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Search found 549 results on 22 pages for 'nosql'.

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  • Simplest database implementation

    - by MaX
    I am looking for a really simple database implementation; basically one with no complex parsing SQL engine. What I am looking for is something demonstrating B+ trees and ACID storage (Suitable for educational purposes). What I have found up-till now form my current searches was hamster-db. I am looking for something even simpler with a smaller code-base. If there is any such opensource project in your knowledge please let me know.

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  • NO-SQL reliable for small bussines app?

    - by mamcx
    I'm deciding between go for a NON-SQL engine or a regular SQL one for a document managment system for small bussines. I have experience with firebird/sql server and found a good track of reliability (specially with firebird). This market is full of crappy "servers" (clon-made PC, the mayority), cheap harddisk, rarely use of RAID or anything like that, some are in locations where a power-off is normal, some not have a UPS, etc... (I will include off-site auto-backup to external servers, but that no change the internal setup). (I know about end-user education about such proper setups, but is stupid depend on that, so stick to te point) From the desing point of view, a schema-less database is the way to go for my system, but, I worry if any of the actual solutions (MongoDb, Tokyo Cabinet, etc) are like firebird and survice crash, malfunctions & abuse so data corruption is very rare. The plan is store the office documents there & provide a central repository.

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  • Looking for efficient scaling patterns for Silverlight application with distributed text-file data s

    - by Edward Tanguay
    I'm designing a Silverlight software solution for students and teachers to record flashcards, e.g. words and phrases that students find while reading and errors that teachers notice while teaching. Requirements are: each person publishes his own flashcards in a file on a web server, e.g. http://:www.mywebserver.com/flashcards.txt other people subscribe to that person's flashcards by using a Silverlight flashcard reader that I have developed and entering the URLs of flashcard files they want to subscribe to, URLs and imported flashcards being saved in IsolatedStorage the flashcards.txt file has the following simple format: title, then blocks of question/answers: Jim Smith's flashcards from English class 53-222, winter semester 2009 ==fla Das kann nicht sein. That can't be. ==fla Es sei denn, er kommt nicht. Unless he doesn't come. The user then makes public the URL to his flashcard file and other readers begin reading in his flashcards. In order to lower the bar for non-technical users to contribute, it will even be possible for them to save this text in a Google Document, which they publish and distribute the URL. The flashcard readers will then recognize it is a google document and perform the necessary screen scraping to get at the raw text. I have two technical questions about this approach: What is a best way to plan now for scalability issues: e.g. if your reader is subscribed to 10 flashcard files that are each 200K, it will have to download 2MB of text just to find out if any new flashcards are available. Or can I somehow accurately and consistently get at the last update date/time of text files on servers and published google docs? Each reader will have the ability to allow the person to test himself on imported flashcards and add meta information to them, e.g. categorize them, edit them, etc. This information will be stored in IsolatedStorage along with the important flashcards themselves. What is a good pattern to allow these readers to share and synchronize this meta data, e.g. so when you are looking at a flashcard you can see that 5 other people have made corrections to it. The best solution I can think of now is that the Silverlight readers will have to republish their data to a central database, but then there is the problem of uniquely identifying each flashcard, the best approach seems to be URL + position-in-file, or even better URL + original text of both question and answer fields, but both of these have their obvious drawbacks. The main requirement is that the bar for participation is kept as low as possible, i.e. type text in a google document, publish it, distribute the URL, and you're publishing within the flashcard community. So I want to come up with the most efficient technical solutions in order to compensate for the lack of database, lack of unique ids, etc. For those who have designed or developed similar non-traditional, distributed database projects like this, what advice, experience or best-practice tips you can share on the above two points?

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  • 'schema' design for a social network

    - by Alan B
    I'm working on a proof of concept app for a twitter style social network with about 500k users. I'm unsure of how best to design the 'schema' should I embed a user's subscriptions or have a separate 'subscriptions' collection and use db references? If I embed, I still have to perform a query to get all of a user's followers. e.g. Given the following user: { "username" : "alan", "photo": "123.jpg", "subscriptions" : [ {"username" : "john", "status" : "accepted"}, {"username" : "paul", "status" : "pending"} ] } to find all of alan's subscribers, I'd have to run something like this: db.users.find({'subscriptions.username' : 'alan'}); from a performance point of view, is that any worse or better than having a separate subscriptions collection? also, when displaying a list of subscriptions/subscribers, I am currently having problems with n+1 because the subscription document tells me the username of the target user but not other attributes I may need such as the profile photo. Are there any recommended practices for such situations? thanks Alan

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  • Is sstable2json broken in Cassandra 0.6.0-beta3?

