I wish to be able to access the same data from multiple keys in a JSON file.
"TypeA","TypeB","TypeC": "These types are not supported",
"TypeR": "Vroom vroom!"
The actual problem is more complex, the data is a serialized object. But this is the current crux of the issue.
You could have something like:
{
"TypeA" : "COMMON_TYPE_VALUE",
"TypeB" : "COMMON_TYPE_VALUE",
"TypeC" : "COMMON_TYPE_VALUE",
"COMMON_TYPE_VALUE" : "here is the common value"
}
You'd have to know all the common keys up front of course...
Sounds like you might need to make it relational.
"Types": [
"These types are not supported",
"Vroom vroom!"
],
...
"TypeA": 0,
"TypeB": 0,
"TypeC": 0,
"TypeR": 1
Maybe not the best structure but it highlights the idea.
Related
Looking to filter this json body for specific key/values for when a certain condition is met.
For this body - I'd like to retrieve ONLY the recipient ID and Tracking Number for when the requester ID is 67890.
{
"metadata": "someinformation",
"access": "XXXX",
"recipient": {
"id": "12345"
},
"requester": {
"id": "67890"
},
"trackingNumber": "ABCDEF"
}
This would be using Goessner https://goessner.net/articles/JsonPath/index.html
I am able to get the attributes mostly using: $..[trackingNumber,requester,recipient] but it removes the key of "trackingNumber" and only does a value.
Also the filter I want to use alongside that would be: [?($.requester.id=="67890")]
The expectation is other requester ID's will be in other json bodies - but we only want to filter for the ones that have this present and select the specific attributes.
You going to need to do this in two queries, one for each value that you want back.
For recipient:
$[?(#.requester.id == '67890')].recipient.id
For tracking number:
$[?(#.requester.id == '67890')].trackingNumber
I don't think Goessner's implementation supports returning multiple values like you want. It's not something that will be supported in the upcoming spec, either.
Let's say my JSON looks like this (example provided here) -
{
"year" : 2013,
"title" : "Turn It Down, Or Else!",
"info" : {
"directors" : [
"Alice Smith",
"Bob Jones"
],
"release_date" : "2013-01-18T00:00:00Z",
"rating" : 6.2,
"genres" : [
"Comedy",
"Drama"
],
"image_url" : "http://ia.media-imdb.com/images/N/O9ERWAU7FS797AJ7LU8HN09AMUP908RLlo5JF90EWR7LJKQ7##._V1_SX400_.jpg",
"plot" : "A rock band plays their music at high volumes, annoying the neighbors.",
"rank" : 11,
"running_time_secs" : 5215,
"actors" : [
"David Matthewman",
"Ann Thomas",
"Jonathan G. Neff"
]
}
}
I would like to query all movies where genres contains Drama.
I went through all of the examples but it seems that I can query only on hash key and sort key. I can't have JSON document as key itself as that is not supported.
You cannot. DynamoDB requires that all attributes you are filtering for have an index.
As you want to query independently of your main index, you are limited to Global Secondary Indexes.
The documentation lists on what kind of attributes indexes are supported:
The index key attributes can consist of any top-level String, Number, or Binary attributes from the base table; other scalar types, document types, and set types are not allowed.
Your type would be an array of Strings. So this query operation isn't supported by DynamoDB at this time.
You might want to consider other NoSQL document based databases which are more flexible like MongoDB Atlas, if you need this kind of querying functionality.
String filterExpression = "coloumnname.info.genres= :param";
Map valueMap = new HashMap();
valueMap.put(":param", "Drama");
ItemCollection scanResult = table
.scan(new ScanSpec().
withFilterExpression(filterExpression).
withValueMap(valueMap));
One example that I took from AWS Developer Forums is as follows.
We got some hints for you from our team. Filter/condition expressions for maps have to have key names at each level of the map specified separately in the expression attributeNames map.
Your expression should look like this:
{
"TableName": "genericPodcast",
"FilterExpression": "#keyone.#keytwo.#keythree = :keyone",
"ExpressionAttributeNames": {
"#keyone": "attributes",
"#keytwo": "playbackInfo",
"#keythree": "episodeGuid"
},
"ExpressionAttributeValues": {
":keyone": {
"S": "podlove-2018-05-02t19:06:11+00:00-964957ce3b62a02"
}
}
}
I am a newbie to MongoDB. I am experimenting the various ways of extracting fields from a document inside collection.
Here in the below JSON document, I am finding it difficult to get extract it according to my need
{
"_id":1,
"dependencies":{
"a":[
"hello",
"hi"
],
"b":[
"Hmmm"
],
"c":[
"Vanilla",
"Strawberry",
"Pista"
],
"d":[
"Carrot",
"Cauliflower",
"Potato",
"Cabbage"
]
},
"productid":"25",
"date":"Thu Jul 30 11:36:49 PDT 2015"
}
I need to display the following output:
c:[
"Vanilla",
"Strawberry",
"Pista"
]
Can anyone please help me in solving it?
