I am trying to filter on a view which emits bookName and bookItem.
emit([doc.basicInfo.bookName,doc.basicInfo.bookItem], 1);
it gives me below result without any query:
{"total_rows”:10,”offset":0,"rows":[
{"id":"d4e5548fb01e6e2c559e702fe7b138ad","key":["correctaccouts","billing"],"value":1},
{"id":"863c46c645b6344719a08231606f2a7d","key":["credeaccount","system"],"value":1},
{"id":"68d39e64c406127960dc735e8167eee3","key":["credeaccount11","system"],"value":1},
{"id":"1ab4d31588d76a42e85b526a316074de","key":["mayankamazon","billing"],"value":1},
{"id":"3204f5db5df91886373f95995ce09a2d","key":["mayankazure","asset"],"value":1},
{"id":"452c040048fb2b779205b3785615d368","key":["mayankmaaa","system"],"value":1},
{"id":"23f01f7bc60c2c8f24f6b741584a69fa","key":["TEST_AWS_Delete212sss12","asset"],"value":1},
{"id":"f0093f474e0d50f046b9fdc9145bdc91","key":["vijeth-myteam111115555555","asset"],"value":1},
{"id":"c3bce8dd1482d841f445fbd617ba1db7","key":["vijeth-myteam11111555sss5555","asset"],"value":1},
{"id":"347479ba91696b73f4a57252cd00a358","key":["vijeth-myteamOnly","asset"],"value":1}
]}
Now I am trying to query on it using complex keys:
satrtkey=[{},"asset"]&endkey=[{},"asset"]
It should return me:
{"total_rows”:5,”offset":0,"rows":[
{"id":"3204f5db5df91886373f95995ce09a2d","key":["mayankazure","asset"],"value":1},
{"id":"23f01f7bc60c2c8f24f6b741584a69fa","key":["TEST_AWS_Delete212sss12","asset"],"value":1},
{"id":"f0093f474e0d50f046b9fdc9145bdc91","key":["vijeth-myteam111115555555","asset"],"value":1},
{"id":"c3bce8dd1482d841f445fbd617ba1db7","key":["vijeth-myteam11111555sss5555","asset"],"value":1},
{"id":"347479ba91696b73f4a57252cd00a358","key":["vijeth-myteamOnly","asset"],"value":1}
]}
But it still gives me all 10 records. I want to filter only records of type "asset".
To use key ranges, you must narrow down your research starting with the left fields to the right fields.
For example, if your key would be: [doc.basicInfo.bookItem,doc.basicInfo.bookName]
You could search with start_key=["asset",null]&end_key=["asset",{}]
Also, your current query is equivalent to key=[{},"asset"]. Instead, you should have tried: start_key=[null,"asset"]&end_key=[{},"asset"] but it should not work.
Example
View:
function (doc) {
emit([doc.basicInfo.bookItem,doc.basicInfo.bookName], 1);
}
Query:
http://localhost:5984/<db>/_design/<design_name>/_view/<view_name>?include_docs=true&inclusive_end=true&start_key=%5B%22asset%22%2Cnull%5D&end_key=%5B%22asset%22%2C%7B%7D%5D
Related
I have a view which outputs the following JSON:
{"total_rows":26,"offset":0,"rows":[
{"id":"SIP-13","key":[1506146852518,"SIP-13"],"value":{"clientId":"CLIENT-2","orderCount":2}},
{"id":"SIP-12","key":[1506147024308,"SIP-12"],"value":{"orderCount":1}},
{"id":"SIP-14","key":[1506159901457,"SIP-14"],"value":{"orderCount":1}},
{"id":"SIP-15","key":[1506161053712,"SIP-15"],"value":{"clientId":"CLIENT-2","orderCount":2}},
{"id":"SIP-16","key":[1506448298050,"SIP-16"],"value":{"clientId":"CLIENT-3","orderCount":1}}
]}
...and I want to get the row with id: "SIP-15" here. How can I do that?
You have to use complex keys. The first field indexed can be anything and the second must be SIP-15.
Query :
?startkey=[null,"SIP-15"]&endkey=[{},"SIP-15"]
I am brand new to noSQL, couchDB, and mapreduce and need some help.
I have the same question discussed here {How to use reduce in Fauxton} but do not understand the answer:(.
I have a working map function:
function (foo) {
if(foo.type == "blog post");
emit(foo)
}
which returns 11 individual documents. I want to modify this to return foo.type along with a count of 1.
I have tried:
function (doc) {
if(doc.type == "blog post");
return count(doc)
}
and "_count" from the Reduce panel, but clearly am doing something wrong as the View does not return anything.
Thanks in advance for any assistance or guidance!
In Fauxton, the Reduce step is kind of awkward and unintuitive to find.
