I need to find all the documents in mongodb that have keywords that start with number 1-9, then add a '+' in front of the keyword, I can easily find the documents but cannot figure out how to update them.
I tried this one, but it doesn't work
db.placements.update({program_id:{$in:[113,107]},
keyword:{$regex:'^[0-9]', $options:'i'}},
{keyword:"+"+$keyword})
It cannot recognize $keyword, I also tried '.keyword', 'keyword', none of them works. Is there any way to reference the document itself like Java does, using 'this', so I can do something like
this.keyword: "+" + this.keyword
You'll have to use the $set operator in the update query to update a specific field. Also, you cannot concatenate string within an update query. One way to do this would be using cursor forEach() in the shell:
db.placements.find({program_id:{$in:[113,107]}, keyword:{$regex:'^[0-9]', $options:'i'}})
.forEach(function(doc){
db.placements.updateOne({_id:doc._id}, {$set:{"keyword":"+" + doc.keyword}})
})
No, you cannot reference a value on the document itself when querying like you can with SQL.
I would suggest querying the document, updating it on your web/app server and then updating the value back to mongodb.
You will also find that your update command above will wipe your entire document leaving only the keyword field. You should use the $set modifier to update a field or set of fields.
db.placements.update(
{
program_id:{$in:[113,107]},
keyword:{$regex:'^[0-9]', $options:'i'}
},
{ $set: {keyword: new_value}})
Related
I am new in MongoDB. I have a collection in MongoDB. I would like to shift a column in collection of MongoDB. I would like to place image as last column and email as before the last column. How can I do that ?
I agree with others who mentioned that the order of keys in a document should not matter.
But if you still want to learn more about it, it is mentioned in the docs that:
MongoDB preserves the order of the document fields following write
operations...
Considering that, you can actually alter the order of fields by removing and re-inserting them (using $unset and $set) or by using the $rename operator which does exactly that. But you will need to do a couple of operations: First rename the image field to something else, than re-rename it back to image like so:
db.test.updateMany({}, {$rename: {image: 'image_'}})
db.test.updateMany({}, {$rename: {image_: 'image'}})
Since this will actually re-insert the image field, it will cause that field to be last in the document.
Apologies if this is a re-post, but I wasn't able to quite get the query I want from the mongodb documentation examples.
Here's my issue. I am unable execute in a single query to either update an array_field of an existing document or add a new document and initialize the array_field with an initial value.
I can use findOne() with some conditional logic, and probably solve this, but I would think mongodb has an implementation of this use case
Here's the code so far:
#data_json = JSON document to be added to collection
collection.update_one({"json_id":data_json["json_id"], "_dashbd_id_":dashboard_id},{{"$addToSet": {"array_field":keyword}},{"$setOnInsert":data_json}}, upsert=True)
I'm querying by the json_id, and _dashbd_id_ from my collection. If it exists, then I intend to add the "keyword" to the array_field. If it doesn't exist, create a new document as data_json which include array_field = [keyword]
Any hints and suggestions are appreciated!
If I understood you correctly you want to update values in Database only if they do not exist as well as create new documents with arrays in them. Okay there is a way in mongodb which I will mention in this reply. I think you should know few commands first that will help you achieve similar result (again there is a simple way just read on)
Let me start with the first part:
to update an element in an array you use dot notation to the index example:
db.collection_name.update({"_id": id}, {'$set': {"array_name.indexNumber": value}})
say we have the following document in collection name cars
db.cars.findOne():
{
_id: 1
name: EvolutionX
brand: Mitsubish
year: 2012
mods: [ turbo, headlights ]
}
Say in the above example we want to update headlights with rearlights we do the following (using mongoshell you can drop quotes in key names, Not when using the array index though):
db.cars.update({id:1}, {$set:{"mods.1":"rearlights"}})
1 is the index to headlights.
Note and be careful here that if you did not use index inside of an array like
db.cars.update({id:1}, {$set:{"mods":"rearlights"}})
this will overwrite the existing document _id:1 and it will lose all other attributes or fields inside the document so it will result in the follow:
db.cars.findOne():
{
_id: 1
mods: [ rearlights ]
}
Now, say we want to add an element tires to mods array you can use $push as:
db.collection_name.update({"_id": id}, {'$push': {"array_name": value}})
so it will be
db.cars.update({"_id":1}, {"$push":{"mods":"tires"}})
now say instead of updating mods array you want to remove "headlights". In this case you use $pop
db.cars.update({"_id":1}, {"$pop":{"mods":"headlights"}})
Now with that in mind. The easy way: in mongodb to add to array only if element does not exist you can use $addToSet. I love this operator because it will only add to array if the element does not exist. Here is how to use it:
db.cars.update({"_id":1}, {"$addToSet":{"mods":"headlights"}})
Now if headlights is in the array it will not be added, else it will be added to the end of array.