    - by knorv
    I'm getting NullPointerException:s when using sstable2json in Cassandra 0.6.0-beta3: $ bin/sstable2json .../cassandra/data/system/LocationInfo-1-Data.db Exception in thread "main" java.lang.NullPointerException at java.util.Arrays$ArrayList.<init>(Arrays.java:3357) at java.util.Arrays.asList(Arrays.java:3343) at org.apache.cassandra.tools.SSTableExport.export(SSTableExport.java:255) at org.apache.cassandra.tools.SSTableExport.export(SSTableExport.java:299) at org.apache.cassandra.tools.SSTableExport.export(SSTableExport.java:323) at org.apache.cassandra.tools.SSTableExport.main(SSTableExport.java:367) I've had no problems with sstable2json when using Cassandra 0.5. Is sstable2json broken in Cassandra 0.6.0-beta3 or am I doing something wrong?

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  • Which Database to choose?

    - by Sundar
    I have the following criteria Database should be protected with a username and password. It should not be possible to copy the database file and use it else were like MS Access. There will be no central database server. Each machine will run their own database server locally and user will initiate synchronization. Concept is inspired from distributed version control system like Git. So it should have good replication support. Strong consistency is not needed. Users will synchronize each other database when they need. In case of conflicts it should be possible to find the conflict and present it (from application) to the user for fixing it. Revisions of data if available it will be good. e.g. Entire history of change to a invoice. I explored document oriented database and inclined towards the same. But I dont know what to choose. Database is small it will not reach even 1GB in the next few years (say 3 years). Please feel free to suggest any database which you think might be suitable. Any pointers is highly appreciated. Thanks in advance.

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  • Graph databases and Php

    - by stagas
    I want to use a graph database using php. Can you point out some resources on where to get started? Is there any example code / tutorial out there? Or are there any other methods of storing data that relate to each other in totally random/abstract situations? Very abstract example of the relations needed: John relates to Mary, both relate to School, John is Tall, Mary is Short, John has Blue Eyes, Mary has Green Eyes, query I want is which people are related to 'Short people that have Green Eyes and go to School' - answer John It is possible in MySQL but it would require a fixed set of attributes/columns for each item and a complex non-flexible query, instead I need every attribute to be an item by itself and instead of 'belonging' to something, to be 'related' to something.

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  • Is it easy to switch from relational to non-relational databases with Rails?

    - by Tam
    Good day, I have been using Rails/Mysql for the past while but I have been hearing about Cassandra, MongoDB, CouchDB and other document-store DB/Non-relational databases. I'm planning to explore them later as they might be better alternative for scalability. I'm planning to start an application soon. Will it make a different with Rails design if I move from relational to non-relational database? I know Rails migrations are database-agnostic but wasn't sure if moving to non-relational will make difference with design or not.

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  • Cassandra API equivalent of "SELECT ... FROM ... WHERE id IN ('...', '...', '...');"

    - by knorv
    Assume the following data set: id age city phone == === ==== ===== alfred 30 london 3281283 jeff 43 sydney 2342734 joe 29 tokyo 1283881 kelly 54 new york 2394929 molly 20 london 1823881 rob 39 sydney 4928381 To get the following result set .. id age phone == === ===== alfred 30 3281283 joe 29 1283881 molly 20 1823881 .. using SQL one would issue .. SELECT id, age, phone FROM dataset WHERE id IN ('alfred', 'joe', 'molly'); What is the corresponding Cassandra API call that would yield the same result set in one command?

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  • Does this schema sound better suited for a document-oriented data store or relational?

    - by Blaine LaFreniere
    Disclaimer: let me know if this question is better suited for serverfault.com I want to store information on music, specifically: genres artists albums songs This information will be used in a web application, and I want people to be able to see all of the songs associated to an album, and albums associated to an artist, and artists associated to a genre. I'm currently using MySQL, but before I make a decision to switch I want to know: How easy is scaling horizontally? Is it easier to manage than an SQL based solution? Would the above data I want to store be too hard to do schema-free? When I think association, I immediately think RDBMSs; can data be stored in something like CouchDB but still have some kind of association as stated above?