Select _count in the "Reduce (optional)" popup below where you type
in your Map.
Select "Save Document and then Build Index". That will display your
map results.
Find the "Options" button at the top next to a gears icon. If you see a
green band instead, close the green band with the X.
Select Options, then the "Reduce" check-circle. Select Run Query.
Map
So when you build a map function, you are literally creating a dictionnary or map which are key:value data structures.
Your map function should emit keys that you will query. You can also emit a value but if you intend to simply get the associated document, you don't have to emit any values. Why? Because there is a query parameter that can be used to return the document associated (?include_docs=true).
Reduce
Then, you can have reduce function which will be called for every result with the same keys. Every result with the same key will be processed through your reduce function to reduce the value.
Corrected example
So in your case, you want to map document the document per type I suppose.
You could create a function that emit documents that have the type property.
function(doc){
if(doc.type)
emit(doc.type);
}
If you query this view, you will see that the keys of each rows will be the type of the document. If you choose the _count reduce function, you should have the number of document per types.
When querying the view, you have to specify : group=true&reduce=true
Also, you can get all the document of type blog postby querying with those parameters : ?key="blog post"
I am wondering if i could filter data in Couchdb similar with IN in MySQL. For example the map function is :
function(doc) {
emit(doc.idWord, [doc.idTwitterData, doc.tf*doc.idf]);
}
I want to select only documents that have idWord with values 1 or 5 for example. I tried to set startkey=1 and endkey=5 but it is not working.
It's very simple. All you need to query is ?keys=[1,5]. This will fetch all the records with the idWord equal to 1 or 5. You might want to encode the [ ]
As an addition: you use the parameters startkey and endkey if you are doing a ranged query. Here is a good explanation how a ranged query works.
I want to be able query the couchdb between dates, I know that this can be done with startkey and endkey (it works fine), but is it possible to do query for example like this:
SELECT *
FROM TABLENAME
WHERE
DateTime >= '2011-04-12T00:00:00.000' AND
DateTime <= '2012-05-25T03:53:04.000'
AND
Status = 'Completed'
AND
Job_category = 'Installation'
Generally-speaking, establishing indexes on multiple fields grows in complexity as the number of fields increases.
My main question is: do Status and Job_category need to be queried dynamically too? If not, your view is simple:
function (doc) {
if (doc.Status === 'Completed' && doc.Job_category === 'Installation') {
emit(doc.DateTime); // this line may change depending on how you break up and emit the datetimes
}
}
Views are fairly cheap, (depending on the size of your database) so don't be afraid to establish several that cover different cases. I would expect something like Status to have predefined list of available options, as oppposed to Job_category which seems like it could be more related to user input.
If you need those fields to be dynamic, you can just add them to the index as well:
function (doc) {
emit([ doc.Status, doc.Job_category, doc.DateTime ]);
}
Then you can use an array as your start_key. For example:
start_key=["Completed", "Installation", ...]
tl;dr: use "static" views where you have a predetermined list of values for a given field. while possible to query "dynamic" views with multiple fields, the complexity grows very quickly.
I have a Couchdb database with documents of the form: { Name, Timestamp, Value }
I have a view that shows a summary grouped by name with the sum of the values. This is straight forward reduce function.
Now I want to filter the view to only take into account documents where the timestamp occured in a given range.
AFAIK this means I have to include the timestamp in the emitted key of the map function, eg. emit([doc.Timestamp, doc.Name], doc)
But as soon as I do that the reduce function no longer sees the rows grouped together to calculate the sum. If I put the name first I can group at level 1 only, but how to I filter at level 2?
Is there a way to do this?
I don't think this is possible with only one HTTP fetch and/or without additional logic in your own code.
If you emit([time, name]) you would be able to query startkey=[timeA]&endkey=[timeB]&group_level=2 to get items between timeA and timeB grouped where their timestamp and name were identical. You could then post-process this to add up whenever the names matched, but the initial result set might be larger than you want to handle.
An alternative would be to emit([name,time]). Then you could first query with group_level=1 to get a list of names [if your application doesn't already know what they'll be]. Then for each one of those you would query startkey=[nameN]&endkey=[nameN,{}]&group_level=2 to get the summary for each name.
(Note that in my query examples I've left the JSON start/end keys unencoded, so as to make them more human readable, but you'll need to apply your language's equivalent of JavaScript's encodeURIComponent on them in actual use.)
You can not make a view onto a view. You need to write another map-reduce view that has the filtering and makes the grouping in the end. Something like:
map:
function(doc) {
if (doc.timestamp > start and doc.timestamp < end ) {
emit(doc.name, doc.value);
}
}
reduce:
function(key, values, rereduce) {
return sum(values);
}
I suppose you can not store this view, and have to put it as an ad-hoc query in your application.