nosql

问题 I find Firebase Database sample very helpful, but I noticed something which worries me a little bit. I mean in this example user can give star to the post, something like "Like it" on Facebook. In provided sample they nested stars into post, so we have sample object like this: "post_id" : { "author": "username", "body": "Some content", "starCount": 1 "stars" : { "user_id_who_gave_star" : "true" } "title": "Some title", "uid": "author_id" } Such solution has many advantages, like e.g. we can

问题 Is there any open source library (any programming language) that helps to load data from any data source (file, SQL db, NoSQL db, etc.) and store it into any other data repository? I've checked some ETL libraries like Talend or Octopus but they only deal with SQL databases. 回答1: Try https://flywaydb.org/, since NoSQL has different nature than Relational Structure you should write your own converter { "item_id" : 1, "tags" : ["a","b","c"] } How this should be translated into RDBMS? you can use

问题 I am trying to replicate a couchdb database using filters. This is my code that I am running using Command Prompt: curl -H 'Content-Type: application/json' -X POST http://localhost:5984/_replicate -d '{"source": "http://localhost:5984/source_database", "target": "http://localhost:5984/testdb", "create_target": true, "continuous": true, "doc_ids": ["000803f8-7f61-4afd-b532-8e6c1028d965"]}' I get the following error: Illegal database name, Reason, name:'testdb, '. For some reason, an unwanted

问题 I am waiting new aggregating framework of Mongodb. New aggregation framework query style documented in this address and it is written at top The Aggregation Framework was first available in MongoDB 2.1.0. So where I can download it for try that version ? 回答1: Right there: http://www.mongodb.org/downloads In the "Development (unstable)" section. 回答2: The "Development Release" nightly builds available at http://www.mongodb.org/downloads include the aggregation framework. 来源： https:/

问题 I successfully set up a MongoDB Database and my Java program is connecting to it fine. However, when I try to save an instance of this class, I get an error: @Data public class NormalUser extends User implements Serializable { private static final long serialVersionUID = 1324235L; public NormalUser(final String name, final String surname, final String address, final String dni, final Gender gender, final String bankAccount) { super(name, surname, address, dni, gender, bankAccount, Role.NORMAL

问题 I used this build to install redis on my windows7: https://github.com/rgl/redis (git) http://ruilopes.com/redis-setup/binaries/redis-2.4.6-setup-64-bit.exe (binary) Service has been installed sucessfully, but it doesn't start: The message says: 'Redis Server service on local computer was started and then stopped'. logs folder is empty. redis-server.exe starts properly without service. How can I fix this? Propose any other working dist. plz if you know it. 回答1: Ran into a similar issue on

问题 I am using Laravel4 PHP Framework, my web application has to handle JSON format APIs. First part of My problem is, each time when i get a subscription, deviceID and listID (where list ID is the the list which was subscribed by the device having deviceID) is received by the web application. For each deviceID received we have to create a blob having deviceID like { deviceID:........, subscription:[{listID:1},{listID:2}.......] } when the same device subscribe multiple list i have to update

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 3 years ago . I want to handle nested category in Mongo and Meteor framework for several Ads. For example like this: Ads object have category field like this: MainCategory_1 > SubCategory_1.1 > SubCategory_1.1.1 > SubCategory_1.1.1.1 > { Ad_1 HERE } > SubCategory_1.2 > SubCategory_1.2.1 >

问题 i'm ok with insertion and selecting, but when i'm trying to retrieve particular document from table while using JSON_VAL index, i'm facing error with sql code -440. 来源： https://stackoverflow.com/questions/42155988/db2-json-facing-440-sql-error-while-using-json-val-for-indexing

问题 I read a lot about different NoSQL databases but I'm still undecided which solution would be the most appropriate in my situation - probably because I have no experience with NoSQL databases - except REDIS, which I'm using for caching. In my scenario I have to store time-based historic values (mixed float, integer, boolean values based on datapoint) for about 200,000 datapoints. Typically each datapoint will get a new value every 15 minutes, or less, totaling something in the range of a