nosql

问题 I have a cassandra database with a keyspace that looks like: CREATE TABLE custumer_events_service.events( acceptFirstContactDuration decimal, currentTime timestamp, visitorIdentifier text, PRIMARY KEY (visitorIdentifier, currentTime) ) WITH CLUSTERING ORDER BY (currentTime DESC); And a python dict {u'acceptFirstContactDuration': 0, u'currentTime': u'2016-02-18T11:51:55.468Z', u'12eca72928845aae26268f431b8c75b2564d7919c916e',} Is there a way to insert this dict directly with cassandra-driver ?

问题 Is there anyone who had noted that Couchbase changes the numerical value of a property, over a certain limit, when recording a Json document? Here is an example. For this test, I use the live input via the couchbase web interface. The property "inputValue" corresponds to the value entered in the property "valueAfterSave" before clicking the save button. The property "valueAfterSave" corresponds to the value after the save. To a number with 16 digits, it's good: { "inputValue":

问题 I've recently started to play around with Cassandra. My understanding is that in a Cassandra table you define 2 keys, which can be either single column or composites: The Partitioning Key: determines how to distribute data across nodes The Clustering Key: determines in which order the records of a same partitioning key (i.e. within a same node) are written. This is also the order in which the records will be read. Data from a table will always be sorted in the same order, which is the order

问题 I have a noSQL db with products. These products obviously have some characteristics and I can filter the products out by their properties. How does this work with tags? More specifically, how should I structure the nodes such that I can filter out items with a specific tag? Firebase Follow up if you are familiar with Firebase .equalTo(): how would I structure my FB db and how would I query out items with a specic tag? One thing I was thinking of is to have seperate properties for the nodes, e

问题 I am new to Firebase and I want to use their Database, but there seems to be some issues with the encoding. Here is my example json with UTF-8 Encoding: [ { "Stack": "This is madness! äüöß ", "Overflow": 666 } ] And this is the result, when I import the json to Firebase: What can I do to import characters like "äüöß" to the Firebase Database? Thank you! 回答1: thank you for your answers. I used the Web Console to import the json (https://console.firebase.google.com/project/[projectname]

问题 Suppose I have Student and Teacher in a many to many relationship. If I just want to find out all the teachers for a given student or vice versa I generally model it by using embedded Object Ids. For example if teacher has a property studentIds which is an array of student Object Ids then that is enough information to do all the queries you need. However suppose that a student can give a teacher a rating. How should this rating fit into the model? At the moment I do the following: Inside

问题 In relation to my other question about modelling a real user-facing tree structure (Using firebase tree structure to represent a "document outline" structure directly), I was thinking of putting in place a generic approach to "symlinking", at certain nesting levels, to overcome the 32 nesting levels limitation and the need to fetch all sub-nodes at once. Are there some "best-practices" for "symlinking" in firebase? E.g.: syntax (contents, key-value structure) for a firebase node which would

问题 Here is an example from Redis intro: $ redis-cli rpush messages "Hello how are you?" OK $ redis-cli rpush messages "Fine thanks. I'm having fun with Redis" OK $ redis-cli rpush messages "I should look into this NOSQL thing ASAP" OK $ redis-cli lrange messages 0 2 1. Hello how are you? 2. Fine thanks. I'm having fun with Redis 3. I should look into this NOSQL thing ASAP Below they write the following: As you can guess from the example above, lists could be used in order to implement a chat

问题 I am having some trouble trying to update some fields of a subdocument inside a subdocument in mongodb . First of all, let's find exactly the document I need to update to see how the document structure looks like: // query: db.getCollection('collection').find({ application: ObjectId("568b3a2feaa4171d03734776"), _id: ObjectId("568b3a2feaa4171d03734779"), status: 'sent', 'mailingList.recipients.email': 'example@example.com' // an index }, { 'mailingList.$.recipients': true }); // query result:

问题 I have a json structure something like { foo:"bar", keyPhrases:[ {key: "random thing", value: 5}, {key: "another random", value: 3} ] } How can i do a word query on keyPhrases.key ? I tried qb.word('keyPhrases.key', 'random') or qb.word(qb.property('keyPhrases.key'), 'random') and it does not work. Any ideas? I know this is possible with a QBE but for the Marklogic NodeJS API you can`t specify a collection, and I need to. 回答1: You need qb.scope(). var ml = require('marklogic'); var conn =