongo 4.2, db.collection.update() can accept an aggregation pipeline, finally allowing the update/creation of a field based on another field:
// { "_id" : ObjectId("5e84c..."), "field1" : 12, "field2" : "world" }
db.collection.update(
{ "_id" : ObjectId("5e84c...") },
[{ $set: { field1: { $strLenCP: "$field2" } } }]
)
// { "_id" : ObjectId("5e84c..."), "field1" : 5, "field2" : "world" }
The first part {} is the match query, filtering which documents to update.
The second part [{ $set: { field1: { $strLenCP: "$field2" } } }] is the update aggregation pipeline (note the squared brackets signifying the use of an aggregation pipeline). $set is a new aggregation operator and an alias for $addFields. Any aggregation operator can be used within the $set stage; in our case $strLenCP which provides the length of field2.
As far I know the easiest way is the read and write aproach:
//At first, get/prepare your new value:
var d= db.yourColl.fetchOne({....});
d.field1== d.field2.length;
// then update with your new value
db.yourColl.save(d);
Your are using exists in the wrong way.
Syntax: { field: { $exists: <boolean> } }
You use of $where is also incorrect
Use the $where operator to pass either a string containing a JavaScript expression or a full JavaScript function to the query system
db.myCollection.find( { $where: "this.credits == this.debits" } );
db.myCollection.find( { $where: "obj.credits == obj.debits" } );
db.myCollection.find( { $where: function() { return (this.credits == this.debits) } } );
db.myCollection.find( { $where: function() { return obj.credits == obj.debits; } } );
I think you should use Map-Reduce for what you are trying to do.
I have a Collection named as Orders in my Mongo DB .
Is it possible to do a search on mongo DB based on two fileds .
For example i want to search the collection based on symbol and hi
db.Orders.find({"symbol" : "AADI"})
Please let me know how can i include the other parameter hi also in the search ??
Thanks
Just have two conditions separated by commas:
e.g.
db.users.find(
{ status: "A",
age: 50 }
)
http://docs.mongodb.org/manual/reference/sql-comparison/
Mongodb provides an implicit AND , so when you do
db.inventory.find( { price: 1.99, qty: { $lt: 20 } , sale: true } )
it is same as
db.inventory.find({ $and: [ { price: 1.99 }, { qty: { $lt: 20 } }, { sale: true } ] } )
For other operators you can have a look at the reference
mixing $or with logical AND
db.inventory.find( { price:1.99, $or: [ { qty: { $lt: 20 } }, { sale: true } ] } )
This query will select all documents in the inventory collection where:
the price field value equals 1.99 and
either the qty field value is less than 20 or the sale field value is true.
Other operators
You can refer to the reference for examples to other operators.
Also, once you use:
db.users.find(
{ status: "A",
age: 50 }).pretty()
Using pretty() method at the end of the statement, you make sure that the info comes with a \n per key : value
I am trying to change the type of a field from within the mongo shell.
I am doing this...
db.meta.update(
{'fields.properties.default': { $type : 1 }},
{'fields.properties.default': { $type : 2 }}
)
But it's not working!
The only way to change the $type of the data is to perform an update on the data where the data has the correct type.
In this case, it looks like you're trying to change the $type from 1 (double) to 2 (string).
So simply load the document from the DB, perform the cast (new String(x)) and then save the document again.
If you need to do this programmatically and entirely from the shell, you can use the find(...).forEach(function(x) {}) syntax.
In response to the second comment below. Change the field bad from a number to a string in collection foo.
db.foo.find( { 'bad' : { $type : 1 } } ).forEach( function (x) {
x.bad = new String(x.bad); // convert field to string
db.foo.save(x);
});
Convert String field to Integer:
db.db-name.find({field-name: {$exists: true}}).forEach(function(obj) {
obj.field-name = new NumberInt(obj.field-name);
db.db-name.save(obj);
});
Convert Integer field to String:
db.db-name.find({field-name: {$exists: true}}).forEach(function(obj) {
obj.field-name = "" + obj.field-name;
db.db-name.save(obj);
});
Starting Mongo 4.2, db.collection.update() can accept an aggregation pipeline, finally allowing the update of a field based on its own value:
// { a: "45", b: "x" }
// { a: 53, b: "y" }
db.collection.updateMany(
{ a : { $type: 1 } },
[{ $set: { a: { $toString: "$a" } } }]
)
// { a: "45", b: "x" }
// { a: "53", b: "y" }
The first part { a : { $type: 1 } } is the match query:
It filters which documents to update.
