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  • What are the best ways to store Graphs in persistent storage

    - by nicoslepicos
    I am wondering what the best ways to store graphs in persistent storage are, for later analysis, search, clustering, etc. I see neo4j being an option, I am curious if there are also other graph databases available. Does anyone have any insights into how larger social networks store their graph based data (or other sites that require the storage of graph like models, e.g. RDF). What about options like Cassandra, or MySQL?

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  • select for update with ruby oci8

    - by ash34
    how do I do a 'select for update' and then 'update' the row using ruby oci8. I have two fields counter1 and counter2 in a table which has only 1 record. I want to select the values from this table and then increment them by locking the row using select for update. thanks.

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  • Normalise this Table?

    - by Abs
    Hello all, I am creating a social bookmarking app. I am having a re-thought of the DB design in the middle of development. Should I normalise the bookmarks table and remove the tag columns that I have into a separate table. I have 10 tags per bookmark and therefore 10 columns per record (per bookmark). It seems to me that breaking the table into two would just mean I would have to do a join but the way I currently have it, its a straight select - but the table doesn't feel right...? Thanks all

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  • question with its query

    - by user329820
    Hi this is my homework and the question is this: List the average balance of customers by city and short zip code (the first five digits of thezip code). Only include customers residing in Washington State (‘WA’). also the Customer table has 5 columns(Name,Family,CustZip,CustCity,CustAVGBal) I wrote the query like below is this correct? SELECT CustCity,LEFT(CustZip,5) AS NewCustZip,CustAVGBal FROM Customer WHERE CustCity = 'WA' THANKS!!

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  • Team working on Drupal - Tips

    - by fighella
    I am working on a Drupal site with a few friends. Obviously we can Version control the code... but what do we do to keep each others databases in check? I have managed to get all the theming into files (contemplate etc), but ideally my views settings, menu settings would be in line also... (Not worried about Content either way as we're just building the framework) Any suggestions?

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  • Exceptions in ASP.MVC

    - by George
    Hello guys, I'm here again with another question about MVC. Here is the deal. I have a simple table/class with an Id and a Name. Names suppossed to be unique, and are modeled like that in the DB. I created my controller and everything just works fine. But if I try to insert a name that already exists, an exception should be thrown. I'm just not finding what is the correct kind of exception and it's namespace. The error must be coming from the DB, so... Any ideas? Thanks

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  • Adding defaults and indexes to a script/generate command in a Rails Template?

    - by charliepark
    I'm trying to set up a Rails Template that would allow for comprehensive set-up of a specific Rails app. Using Pratik Naik's overview (http://m.onkey.org/2008/12/4/rails-templates), I was able to set up a couple of scaffolds and models, with a line that looks something like this ... generate("scaffold", "post", "title:string", "body:string") I'm now trying to add in Delayed Jobs, which normally has a migration file that looks like this: create_table :delayed_jobs, :force => true do |table| table.integer :priority, :default => 0 # Allows some jobs to jump to the front of the queue table.integer :attempts, :default => 0 # Provides for retries, but still fail eventually. table.text :handler # YAML-encoded string of the object that will do work table.text :last_error # reason for last failure (See Note below) table.datetime :run_at # When to run. Could be Time.now for immediately, or sometime in the future. table.datetime :locked_at # Set when a client is working on this object table.datetime :failed_at # Set when all retries have failed (actually, by default, the record is deleted instead) table.string :locked_by # Who is working on this object (if locked) table.timestamps end So, what I'm trying to do with the Rails template, is to add in that :default = 0 into the master template file. I know that the rest of the template's command should look like this: generate("migration", "createDelayedJobs", "priority:integer", "attempts:integer", "handler:text", "last_error:text", "run_at:datetime", "locked_at:datetime", "failed_at:datetime", "locked_by:string") Where would I put (or, rather, what is the syntax to add) the :default values in that? And if I wanted to add an index, what's the best way to do that?

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  • How do I connect to SQL Server with VB?

    - by Wayne Werner
    Hi, I'm trying to connect to a SQL server from VB. The SQL server is across the network uses my windows login for authentication. I can access the server using the following python code: import odbc conn = odbc.odbc('SignInspection') c = conn.cursor() c.execute("SELECT * FROM list_domain") c.fetchone() This code works fine, returning the first result of the SELECT. However, I've been trying to use the SqlClient.SqlConnection in VB, and it fails to connect. I've tried several different connection strings but this is the current code: Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim conn As New SqlClient.SqlConnection conn.ConnectionString = "data source=signinspection;initial catalog=signinspection;integrated security=SSPI" Try conn.Open() MessageBox.Show("Sweet Success") 'Insert some code here, woo Catch ex As Exception MessageBox.Show("Failed to connect to data source.") MessageBox.Show(ex.ToString()) Finally conn.Close() End Try End Sub It fails miserably, and it gives me an error that says "A network-related or instance-specific error occurred... (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) I'm fairly certain it's my connection string, but nothing I've found has given me any solid examples (server=mySQLServer is not a solid example) of what I need to use. Thanks! -Wayne

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  • Building a wiki like data model in rails question.

