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  • Retrieve sequence of data from different columns.

    - by janetsmith
    Let's say I have a table containing following data: | id | t0 | t1 | t2 | | 1 | 4 | 5 | 6 | | 2 | 3 | 3 | 2 | | 3 | 6 | 4 | 5 | | 4 | 4 | 5 | 5 | I want to retrieve all the rows containing 4, 5, 6 (regardless the position of numbers in the tables), so row 1 & row 3 will be selected. How to do that with SQL query?

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  • What are best practices for collecting, maintaining and ensuring accuracy of a huge data set?

    - by Kyle West
    I am posing this question looking for practical advice on how to design a system. Sites like amazon.com and pandora have and maintain huge data sets to run their core business. For example, amazon (and every other major e-commerce site) has millions of products for sale, images of those products, pricing, specifications, etc. etc. etc. Ignoring the data coming in from 3rd party sellers and the user generated content all that "stuff" had to come from somewhere and is maintained by someone. It's also incredibly detailed and accurate. How? How do they do it? Is there just an army of data-entry clerks or have they devised systems to handle the grunt work? My company is in a similar situation. We maintain a huge (10-of-millions of records) catalog of automotive parts and the cars they fit. We've been at it for a while now and have come up with a number of programs and processes to keep our catalog growing and accurate; however, it seems like to grow the catalog to x items we need to grow the team to y. I need to figure some ways to increase the efficiency of the data team and hopefully I can learn from the work of others. Any suggestions are appreciated, more though would be links to content I could spend some serious time reading. THANKS! Kyle

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  • Tricky SQL query involving consecutive values

    - by Gabriel
    I need to perform a relatively easy to explain but (given my somewhat limited skills) hard to write SQL query. Assume we have a table similar to this one: exam_no | name | surname | result | date ---------+------+---------+--------+------------ 1 | John | Doe | PASS | 2012-01-01 1 | Ryan | Smith | FAIL | 2012-01-02 <-- 1 | Ann | Evans | PASS | 2012-01-03 1 | Mary | Lee | FAIL | 2012-01-04 ... | ... | ... | ... | ... 2 | John | Doe | FAIL | 2012-02-01 <-- 2 | Ryan | Smith | FAIL | 2012-02-02 2 | Ann | Evans | FAIL | 2012-02-03 2 | Mary | Lee | PASS | 2012-02-04 ... | ... | ... | ... | ... 3 | John | Doe | FAIL | 2012-03-01 3 | Ryan | Smith | FAIL | 2012-03-02 3 | Ann | Evans | PASS | 2012-03-03 3 | Mary | Lee | FAIL | 2012-03-04 <-- Note that exam_no and date aren't necessarily related as one might expect from the kind of example I chose. Now, the query that I need to do is as follows: From the latest exam (exam_no = 3) find all the students that have failed (John Doe, Ryan Smith and Mary Lee). For each of these students find the date of the first of the batch of consecutively failing exams. Another way to put it would be: for each of these students find the date of the first failing exam that comes after their last passing exam. (Look at the arrows in the table). The resulting table should be something like this: name | surname | date_since_failing ------+---------+-------------------- John | Doe | 2012-02-01 Ryan | Smith | 2012-01-02 Mary | Lee | 2012-01-04 Ann | Evans | 2012-02-03 How can I perform such a query? Thank you for your time.

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  • MySql, InnoDB & Null Values

    - by pws5068
    Formerly I was using MyISAM storage engine for MySql and I had defined the combination of three fields to be unique. Now I have switched to InnoDB, which I assume caused this problem, and now NULL != NULL. So for the following table: ID (Auto) | Field_A | Field_B | Field_C I can insert (Field_A,Field_B,Field_C) Values(1,2,NULL) (1,2,NULL) (1,2,NULL) infinitely many times. How can I prevent this behavior?

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  • How to implement Object Databases in Asp.net MVC(c#)

    - by amexn
    I started my project in Asp.net MVC(c#) & MSSQL 2005.I want to implement Object Databases in my project. While searched in google i found "MongoDb" I didn't have enough knowledge in Object Databases & which one best suited for MSSQL 2005. Please suggest a good example/reference regarding Object Databases implementation in Asp.net MVC application

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  • Oracle Trigger to persist value

    - by Jose Jose
    I have a column that I need to be able to guarantee never gets set to anything other than "N" - I thought a trigger would be the perfect solution for this, but I can't seem to figure out how to make it so that anytime the column gets set to something other than "N" I reset it back to "N" Any pointers? EDIT: I wouldn't want to do a constraint because the application that will potentially change it to Y is outside of my control and I don't want it to be getting errors when it sets it to Y, I just want to passively set it back to N without fanfare.