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  • When NOT to use Cassandra?

    - by JimJim
    There has been a lot of talk related to Cassandra lately. Twitter, Digg, Facebook, etc all use it. When does it make sense to: use Cassandra, not use Cassandra, and use a RDMS instead of Cassandra.

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  • Berkeley DB java edition, any LGPL or BSD alternatives in Java?

    - by Ali
    Hi All, I am dealing with a huge dataset consisting of key-value pairs. The queries are always in the form of range queries on the key space (keys are numbers) hence any persistent B-Tree like structure will handle the situation. I would like to use BDB-Java Edition but the product is closed source and my company doesn't want to buy BDB-JE License. I am wondering, would you please share your experience with any non-GPL java based key-value storage system. Thanks, -A

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  • Cassandra random read speed

    - by Jody Powlette
    We're still evaluating Cassandra for our data store. As a very simple test, I inserted a value for 4 columns into the Keyspace1/Standard1 column family on my local machine amounting to about 100 bytes of data. Then I read it back as fast as I could by row key. I can read it back at 160,000/second. Great. Then I put in a million similar records all with keys in the form of X.Y where X in (1..10) and Y in (1..100,000) and I queried for a random record. Performance fell to 26,000 queries per second. This is still well above the number of queries we need to support (about 1,500/sec) Finally I put ten million records in from 1.1 up through 10.1000000 and randomly queried for one of the 10 million records. Performance is abysmal at 60 queries per second and my disk is thrashing around like crazy. I also verified that if I ask for a subset of the data, say the 1,000 records between 3,000,000 and 3,001,000, it returns slowly at first and then as they cache, it speeds right up to 20,000 queries per second and my disk stops going crazy. I've read all over that people are storing billions of records in Cassandra and fetching them at 5-6k per second, but I can't get anywhere near that with only 10mil records. Any idea what I'm doing wrong? Is there some setting I need to change from the defaults? I'm on an overclocked Core i7 box with 6gigs of ram so I don't think it's the machine. Here's my code to fetch records which I'm spawning into 8 threads to ask for one value from one column via row key: ColumnPath cp = new ColumnPath(); cp.Column_family = "Standard1"; cp.Column = utf8Encoding.GetBytes("site"); string key = (1+sRand.Next(9)) + "." + (1+sRand.Next(1000000)); ColumnOrSuperColumn logline = client.get("Keyspace1", key, cp, ConsistencyLevel.ONE); Thanks for any insights

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  • Neo4j Reading data / performing shortest path calculations on stored data

    - by paddydub
    I'm using the Batch_Insert example to insert Data into the database How can i read this data back from the database. I can't find any examples of how i do this. public static void CreateData() { // create the batch inserter BatchInserter inserter = new BatchInserterImpl( "var/graphdb", BatchInserterImpl.loadProperties( "var/neo4j.props" ) ); Map<String,Object> properties = new HashMap<String,Object>(); properties.put( "name", "Mr. Andersson" ); properties.put( "age", 29 ); long node1 = inserter.createNode( properties ); properties.put( "name", "Trinity" ); properties.remove( "age" ); long node2 = inserter.createNode( properties ); inserter.createRelationship( node1, node2, DynamicRelationshipType.withName( "KNOWS" ), null ); inserter.shutdown(); } I would like to store graph data in the database, graph.makeEdge( "s", "c", "cost", (double) 7 ); graph.makeEdge( "c", "e", "cost", (double) 7 ); graph.makeEdge( "s", "a", "cost", (double) 2 ); graph.makeEdge( "a", "b", "cost", (double) 7 ); graph.makeEdge( "b", "e", "cost", (double) 2 ); Dijkstra<Double> dijkstra = getDijkstra( graph, 0.0, "s", "e" ); What is the best method to store this kind data with 10000's of edges. Then run the Dijskra algorighm to find shortest path calculations using the stored graph data.

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  • Which CouchDB API to use for Rails?

    - by Matt Baker
    I am currently investigating possible applications of CouchDB on my current project (written in Rails) and would like to get some feedback from people who have actually used these APIs. Which would you recommend and why? ActiveCouch CouchFoo CouchRest CouchRest-Rails CouchPotato

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  • The usage of Cassandra's internal keyspace "system"

    - by knorv
    The default Cassandra systems keyspace system is present in all Cassandra installations. Judging from the output of the describe keyspace command the keyspace it is used partly for "persistent metadata for the local node" (LocationInfo) and partly for "hinted handoff data". What persistent metadata for the local node is stored in system/LocationInfo? What is the definition of hinted handoff in Cassandra terminology? What hinted handoff data is stored in the system keyspace?