    - by lillq
    I have a data model in which I would like to have an item that has a description that can be edited. I would like to also keep track of all edits to the item. I am running into issues with my current strategy, which is: class Item < ActiveRecord::Base has_one :current_edit, :class_name => "Edit", :foreign_key => "current_edit_id" has_many :edits end class Edit < ActiveRecord::Base belongs_to :item end Can the Item have multiple associations to the same class like this? I was thinking that I should switch to keeping track of the edit version in the Edit object and then just sorting the has_many relationship base on this version.

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  • MS Access CrossTab query - across 3 tables

    - by Prembo
    Hi, I have the following 3 tables: 1) Sweetness Table FruitIndex CountryIndex Sweetness 1 1 10 1 2 20 1 3 400 2 1 50 2 2 123 2 3 1 3 1 49 3 2 40 3 3 2 2) Fruit Name Table FruitIndex FruitName 1 Apple 2 Orange 3 Peaches 3) Country Name Table CountryIndex CountryName 1 UnitedStates 2 Canada 3 Mexico I'm trying to perform a CrossTab SQL query to end up with: Fruit\Country UnitedStates Canada Mexico Apple 10 20 400 Orange 50 123 1 Peaches 49 40 2 The challenging part is to label the rows/columns with the relevant names from the Name tables. I can use MS Access to design 2 queries, create the joins the fruit/country names table with the Sweetness table perform crosstab query However I'm having trouble doing this in a single query. I've attempted nesting the 1st query's SQL into the 2nd, but it doesn't seem to work. Unfortunately, my solution needs to be be wholly SQL, as it is an embedded SQL query (cannot rely on query designer in MS Access, etc.). Any help greatly appreciated. Prembo.

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  • Django: Serializing models in a nested data structure?

    - by Rosarch
    It's easy to serialize models in an iterable: def _toJSON(models): return serializers.serialize("json", models, ensure_ascii=False) What about when I have something more complicated: [ (Model_A_1, [Model_B_1, Model_B_2, Model_B_3]), (Model_A_2, [Model_B_3, Model_B_4, Model_B_5, Model_B_59]), (Model_A_3, [Model_B_6, Model_B_7]), ] I tried serializing each model as it was added to the structure, then serializing the whole thing with simplejson.dumps, but that causes the JSON defining each model to be escaped. Is there a better way to do this?

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  • Syntax for "RETURNING" clause in Mysql PDO

    - by dmontain
    I'm trying to add a record, and at the same time return the id of that record added. I read it's possible to do it with a RETURNING clause. $stmt->prepare("INSERT INTO tablename (field1, field2) VALUES (:value1, :value2) RETURNING id"); but the insertion fails when I add RETURNING. There is an auto-incremented field called id in the table being added to. Can someone see anything wrong with my syntax? or maybe PDO does not support RETURNING?

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  • Oracle join query

    - by Jasim
    There are three tables in my db ITEM_MASTER, PRICE_MASTER, COMP_MASTER ITEM_MASTER STORE_CODE ITEM_CODE ITEM_DESC 011 914004 desccc PRICE_MASTER STORE_CODE ITEM_CODE COMP_CODE 011 914004 01 011 914004 02 011 914004 03 011 914004 04 COMP_MASTER COMP_CODE COMP_DESC STORE_CODE 01 comp1 011 02 comp2 011 03 comp3 011 04 comp4 011 I want to get all these for an ITEM_CODE in single query STORE_CODE ITEM_CODE ITEM_DESC COMP_DESC1 COMP_DESC2 COMP_DESC3 COMP_DESC4 011 914004 desccc comp1 comp2 comp3 comp4 How can i write a oracle SQL query for this??

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  • NoSQL for filesystem storage organization and replication?