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  • can't use db:seed in rails

    - by Stacia
    I updated my rails gem to 2.3.5 but I keep getting this error when running db:seed: $ rake db:seed --trace (in c:/Documents and Settings/Owner/workspace/thepatstudio) rake aborted! Don't know how to build task 'db:seed' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1728:in `[]' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2050:in `invoke_task' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' c:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 c:/Ruby/bin/rake:19:in `load' c:/Ruby/bin/rake:19 ~/workspace/thepatstudio (master) $ rails --version Rails 2.3.5 My environment.rb has the correct rails version on it and I also ran rake rails:update. What can I do?

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  • Modifying SQL Server Schema Collection

    - by Mevdiven
    SQL Server XML Schema Collection is an interesting concept and I find it very useful when designing dynamic data content. However as I work my way through implementing Schema Collections, I find it very difficult to maintain them. Schema Collection DDL allows only CREATE and ALTER/ADD nodes to existing schemes. CREATE XML SCHEMA COLLECTION [ <relational_schema>. ]sql_identifier AS 'XSD Content' ALTER XML SCHEMA COLLECTION [ <relational_schema>. ]sql_identifier ADD 'Schema Component' When you want to remove any node from a schema you have to issue following DDL's. If that schema collection assigned to a table column, you have to alter table to remove schema collection association from that column Drop the schema collection object Re-Create schema collection Alter table column to re-associate schema collection to that column. This is pain when it comes to 100+ of schemes in a collection. Also you have to re-create XML indexes all over again, if any. Any solutions, suggestions, tricks to make this schema collection object editing process easier?

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  • Query that ignore the spaces.

    - by xRobot
    What's the best way to run a query so that spaces in the fields are ignored? For example the following queries.... SELECT * FROM mytable WHERE username = "JohnBobJones" SELECT * FROM mytable WHERE username = "John Bob Jones" . would find the following entries: John Bob Jones JohnBob Jones JohnBobJones . I am using php or python but I think this doesn't matter.

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  • Modify Wordpress SQL Query to pull from within a category

    - by Levi
    Hi I am using a wordpress plugin called "kf most read" which stores a count of how many times a post was read, and lets you output a list of most read posts. This works well. The issue is, I am trying to pull the most read posts, but only the most read posts within the current category you are viewing. I am close to clueless when it comes to sql. Here us what the plugin is currently using to pull the most read posts: $sql = "SELECT count(mr.post_ID) as totHits, p.ID, p.post_title from $wpdb-posts p JOIN {$wpdb-prefix}kf_most_read mr on mr.post_ID = p.ID where mr.hit_ts = '".(time() - ( 86400 * $period))."' GROUP BY mr.post_ID order by totHits desc, ID ASC LIMIT $limit"; How could I incorporate the below query which pulls from a specific category into the above? $sql .= "LEFT JOIN $wpdb-term_taxonomy ON($wpdb-term_relationships.term_taxonomy_id = $wpdb-term_taxonomy.term_taxonomy_id)" ; $sql .= "WHERE $wpdb-term_taxonomy.term_id IN ($currentcat)" ; $sql .= "AND $wpdb-term_taxonomy.taxonomy = 'category'" ; Any Help on this would be much appreciated.

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  • Starting out NLP - Python + large data set

    - by pencilNero
    Hi, I've been wanting to learn python and do some NLP, so have finally gotten round to starting. Downloaded the english wikipedia mirror for a nice chunky dataset to start on, and have been playing around a bit, at this stage just getting some of it into a sqlite db (havent worked with dbs in the past unfort). But I'm guessing sqlite is not the way to go for a full blown nlp project(/experiment :) - what would be the sort of things I should look at ? HBase (.. and hadoop) seem interesting, i guess i could run then im java, prototype in python and maybe migrate the really slow bits to java... alternatively just run Mysql.. but the dataset is 12gb, i wonder if that will be a problem? Also looked at lucene, but not sure how (other than breaking the wiki articles into chunks) i'd get that to work.. What comes to mind for a really flexible NLP platform (i dont really know at this stage WHAT i want to do.. just want to learn large scale lang analysis tbh) ? Many thanks.

