couchdb

问题 I have multiple CouchDB documents representing a timestamp with a property userId and tag (a user can have n timestamps and assign each one a tag). I want to query CouchDB by a specific userId and get a sorted list of tags the user has used (sorted by occurrence). How would the view look like? If I want to get a list of all tags sorted by occurrence (no matter from which user) or if I assume that there are only documents with the same userId, I would make it like so: Map: function(doc) { if

问题 I need to create a CouchDB user which can only read documents from any database but can't write any of them. As far as I'm concerned, it is not what is supported by default (user types are described here). As the wiki says, access rights are given per database, so it seems what I am trying to do is not the best way to use CouchDB. Anyway, it would be great to do that. Could you please give me some tips on how to implement that? 回答1: You will need to put a design doc in each database you want

问题 I am wondering that how your data is safe when an admin can change the latest state in Couchdb using Fauxton or cURL provided by Couchdb directly. According to my understanding Hyperledger Fabric provides immutable data feature and is best for fraud prevention(Blockchain feature). The issue is :- I can easily change the data in couchdb and when I query from my chaincode it shows the changed data. But when I query ledger by using GetHistoryForKey() it does not shows that change I made to

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 4 years ago . I've followed the CouchDB project with interest over the last couple of years, and see it is now an Apache Incubator project. Prior to that, the CouchDB web site was full of do not use for production code type disclaimers, so I'd done no more than keep an eye on it. I'd be

问题 I am stuck between these two NoSQL databases. In my project I will be creating a database within a database. For example, I need a solution to create dynamic tables. So users can create tables with columns and rows. I think either MongoDB or CouchDB will be good for this, but I am not sure which one. I will also need efficient paging as well. 回答1: Of C, A & P (Consistency, Availability & Partition tolerance) which 2 are more important to you? Quick reference, the Visual Guide To NoSQL Systems

问题 I'm thinking that UTC time strings like 2011-01-26 21:41:09 +0000 might be okay since they sort correctly if they are used in a view key, but storing the time zone (e.g. 2011-01-26 16:41:09 -0500 ) would make the document more readable. Converting the date into an epoch integer seem the least appealing from a readability standpoint, but maybe best for performance (or does it make a difference?). What's the recommended practice here? 回答1: Time is a one-dimensional thing. A timestamp plus

问题 This question already has answers here : Can I optionally turn off the JsonIgnore attribute at runtime? (3 answers) Closed last year . I am currently using the same C# DTOs to pull data out of CouchDB, via LoveSeat which I am going to return JSON via an ASP MVC controller. I am using the NewtonSoft library to seralise my DTOs before sending them down through the controller. However, as CouchDB also uses NewtonSoft it is also respecting the property level NewtonSoft attributes such as

问题 http://wiki.apache.org/couchdb/Document_Update_Handlers CouchDB ( 0.10 and above ) supports in-place updates now. I'm having trouble understanding how it works. I tried to use the example provided but I couldn't get it to work. Can someone provide some examples and uris used to access the in-place updates. Thanks 回答1: The example function in-place is not the same as "in-place" updates in other databases. CouchDB still uses an append-only architecture; document update handlers still create a

问题 Why should I use document based database like CouchDB instead of using relational database. Are there any typical kinds of applications or domains where the document based database is more suitable than the relational database? 回答1: Probably you shouldn't :-) The second most obvious answer is you should use it if your data isn't relational. This usually manifests itself in having no easy way to describe your data as a set of columns. A good example is a database where you actually store paper

问题 I need to do transactions (begin, commit or rollback), locks (select for update). How can I do it in a document model db? Edit: The case is this: I want to run an auctions site. And I think how to direct purchase as well. In a direct purchase I have to decrement the quantity field in the item record, but only if the quantity is greater than zero. That is why I need locks and transactions. I don't know how to address that without locks and/or transactions. Can I solve this with CouchDB? 回答1: