nosql | 易学教程

What database would you use for logging (i.e. als logfile replacement)

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问题 After analyzing some gigabytes of logfiles with grep and the like I was wondering how to make this easier by using a database to log the stuff into. What database would be appropiate for this purpuse? A vanillia SQL database works, of course, but provides lots of transactional guarantees etc. which you don't need here, and which might make it slow if you work with gigabytes of data and very fast insertion rates. So a NoSQL database that could be the right answer (compare this answer for some

Neo4j (or any other graph database) modeling

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问题 I'm starting to work with graph databases, and in my team we've started modeling a graph for our software. The problem comes when we try to "document" the model, to see the structure of our database. With SQL databases you only have to look at the SQL schema. We've spent some time reading neo4j blogs and documentation, but we've seen that the usual way to show how a graph works is with a minimal graph showing some sample data (Random samples: sample1, sample2, etc). That's great for

HBase row key design for monotonically increasing keys

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问题 I've an HBase table where I'm writing the row keys like: <prefix>~1 <prefix>~2 <prefix>~3 ... <prefix>~9 <prefix>~10 The scan on the HBase shell gives an output: <prefix>~1 <prefix>~10 <prefix>~2 <prefix>~3 ... <prefix>~9 How should a row key be designed so that the row with key <prefix>~10 comes last? I'm looking for some recommended ways or the ways that are more popular for designing HBase row keys. 回答1: How should a row key be designed so that the row with key ~10 comes last? You see the

Can redis fully replace mysql?

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问题 Simple question, could I conceivably use redis instead of mysql for all sorts of web applications: social networks, geo-location services etc? 回答1: Nothing is impossible in IT. But some things might get extremely complicated. Using key-value storage for things like full-text search might be extremely painfull. Also, as far as I see, it lack support for large, clustered databases: so on MySQL you have no problems if you grow over 100s of Gb in Database, and on Redis... Well, it will require

我所经历的大数据平台发展史（四）：互联网时代 • 下篇

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编者按：本文是松子（李博源）的大数据平台发展史系列文章的第四篇（共四篇），本系列以独特的视角，比较了非互联网和互联网两个时代以及传统行业与非传统行业。是对数据平台发展的一个回忆，对非互联网、互联网，从数据平台的用户角度、数据架构演进、模型等进行了阐述。在互联网时代被弱化的数据模型谈起数据模型就不得不提传统数据平台架构发展，我相信很多朋友都晓得传统数据平台的知识，其架构演进简单一句话说“基本上可以分为五个时代、四种架构”，但是到了互联网时代因为大数据快速膨胀与数据源类型多样化特点，从高阶架构上来看大约从传统数据平台第三代架构开始延续的，但是往后的发展从我自己的这一点知识上很难对互联网的数据平台做架构归类。但是从数据平台建设与服务角色上还是有章可循的。就像上篇分享到那样，类比两个行业，互联网企业中员工年龄比非互联网企业的要年轻、受教育程度、对计算机的焦虑程度明显比传统企业要低、还偶遇其它各方面的缘故，导致了数据平台所面对用户群体与非互联网数据平台有所差异化。传统行业与互联网行业数据平台用户特性我只选择前文章的两张图来表示 (点击放大图像) (点击放大图像) 在传统数据平台要背后有一个完整数据仓库团队去服务业务方，业务方嗷嗷待哺的等待被动方式去满足。中低层数据基本不会对业务方开放，所以不管数据模型采用何种建模方式，主要满足当时数据架构规划即可。

RavenDB Attachments - Functionality how to do?

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问题 I have a file input control. <input type="file" name="file" id="SaveFileToDB"/> Lets say I browse to C:/Instruction.pdf document and click on submit. On Submit, I want to save the document in RavenDB and also later retrieve it for download purposes. I saw this link http://ravendb.net/docs/client-api/attachments that says.. do this.. Stream data = new MemoryStream(new byte[] { 1, 2, 3 }); documentStore.DatabaseCommands.PutAttachment("videos/2", null, data, new RavenJObject {{"Description",

How to query all subdocuments

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问题 I'm beginning with MongoDb and nodejs (using mongoose). I have a collection of Stories , each of them can have one or more Tags , it's something like that: { title: "The red fox", content: "The red fox jumps away...", tags: [ { tagname: "fairytale", user: "pippo" }, { tagname: "funny", user: "pluto" }, { tagname: "fox", user: "paperino" } ] }, ... other stories Now I want to make a tag cloud . It means querying Stories for all tags. In a relational world (e.g. MySQL) I would have a Stories

How to query all subdocuments

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Is there a better database than Git (with serializable, immutable, versioned trees)?

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问题 Imagine the data structure behind Git. It's like a confluently persistent data structure, except using hash references instead of traditional pointers. I need Git's data structure, except without any of the working tree and index stuff. And there would be millions of branches, each tracking a handful of other local branches. Commits and merges would occur several thousand times per minute on different threads. Pulls would occur every second. Between libgit2 and jgit I can use Git's data

Is it possible to construct complex queries against noSQL DB

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问题 I have been researching noSQL DB and have not been able to satisfactorily answer this for myself: Is it possible to construct complex queries against noSQL DB? The type of query I'm wondering about would be something like this: select * from DB where vara > x AND varb = 2 AND varc < x AND vard in (x,y,z) AND vare like '%texthere%' AND varf = 2 AND varg = 3 and etc... NOTE: I'm aware that I can't use SQL, as above, what I'm asking is how would I query using the psuedo logic above, in other