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  • apostrophe in mysql/php

    - by fusion
    i'm trying to learn php/mysql. inserting data into mysql works fine but inserting those with apostrophe is generating an error. i tried using mysql_real_escape_string, yet this doesn't work. would appreciate any help. <?php include 'config.php'; echo "Connected <br />"; $auth = $_POST['author']; $quo = $_POST['quote']; $author = mysql_real_escape_string($auth); $quote = mysql_real_escape_string($quo); //************************** //inserting data $sql="INSERT INTO Quotes (vauthor, cquotes) VALUES ($author, $quote)"; if (!mysql_query($sql,$conn)) { die('Error: ' . mysql_error()); } echo "1 record added"; ... what am i doing wrong?

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  • Don't Understand Sql Server Error

    - by Jonathan Wood
    I have a table of users (User), and need to create a new table to track which users have referred other users. So, basically, I'm creating a many-to-many relation between rows in the same table. So I'm trying to create table UserReferrals with the columns UserId and UserReferredId. I made both columns a compound primary key. And both columns are foreign keys that link to User.UserID. Since deleting a user should also delete the relationship, I set both foreign keys to cascade deletes. When the user is deleted, any related rows in UserReferrals should also delete. But this gives me the message: 'User' table saved successfully 'UserReferrals' table Unable to create relationship 'FK_UserReferrals_User'. Introducing FOREIGN KEY constraint 'FK_UserReferrals_User' on table 'UserReferrals' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. See previous errors. I don't get this error. A cascading delete only deletes the row with the foreign key, right? So how can it cause "cycling cascade paths"? Thanks for any tips.

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  • Replication: SQL Server 2008 Publisher with SQL Server Express 2005 Subscriber

    - by Jeremy
    Here is the setup: SQL Server 2008 Enterprise Server with a Merge Publication. SQL Server 2005 Express with pull subscription. There is no web or ftp setup. This is direct merge replication. Using the RMO objects from C#, I get a "class cannot be found." COM Error when accessing the MergePullSubscription.SynchronizationAgent property. I've tried with both the 2008 RMO dll's (version 10 dll's) and the 2005 RMO dll's (version 9 dll's). When trying to use replmerge.exe, I get the following: 2010-04-10 04:12:05.263 Microsoft SQL Server Merge Agent 9.00.1399.06 2010-04-10 04:12:05.294 Copyright (c) 2000 Microsoft Corporation 2010-04-10 04:12:05.294 2010-04-10 04:12:05.294 The timestamps prepended to the output lines are express ed in terms of UTC time. 2010-04-10 04:12:05.294 User-specified agent parameter values: -Publisher SUN -PublisherDB PRIMROSE -PublisherSecurityMode 1 -Publication PRIMROSE -Distributor SUN -DistributorSecurityMode 1 -Subscriber PVILLE\SQLEXPRESS -SubscriberSecurityMode 1 -SubscriberDB PRIMROSE -SubscriptionType 1 -DistributorLogin sa -DistributorPassword ********** -DistributorSecurityMode 0 -PublisherLogin sa -PublisherPassword ********** -PublisherSecurityMode 0 -SubscriberLogin sa -SubscriberPassword ********** -SubscriberSecurityMode 0 2010-04-10 04:12:05.325 Connecting to Subscriber 'PVILLE\SQLEXPRESS' 2010-04-10 04:12:05.481 Connecting to Distributor 'SUN' 2010-04-10 04:12:05.513 The version of SQL Server running at the Distributor(10. 0.2531.??????????????????) is not compatible with the version of SQL Server runn ing at the Subscriber(9.00.1399.???????L?L?LHL?L?L?L?,?). 2010-04-10 04:12:05.513 Category:NULL Source: Merge Process Number: -2147200979 Message: The version of SQL Server running at the Distributor(10.0.2531.???????? ??????????) is not compatible with the version of SQL Server running at the Subs criber(9.00.1399.???????L?L?LHL?L?L?L?,?). Any ideas?

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  • Large scale storage for incrementally-appended documents?