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  • What permissions do I need to grant to run RavenDB in Server mode?

    - by dalesmithtx
    I'm reading through Rob Ashton's excellent blog post on RavenDB: http://codeofrob.com/archive/2010/05/09/ravendb-an-introduction.aspx and I'm working through the code as I read. But when I try to add an index, I get a 401 error. Here's the code: class Program { static void Main(string[] args) { using (var documentStore = new DocumentStore() { Url = "http://localhost:8080" }) { documentStore.Initialise(); documentStore.DatabaseCommands.PutIndex( "BasicEntityBySomeData", new IndexDefinition<BasicEntity, BasicEntity>() { Map = docs => from doc in docs where doc.SomeData != null select new { SomeData = doc.SomeData }, }); string entityId; using (var documentSession = documentStore.OpenSession()) { var entity = new BasicEntity() { SomeData = "Hello, World!", SomeOtherData = "This is just another property", }; documentSession.Store(entity); documentSession.SaveChanges(); entityId = entity.Id; var loadedEntity = documentSession.Load<BasicEntity>(entityId); Console.WriteLine(loadedEntity.SomeData); var docs = documentSession.Query<BasicEntity>("BasicEntityBySomeData") .Where("SomeData:Hello~") .WaitForNonStaleResults() .ToArray(); docs.ToList().ForEach(doc => Console.WriteLine(doc.SomeData)); Console.Read(); } } } It throws the 401 error when on the line that makes the PutIndex() call. Any ideas what permissions I need to apply? And where I need to apply them?

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  • Problem with Couchdb :/

    - by 2x2p1p
    Hi guys. I really tried, tried so hard but i cant understand couchdb :( I must record the contact of several people, should i put every contact in a single document ? codeviewer.org/view/code:df8 Or in different documents ? codeviewer.org/view/code:df9 I confused, can somebody help me ? Thanks.

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  • Graph-structured databases and Php

    - by stagas
    I want to use a graph database using php. Can you point out some resources on where to get started? Is there any example code / tutorial out there? Or are there any other methods of storing data that relate to each other in totally random/abstract situations? - Very abstract example of the relations needed: John relates to Mary, both relate to School, John is Tall, Mary is Short, John has Blue Eyes, Mary has Green Eyes, query I want is which people are related to 'Short people that have Green Eyes and go to School' - answer John - Another example: TrackA -> ArtistA -> ArtistB -> AlbumA -----> [ label ] -> AlbumB -----> [ A ] -> TrackA:Remix -> Genre:House -> [ Album ] -----> [ label ] TrackB -> [ C ] [ B ] Example queries: Which Genre is TrackB closer to? answer: House - because it's related to Album C, which is related to TrackA and is related to Genre:House Get all Genre:House related albums of Label A : result: AlbumA, AlbumB - because they both have TrackA which is related to Genre:House - It is possible in MySQL but it would require a fixed set of attributes/columns for each item and a complex non-flexible query, instead I need every attribute to be an item by itself and instead of 'belonging' to something, to be 'related' to something.

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  • Building a News-feed that comprises posts "created by user's connections" && "on the topics user is following"

    - by aklin81
    I am working on a project of Questions & Answers website that allows a user to follow questions on certain topics from his network. A user's news-feed wall comprises of only those questions that have been posted by his connections and tagged on the topics that he is following(his expertise topics). I am confused what database's datamodel would be most fitting for such an application. The project needs to consider the future provisions for scalability and high performance issues. I have been looking at Cassandra and MySQL solutions as of now. After my study of Cassandra I realized that Simple news-feed design that shows all the posts from network would be easy to design using Cassandra by executing fast writes to all followers of a user about the post from user. But for my kind of application where there is an additional filter of 'followed topics', (ie, the user receives posts "created by his network" && "on topics user is following"), I could not convince myself with a good schema design in Cassandra. I hope if I missed something because of my short understanding of cassandra, perhaps, can you please help me out with your suggestions of how this news-feed could be implemented in Cassandra ? Looking for a great project with Cassandra ! Edit: There are going to be maximum 5 tags allowed for tagging the question (ie, max 5 topics can be tagged on a question).

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