How to find particular json document details from couchdb
For ex : Database name : employee_mgmt, in that database contains 50 json documents. So i want to find particular employee json documents ( Find by employee id ).
CouchDB does in it self not provide you with collections/buckets, hence all your documents are peers. It's up to you to provide meta-data e.g. by having a property $doctype with a value representing what kind of document it is. This is useful if you are writing maps and e.g. want to create a view (secondary index) returning something applicable only to employees.
Know, if you just want to query by _id you don't need the above. Just do a simple GET with an URI as: http://host:port/databasename/documentid
More information: http://docs.couchdb.org/en/1.6.1/api/document/common.html#get--db-docid
If you want to get a batch of documents matching many _id use the builtin index _all_docs http://docs.couchdb.org/en/1.6.1/api/database/bulk-api.html#post--db-_all_docs
Related
Relatively simple question -- I want to append index-level information onto each document when returning those documents. I do not want to copy that information into each document (makes it harder to adjust that information if it changes). I've found out that you can use the _meta tag to add information to the index level, but now I want it to be appended onto the document when returning results from a search query.
My specific use case is: I have indices that store posts per user (indices are structured as: posts-USER_ID). I'm performing a search across all posts across all user indices (search index: posts-*), and I want to return user information with each index (that user information being a JSON object with fields like username, userColor, displayName).
I see that fields like _index and _type are index-level and returned with each document automatically. I essentially want to return a custom field as well. As said above I've been able to successfully append this user information on _meta for an index but I can't figure out how to append it to documents returned from that index (for my search results from that multi-index query).
The reason I want this is because I need user information with post information on search (to display various things, username, displayName, coloring posts in the userColor). Ideally I'd prefer not to have to perform another query for each search result to retrieve user information (for each document result, querying the user that created that post -- seems expensive). I also would not like to copy that user information in each document in an index (so under a posts-USERID index adding a creator field with user information). But that seems insanely repetitive (as the indices are already partitioned per user) and when the user updates information that is very very expensive (would have to iterate through each document in "their" index and change their information.
What do I do / help!
(linked question in the elastic discussion page: https://discuss.elastic.co/t/how-to-append-index-level-information-to-documents-when-returning-search-results/262923)
I am creating an index in Azure Search Service and looking for a way to allow unknown fileds to be submitted. My documents are semi structured, meaning I know few fields up front. But I want the flexibility to be able to add documents with additional fields.
for example:
{
"name":"name1",
"description":"description"
"unknown,_simple":"test",
"unknown_complex": [{
"male":20,
"female":30
}]
}
In the above example, I know about Name and Description fields so they are added to the index with correct mapping. But unknow_simple and unknown_complex types are not know. Users can submit these when they are creating the documents. Right now Azure Search Rest API is complaining with the following error message
The request is invalid. Details: parameters : A resource without a
type name was found, but no expected type was specified. To allow
entries without type information, the expected type must also be
specified when the model is specified
How can I achieve this? Thank you for you help.
Per my understanding , you want to design your index designed as semi structured , "name" and "description" are two fixed fields and with fixed data type. There will be two flexible fields that you are not sure about its data type. In fact, you can define its data type as string.
Let's say you want to store a json object in that filed, just stringizing your json object so that you can set this string value in that field. Converting this value to json when next time you need it .
If you want to query certain field of json object in your Dynamic field, you can just use the json string fragment as query key to search , just as below :
Lets assume that "Description" filed is my Dynamic field and its value is a json string , I can use the key fragment to get result I want. But it is not so elegant though .
We want to check if a document already exists in the database with the same fields and values of a new object we are trying to save to prevent duplicated item.
Note: This question is not about updating documents or about duplicated document IDs, we only check the data to prevent saving a new document with the same data of an existing one.
Preferably we'd like to accomplish this with Mango/Cloudant queries and not rely on views.
The idea so far is:
1) Scan the the data that we are trying to save and dynamically create a selector that matches that document's structure. (We can't have the selectors hardcoded because we have types of many documents)
2) Query de DB with for any documents matching that selector to if any document already exists that matches those criteria.
However I wonder about the performance of this approach since many of the selector fields will not be indexed.
I also much rather follow best practices than create something out of the blue, but haven't been able to find any known solutions for this specific scenario.
If you happen to know of any, please share.
Option 1 - Define a meaningful ID for your documents
The ID could be a logical coposition or a computed hash from the values that should be unique
If you want to check if a document ID already exists you can use the HEAD method
HEAD /db/docId
which returns 200-OK if the docId exits on the database.
If you would like to check if you have the same content in the new document and in the previous one, you may use the Validate Document Update Function which allows to compare both documents.
function(newDoc, oldDoc, userCtx, secObj) {
...
}
Option 2 - Use content hash computed outside CouchDB
Before create or update a document a hash should be computed using the values of the attributes that should be unique.
The hash is included in the document in a new attribute i.e. "key_hash"
Create a mango index using the "key_hash" attribute
When a new doc should be inserted, the hash should be computed and find for documents with the same hash value using a mango expression before the doc is inserted.
Option 3 - Compute hash in a View
Define a view which emit the computed hash for each document as key
Couchdb Javascript support does not include hashing functions, this could be difficult to include in a design document.
Use erlang to define the map function, where you can access to the erlang support for hashing.
Before creating a new document you should query the view using a the hash that you need to compute previously.
One solution would be to take Juanjo's and Alexis's comment one step further.
Select the keys you wish to keep unique
Put the values in a string and generate a hash
Set the document's _id to that hash
PUT the document on the database.
check return for failure
If another document already exists on the database with the same _id value, the PUT request will fail.
I have a requirement where in there are 3 different fields in a document, ie id, l1ser(multi-values), l2ser(multi-valued).
The UI needs to display the l2ser belonging to the particular l1ser for a particular id,(the user can select multiple l1ser and all the l2ser associated with all of the l1ser should be listed)
For instance,
l1ser : school, l2ser : staffs,students,classrooms
l1ser : IT company, l2ser : cisco, anz,cts
You can use the keys query parameter for fetching multiple view results at once. Details can be found in the CouchDB docs.
It depends on the view however if this is the correct solution. If you provide some correct JSON documents and your view code, I'll take a closer look.
I am currently working with the Algolia search API and I am unable to figure out how I would limit the results by key value searching + query string. By this i mean this.
I have a list of properties.
Each property belongs to a client.
Within the application If i am looking at a client information card and I want to search for a property that client owns It would make more sense to limit the results to the client and then look for the query string.
I am using MongoDB as my DB and storing the client id as a sub document like so
//Property Document
{
_id : "randomID"
client : {
_id : "randomID",
name : "ClientName"
}
}
If you want to restrict the search to a specific client, I would go for facet filtering to restrict the search to that client only.
Add client._id in the attributesForFaceting in your index settings
Filter your searches with the facetFilters=client._id:MYCLIENTID query parameter
Then, you should also take a look at the Secured API keys which are able to encode such restriction in a secure way (so the end-user cannot patch the JS code and work-around the filtering).
There is parameter called restrictSearchableAttributes[link] to restrict, at query time, search to some attributes only. Nevertheless, in your case I think you'd get more accurate results by putting each client info into a different record (+ the info of the related document).