MongoDB Aggregation comes into rescue to get the result you are looking for :
$Project--> Passes along the documents with only the specified fields to the next stage in the pipeline. The specified fields can be existing fields from the input documents or newly computed fields.
db.collection.aggregate( [
{ $project :
{ c: "$dependencies.c", _id : 0 }
}
]).pretty();
As per the output you required, we just need to project ( display) the field "dependencies.c" , so we are creating a new field "c" and assigining the value of the "dependencies.c" into it.
Also by defalut "_id" field will be display along with the result, since you dont need it, so we are suppressing of the _id field by assigining "_id" : <0 or false>, so that it will not display the _id field in the output.
The above query will fetch you the result as below :
"c" : [
"Vanilla",
"Strawberry",
"Pista"
]
I need a little help regarding lucene index files, thought, maybe some of you guys can help me out.
I have json like this:
[
{
"Id": 4476,
"UrlName": null,
"PhoneData": [
{
"PhoneType": "O",
"PhoneNumber": "0065898",
},
{
"PhoneType": "F",
"PhoneNumber": "0065898",
}
],
"Contact": [],
"Services": [
{
"ServiceId": 10,
"ServiceGroup": 2
},
{
"ServiceId": 20,
"ServiceGroup": 1
}
],
}
]
Adding first two fields is relatively easy:
// add lucene fields mapped to db fields
doc.Add(new Field("Id", sampleData.Id.Value.ToString(), Field.Store.YES, Field.Index.NOT_ANALYZED));
doc.Add(new Field("UrlName", sampleData.UrlName.Value ?? "null" , Field.Store.YES, Field.Index.ANALYZED));
But how I can add PhoneData and Services to index so it can be connected to unique Id??
For indexing JSON objects I would go this way:
Store the whole value under a payload field, named for example $json. This field would be stored but not indexed.
For each (indexable) property (maybe nested) create an indexable field with its name as a XMLPath-like expression identifying the property, for example PhoneData.PhoneType
If is ok that all nested properties will be indexed then it's simple, just iterate over all of them generating this indexable field.
But if you don't want to index all of them (a more realistic case), how to know which property is indexable is another problem; in this case you could:
Accept from the client the path expressions of the index fields to be created when storing the document, or
Put JSON Schema into play to describe your data (assuming your JSON records have a common schema), and extend it with a custom property that would allow you to tag which properties are indexable.
I have created a library doing this (and much more) that maybe can help you.
You can check it at https://github.com/brutusin/flea-db
Ahoy! I'm having a very funny issue with MongoDB and, possibly more in general, with JSON. Basically, I accidentally created some MongoDB documents whose subdocuments contain an empty key, e.g. (I stripped ObjectIDs to make the code look nicer):
{
"_id" : ObjectId("..."),
"stats" :
{
"violations" : 0,
"cost" : 170,
},
"parameters" :
{
"" : "../instances/comp/comp20.ectt",
"repetition" : 29,
"time" : 600000
},
"batch" : ObjectId("..."),
"system" : "Linux 3.5.0-27-generic",
"host" : "host3",
"date_started" : ISODate("2013-05-14T16:46:46.788Z"),
"date_stopped" : ISODate("2013-05-14T16:56:48.483Z"),
"copy" : false
}
Of course the problem is line:
"" : "../instances/comp/comp20.ectt"
since I cannot get back the value of the field. If I query using:
db.experiments.find({"batch": ObjectId("...")}, { "parameters.": 1 })
what I get is the full content of the parameters subdocument. My guess is that . is probably ignored if followed by an empty selector. From the JSON specification (15.12.*) it looks like empty keys are allowed. Do you have any ideas about how to solve that?
Is that a known behavior? Is there a use for that?
Update I tried to $rename the field, but that won't work, for the same reasons. Keys that end with . are not allowed.
Update filed issue on MongoDB issue tracker.
Thanks,
Tommaso
I have this same problem. You can select your sub-documents with something like this:
db.foo.find({"parameters.":{$exists:true}})
The dot at the end of "parameters" tells Mongo to look for an empty key in that sub-document. This works for me with Mongo 2.4.x.
Empty keys are not well supported by Mongo, I don't think they are officially supported, but you can insert data with them. So you shouldn't be using them and should find the place in your system where these keys are inserted and eliminate it.
I just checked the code and this does not currently seem possible for the reasons you mention. Since it is allowed to create documents with zero length field names I would consider this a bug. You can report it here : https://jira.mongodb.org
By the way, ironically you can query on it :
> db.c.save({a:{"":1}})
> db.c.save({a:{"":2}})
> db.c.find({"a.":1})
{ "_id" : ObjectId("519349da6bd8a34a4985520a"), "a" : { "" : 1 } }