Okay that is the first part of the question. The second part which is initializing a document with an array. Okay there are two thoughts here: the first is you do not have to. using the addToSet you can create the array if it does not exist as (assuming _id 2 exist but without mods array):
db.cars.update({"_id":2}, {"$addToSet":{"mods":"bonnet"}})
This will create the array if document _id:2 exist. Assuming _id:3 does not exist you will have plug in a third attribute called upsert
db.cars.update({"_id":3}, {"$addToSet":{"mods":"headlights"}}, {upsert:true})
this will create a third document with array mods with headlights inside of it and _id:3. Note though no other attributes will be added only the _id and mods array
the second thought is when you insert a new document you insert it with empty mods array as mod:[]
I hope that helps
suppose your data_json ,dashboard_id and keyword contain following detail.
dashboard_id = ObjectId("5423200e6694ce357ad2a1ac")
keyword = "testingKeyword"
data_json =
{
"json_id":ObjectId("5423200e6694ce357ad2a1ac"),
"item":"EFG222",
"reorder":false,
}
if you execute below query
db.collection_name.update({"json_id":data_json["json_id"], "_dashbd_id_":dashboard_id},{{"$addToSet": {"array_field":keyword}},{ upsert=True})
than it will push keyword to array_field if document exist or it will insert new document with following detail as below.
{
"_id":ObjectId("5sdvsdv6sdv694ce357ad2a1ac"),
"json_id":ObjectId("5423200e6694ce357ad2a1ac"),
"dashboard_id": ObjectId("sddfb6694ce357ad2a1ac")
"item":"EFG222",
"reorder":false,
"array_field":
[
"testingKeyword"
]
}
I have to add new value (or edit actual) company. I tried this code in console:
db.users.update({email: /debute/},{company: "test"})
But now, in database I have only _id and company. Why other values removed? Or how can I prevent of removing other values in future?
By default, the update function replaces the entire document with the document you pass. But you can also use it to only replace individual fields and leave the others alone by using the $set operator.
db.users.update({email: /debute/},{ $set: { company: "test"} } );
You might also want to specify a third argument { multi: true } to the update. Otherwise it will only update the first document it finds which matches the condition.
You need to use an update operator on order to update an existing document, your code replaces the document with the new document. Here is how to do an update:
db.users.update({email: /debute/},{$set: {company: "test"}})
How do I use wild character in MongoDB while use Update
I want to do like below in mongo db is it possible to write it.
update emp set sal=sal*2 where ename like '%Pr%';
emp is the collection name
columns: ename, eno, sal
You can use a regexp for your wildcard search, but you have to do the update client-side, because mongoDB is not able to access the content of another field (or the field's content itself) while updating:
db.emp.find( { ename: /Pr/ } ).forEach( function (x) {
x.sal = x.sal * 2;
db.emp.save( x );
});
In MongoDB 2.6 you will be able to do that update enirely server-side using the new $mul operator. As of the time of this posting 2.6 is still in pre-relase; you can check the MongoDB download page for availability. Check the release notes for a complete list of changes and new features.
Also note that you should use an anchored regexp query, that is one that begins with ^, if you know that the string you are searching for is at the beginning of the field. Anchored regexp queries are more efficient because they can use an index and avoid a table scan.
Here is the query with these two changes:
db.emp.update({ename: /^Pr/}, {$mul: {sal: 2}}, {multi: true})
I am trying to use upsert in MongoDB to update a single field in a document if found OR insert a whole new document with lots of fields. The problem is that it appears to me that MongoDB either replaces every field or inserts a subset of fields in its upsert operation, i.e. it can not insert more fields than it actually wants to update.
What I want to do is the following:
I query for a single unique value
If a document already exists, only a timestamp value (lets call it 'lastseen') is updated to a new value
If a document does not exists, I will add it with a long list of different key/value pairs that should remain static for the remainder of its lifespan.
Lets illustrate:
This example would from my understanding update the 'lastseen' date if 'name' is found, but if 'name' is not found it would only insert 'name' + 'lastseen'.
db.somecollection.update({name: "some name"},{ $set: {"lastseen": "2012-12-28"}}, {upsert:true})
If I added more fields (key/value pairs) to the second argument and drop the $set, then every field would be replaced on update, but would have the desired effect on insert. Is there anything like $insert or similar to perform operations only when inserting?
So it seems to me that I can only get one of the following:
The correct update behavior, but would insert a document with only a subset of the desired fields if document does not exist
The correct insert behavior, but would then overwrite all existing fields if document already exists
Are my understanding correct? If so, is this possible to solve with a single operation?
MongoDB 2.4 has $setOnInsert
db.somecollection.update(
{name: "some name"},
{
$set: {
"lastseen": "2012-12-28"
},
$setOnInsert: {
"firstseen": <TIMESTAMP> # set on insert, not on update
}
},
{upsert:true}
)
There is a feature request for this ( https://jira.mongodb.org/browse/SERVER-340 ) which is resolved in 2.3. Odd releases are actually dev releases so this will be in the 2.4 stable.
So there is no real way in the current stable versions to do this yet. I am afraid the only method is to actually do 3 conditional queries atm: 1 to check the row, then a if to either insert or update.
I suppose if you had real problems with lock here you could do this function with sole JS but that's evil however it would lock this update to a single thread.