    - by Ben Dilts
    I need to store hundreds of thousands (right now, potentially many millions) of documents that start out empty and are appended to frequently, but never updated otherwise or deleted. These documents are not interrelated in any way, and just need to be accessed by some unique ID. Read accesses are some subset of the document, which almost always starts midway through at some indexed location (e.g. "document #4324319, save #53 to the end"). These documents start very small, at several KB. They typically reach a final size around 500KB, but many reach 10MB or more. I'm currently using MySQL (InnoDB) to store these documents. Each of the incremental saves is just dumped into one big table with the document ID it belongs to, so reading part of a document looks like "select * from saves where document_id=14 and save_id 53 order by save_id", then manually concatenating it all together in code. Ideally, I'd like the storage solution to be easily horizontally scalable, with redundancy across servers (e.g. each document stored on at least 3 nodes) with easy recovery of crashed servers. I've looked at CouchDB and MongoDB as possible replacements for MySQL, but I'm not sure that either of them make a whole lot of sense for this particular application, though I'm open to being convinced. Any input on a good storage solution?

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  • Invoice & Invoice lines: How do you store customer address information?

    - by elviejo
    Hi I'm developing an invoicing application. So the general idea is to have two tables: Invoice (ID, Date, CustomerAddress, CustomerState, CustomerCountry, VAT, Total); InvoiceLine (Invoice_ID, ID, Concept, Units, PricePerUnit, Total); As you can see this basic design leads to a lot of repetiton of records where the client will have the same addrres, state and country. So the alternative is to have an address table and then make a relationship Address<-Invoice. However I think that an invoice is immutable document and should be stored just the way it was first made. Sometimes customers change their addresses, or states and if it was coming from an Address catalog that will change all the previously made invoices. So What is your experience? How is the customer address stored in an invoice? In the Invoice table? an Address Table? or something else? Can you provide pointers to a book, article or document where this is discussed in further detail?

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  • How to explain to users the advantages of dumb primary key?

    - by Hao
    Primary key attractiveness I have a boss(and also users) that wants primary key to be sophisticated/smart/attractive control number(sort of like Social Security number, or credit card number format) I just padded the primary key(in Views) with zeroes to appease their desire to make the control number sophisticated,smart and attractive. But they wanted it as: first 2 digits as client code, then 4 digits as year year, then last 4 digits as transaction number on that client on a given year, then reset the transaction number of client to 1 when next year flows. Each client's transaction starts with 1. e.g. WM20090001, WM20090002, BB2009001, WM20100001, BB20100001 But as I wanted to make things as simple as possible, I forgo embedding their suggested smartness in primary key, I just keep the primary key auto increments regardless of client and year. But to make it not dull-looking(they really are adamant to make the primary key as smart control number), I made the primary key appears to them smart, on view query, I put the client code and four digit year code on front of the eight-zero padded autoincrement key, i.e. WM200900000001. Sort of slug-like information on autoincremented primary key. Keeping primary key autoincrement regardless of any other information, we are able keep other potential side effects problem when they edit a record, for example, if they made a mistake of entering the transaction on WM, then they edit the client code to BB, if we use smart primary key, the primary keys of WM customer will have gaps in their control number. Or worse yet, instead of letting the control numbers have gaps/holes, the user will request that subsequent records of that gap should shift up to that gap and have their subsequent primary keys re-adjust(decremented). How do you deal with these user requests(reasonable or otherwise)? Do you yield to their request? Or just continue using dumb primary key and explain them the repercussions of having a very smart/sophisticated primary key and educate them the significant advantages of having a dumb primary key? P.S. quotable quote(http://articles.techrepublic.com.com/5100-10878_11-1044961.html): "If you hold your tongue the first time users ask what is for them a reasonable request, things will work a lot better in the end."

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  • Product table, many kinds of product, each product has many parameters

    - by StoneHeart
    Hi, i'm have not much experience in table design. My goal is a product table(s), it must design to fix some requirement below: Support many kind of products (TV, Phone, PC, ...). Each kind of product has different set of parameters like: Phone will have Color, Size, Weight, OS... PC will have CPU, HDD, RAM... Set of parameters must be dynamic. You can add or edit any parameter you like. I don't want make a table for each kind of product. So I need help to find a correct solution. Thanks.

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