In this case, since we want to convert "a" to string when its value is a double, this matches elements for which "a" is of type 1 (double)).
This table provides the code representing the different possible types.
The second part [{ $set: { a: { $toString: "$a" } } }] is the update aggregation pipeline:
Note the squared brackets signifying that this update query uses an aggregation pipeline.
$set is a new aggregation operator (Mongo 4.2) which in this case modifies a field.
This can be simply read as "$set" the value of "a" to "$a" converted "$toString".
What's really new here, is being able in Mongo 4.2 to reference the document itself when updating it: the new value for "a" is based on the existing value of "$a".
Also note "$toString" which is a new aggregation operator introduced in Mongo 4.0.
In case your cast isn't from double to string, you have the choice between different conversion operators introduced in Mongo 4.0 such as $toBool, $toInt, ...
And if there isn't a dedicated converter for your targeted type, you can replace { $toString: "$a" } with a $convert operation: { $convert: { input: "$a", to: 2 } } where the value for to can be found in this table:
db.collection.updateMany(
{ a : { $type: 1 } },
[{ $set: { a: { $convert: { input: "$a", to: 2 } } } }]
)
For string to int conversion.
db.my_collection.find().forEach( function(obj) {
obj.my_value= new NumberInt(obj.my_value);
db.my_collection.save(obj);
});
For string to double conversion.
obj.my_value= parseInt(obj.my_value, 10);
For float:
obj.my_value= parseFloat(obj.my_value);
db.coll.find().forEach(function(data) {
db.coll.update({_id:data._id},{$set:{myfield:parseInt(data.myfield)}});
})
all answers so far use some version of forEach, iterating over all collection elements client-side.
However, you could use MongoDB's server-side processing by using aggregate pipeline and $out stage as :
the $out stage atomically replaces the existing collection with the
new results collection.
example:
db.documents.aggregate([
{
$project: {
_id: 1,
numberField: { $substr: ['$numberField', 0, -1] },
otherField: 1,
differentField: 1,
anotherfield: 1,
needolistAllFieldsHere: 1
},
},
{
$out: 'documents',
},
]);
To convert a field of string type to date field, you would need to iterate the cursor returned by the find() method using the forEach() method, within the loop convert the field to a Date object and then update the field using the $set operator.
Take advantage of using the Bulk API for bulk updates which offer better performance as you will be sending the operations to the server in batches of say 1000 which gives you a better performance as you are not sending every request to the server, just once in every 1000 requests.
The following demonstrates this approach, the first example uses the Bulk API available in MongoDB versions >= 2.6 and < 3.2. It updates all
the documents in the collection by changing all the created_at fields to date fields:
var bulk = db.collection.initializeUnorderedBulkOp(),
counter = 0;
db.collection.find({"created_at": {"$exists": true, "$type": 2 }}).forEach(function (doc) {
var newDate = new Date(doc.created_at);
bulk.find({ "_id": doc._id }).updateOne({
"$set": { "created_at": newDate}
});
counter++;
if (counter % 1000 == 0) {
bulk.execute(); // Execute per 1000 operations and re-initialize every 1000 update statements
bulk = db.collection.initializeUnorderedBulkOp();
}
})
// Clean up remaining operations in queue
if (counter % 1000 != 0) { bulk.execute(); }
The next example applies to the new MongoDB version 3.2 which has since deprecated the Bulk API and provided a newer set of apis using bulkWrite():
var bulkOps = [];
db.collection.find({"created_at": {"$exists": true, "$type": 2 }}).forEach(function (doc) {
var newDate = new Date(doc.created_at);
bulkOps.push(
{
"updateOne": {
"filter": { "_id": doc._id } ,
"update": { "$set": { "created_at": newDate } }
}
}
);
})
db.collection.bulkWrite(bulkOps, { "ordered": true });
To convert int32 to string in mongo without creating an array just add "" to your number :-)
db.foo.find( { 'mynum' : { $type : 16 } } ).forEach( function (x) {
x.mynum = x.mynum + ""; // convert int32 to string
db.foo.save(x);
});
What really helped me to change the type of the object in MondoDB was just this simple line, perhaps mentioned before here...:
db.Users.find({age: {$exists: true}}).forEach(function(obj) {
obj.age = new NumberInt(obj.age);
db.Users.save(obj);
});
Users are my collection and age is the object which had a string instead of an integer (int32).