    - by wheaties
    We've been discussing design of a data warehouse strategy within our group for meeting testing, reproducibility, and data syncing requirements. One of the suggested ideas is to adapt a NoSQL approach using an existing tool rather than try to re-implement a whole lot of the same on a file system. I don't know if a NoSQL approach is even the best approach to what we're trying to accomplish but perhaps if I describe what we need/want you all can help. Most of our files are large, 50+ Gig in size, held in a proprietary, third-party format. We need to be able to access each file by a name/date/source/time/artifact combination. Essentially a key-value pair style look-up. When we query for a file, we don't want to have to load all of it into memory. They're really too large and would swamp our server. We want to be able to somehow get a reference to the file and then use a proprietary, third-party API to ingest portions of it. We want to easily add, remove, and export files from storage. We'd like to set up automatic file replication between two servers (we can write a script for this.) That is, sync the contents of one server with another. We don't need a distributed system where it only appears as if we have one server. We'd like complete replication. We also have other smaller files that have a tree type relationship with the Big files. One file's content will point to the next and so on, and so on. It's not a "spoked wheel," it's a full blown tree. We'd prefer a Python, C or C++ API to work with a system like this but most of us are experienced with a variety of languages. We don't mind as long as it works, gets the job done, and saves us time. What you think? Is there something out there like this?

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  • How to get count of another table in a left join

    - by Sinan
    I have multiple tables post id Name 1 post-name1 2 post-name2 user id username 1 user1 2 user2 post_user post_id user_id 1 1 2 1 post_comments post_id comment_id 1 1 1 2 1 3 I am using a query like this: SELECT post.id, post.title, user.id AS uid, username FROM `post` LEFT JOIN post_user ON post.id = post_user.post_id LEFT JOIN user ON user.id = post_user.user_id ORDER BY post_date DESC It works as intended. However I would like the get the number of comments for each post too. So how can i modify the this query so I can get the count of comments. Any ideas?

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  • Doctrine: Relating a model to itself using a link table, like "This event is related to to the following other events"

    - by mattalexx
    So in English, the relationship would sound like "This event is related to to the following other events". My first instinct is to create an EventEvent model, with a first_event_id field and a second_event_id field. Then I would define the following two relationships in the Event model: $this->hasMany('Event as FirstRelatedEvents', array('local' => 'first_event_id', 'foreign' => 'second_event_id', 'refClass' => 'EventEvent')); $this->hasMany('Event as SecondRelatedEvents', array('local' => 'second_event_id', 'foreign' => 'first_event_id', 'refClass' => 'EventEvent')); But I would rather not have to use two relationships on the Event model. Is there a better way to do this?

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  • NHibernate, each property is filled with a different select statement

    - by Eitan
    I'm retrieving a list of nhibernate entites which have relationships to other tables/entities. I've noticed instead of NHibernate performing JOINS and populating the properties, it retrieves the entity and then calls a select for each property. For example if a user can have many roles and I retrieve a user from the DB, Nhibernate retrieves the user and then populates the roles with another select statement. The problem is that I want to retrieve oh let's say a list of products which have various many-to-many relationships and relationships to items which have their own relationships. In the end I'm left with over a thousand DB calls to retrieve a list of 30 products. Thanks. I've also set default lazy loading to false because whenever I save the list of entities to a session, I get an error when trying to retrieve it on another page: LazyInitializationException: could not initialize proxy If anybody could shed any light I would truly appreciate it. Thanks. Eitan

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  • ResultSet and aggregation

    - by kachanov
    Ok, I admit my situation is special There is a data system that supports SQL-92 and JDBC interface However the SQL requets are pretty expensive, and in my application I need to retreive the same data multiple times and aggregate it ("group by") on different fields to show different dimensions of the same data. For example on one screen I have three tables that show the same set or records but aggregated by City (1st grid), by Population (2nd grid), by number of babies (3rd grid) This amounts to 3 SQL queries (which is very slow), UNLESS anyone of you can suggest any idea any library from apache commons or from google code, so that I can select all records into ResultSet and get 3 arrays of data group by different fields from this single ResultSet. Am I'm missing some obvious and unexpected solution to this problem?

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  • SQLite - ON DUPLICATE KEY UPDATE

    - by Alix Axel
    MySQL has something like this: INSERT INTO visits (ip, hits) VALUES ('127.0.0.1', 1) ON DUPLICATE KEY UPDATE hits = hits + 1; As far as I'm know this feature doesn't exist in SQLite, what I want to know is if there is any way to archive the same effect without having to execute two queries. Also, if this is not possible, what do you prefer: SELECT + (INSERT or UPDATE) or UPDATE (+ INSERT if UPDATE fails)

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  • Select distinct users with referrals

    - by Mark
    I have a bunch of Users. Since Django doesn't really let me extend the default User model, they each have Profiles. The Profiles have a referred_by field (a FK to User). I'm trying to get a list of Users with = 1 referral. Here's what I've got so far Profile.objects.filter(referred_by__isnull=False).values_list('referred_by', flat=True) Which gives me a list of IDs of the users who have referrals... but I need it to be distinct, and I want the User object, not their ID. Or better yet, it would be nice if it could return the number of referrals a user has. Any ideas?

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