You can easily convert the string data type to numerical data type.
Don't forget to change collectionName & FieldName.
for ex : CollectionNmae : Users & FieldName : Contactno.
Try this query..
db.collectionName.find().forEach( function (x) {
x.FieldName = parseInt(x.FieldName);
db.collectionName.save(x);
});
I need to change datatype of multiple fields in the collection, so I used the following to make multiple data type changes in the collection of documents. Answer to an old question but may be helpful for others.
db.mycoll.find().forEach(function(obj) {
if (obj.hasOwnProperty('phone')) {
obj.phone = "" + obj.phone; // int or longint to string
}
if (obj.hasOwnProperty('field-name')) {
obj.field-name = new NumberInt(obj.field-name); //string to integer
}
if (obj.hasOwnProperty('cdate')) {
obj.cdate = new ISODate(obj.cdate); //string to Date
}
db.mycoll.save(obj);
});
demo change type of field mid from string to mongo objectId using mongoose
Post.find({}, {mid: 1,_id:1}).exec(function (err, doc) {
doc.map((item, key) => {
Post.findByIdAndUpdate({_id:item._id},{$set:{mid: mongoose.Types.ObjectId(item.mid)}}).exec((err,res)=>{
if(err) throw err;
reply(res);
});
});
});
Mongo ObjectId is just another example of such styles as
Number, string, boolean that hope the answer will help someone else.
I use this script in mongodb console for string to float conversions...
db.documents.find({ 'fwtweaeeba' : {$exists : true}}).forEach( function(obj) {
obj.fwtweaeeba = parseFloat( obj.fwtweaeeba );
db.documents.save(obj); } );
db.documents.find({ 'versions.0.content.fwtweaeeba' : {$exists : true}}).forEach( function(obj) {
obj.versions[0].content.fwtweaeeba = parseFloat( obj.versions[0].content.fwtweaeeba );
db.documents.save(obj); } );
db.documents.find({ 'versions.1.content.fwtweaeeba' : {$exists : true}}).forEach( function(obj) {
obj.versions[1].content.fwtweaeeba = parseFloat( obj.versions[1].content.fwtweaeeba );
db.documents.save(obj); } );
db.documents.find({ 'versions.2.content.fwtweaeeba' : {$exists : true}}).forEach( function(obj) {
obj.versions[2].content.fwtweaeeba = parseFloat( obj.versions[2].content.fwtweaeeba );
db.documents.save(obj); } );
And this one in php)))
foreach($db->documents->find(array("type" => "chair")) as $document){
$db->documents->update(
array('_id' => $document[_id]),
array(
'$set' => array(
'versions.0.content.axdducvoxb' => (float)$document['versions'][0]['content']['axdducvoxb'],
'versions.1.content.axdducvoxb' => (float)$document['versions'][1]['content']['axdducvoxb'],
'versions.2.content.axdducvoxb' => (float)$document['versions'][2]['content']['axdducvoxb'],
'axdducvoxb' => (float)$document['axdducvoxb']
)
),
array('$multi' => true)
);
}
The above answers almost worked but had a few challenges-
Problem 1: db.collection.save no longer works in MongoDB 5.x
For this, I used replaceOne().
Problem 2: new String(x.bad) was giving exponential number
I used "" + x.bad as suggested above.
My version:
let count = 0;
db.user
.find({
custID: {$type: 1},
})
.forEach(function (record) {
count++;
const actualValue = record.custID;
record.custID = "" + record.custID;
console.log(`${count}. Updating User(id:${record._id}) from old id [${actualValue}](${typeof actualValue}) to [${record.custID}](${typeof record.custID})`)
db.user.replaceOne({_id: record._id}, record);
});
And for millions of records, here are the output (for future investigation/reference)-