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  • Fetch last item in a category that fits specific criteria

    - by Franz
    Let's assume I have a database with two tables: categories and articles. Every article belongs to a category. Now, let's assume I want to fetch the latest article of each category that fits a specific criteria (read: the article does). If it weren't for that extra criteria, I could just add a column called last_article_id or something similar to the categories table - even though that wouldn't be properly normalized. How can I do this though? I assume there's something using GROUP BY and HAVING?

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  • Extreamely fast way to clone the values of an array into a second array?

    - by George
    I am currently working on an application that is responsible for calculating random permutations of a multidemensional array. Currently the bulk of the time in the application is spent copying the array in each iteration (1 million iterations total). On my current system, the entire process takes 50 seconds to complete, 39 of those seconds spent cloning the array. My array cloning routine is the following: public static int[][] CopyArray(this int[][] source) { int[][] destination = new int[source.Length][]; // For each Row for (int y = 0; y < source.Length; y++) { // Initialize Array destination[y] = new int[source[y].Length]; // For each Column for (int x = 0; x < destination[y].Length; x++) { destination[y][x] = source[y][x]; } } return destination; } Is there any way, safe or unsafe, to achieve the same effect as above, much faster?

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  • How to insert a value based on lookup from another table [SQL]?

    - by Shaitan00
    I need to find a way to do an INSERT INTO table A but one of the values is something that comes from a lookup on table B, allow me to illustrate. I have the 2 following tables: Table A: A1: String A2: Integer value coming from table B A3: More Data Table B: B1: String B2: Integer Value Example row of A: {"Value", 101, MoreData} Example row of B: {"English", 101} Now, I know I need to INSERT the following into A {"Value2", "English", MoreData} but obviously that won't work because it is expecting an Integer in the second column not the word "English", so I need to do a lookup in Table B first. Something like this: INSERT INTO tableA (A1, A2, A3) VALUES ("Value2", SELECT B2 FROM tableB where B1="English", MoreData); Obviously this doesn't work as-is ... Any suggestions?

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  • select columns by a concat text as columnname in oracle

    - by glaudiston
    I have a table with columns named with the number of hour of day like this: col00 NUMBER(5) col01 NUMBER(5) col02 NUMBER(5) ... col23 NUMBER(5) ...and I have another query that returns a count by hour. I want to recover the colXX value by hour.... then I can recover with "decode" or "case when..." but I want know if exists any way to recover the column by a text like this: select "col"||hour from table; in the hypothetical above example if hour is 13 then would be translated like: select col13 from table; there is any way to do this ?

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  • Changing newid() to newsequentialid() on an existing table

    - by cbp
    Hi, At the moment we have a number of tables that are using newid() on the primary key. This is causing large amounts of fragmentation. So I would like to change the column to use newsequentialid() instead. I imagine that the existing data will remain quite fragmented but the new data will be less fragmented. This would imply that I should perhaps wait some time before changing the PK index from non-clustered to clustered. My question is, does anyone have experience doing this? Is there anything I have overlooked that I should be careful of?

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  • Reading variable with double float precision from a text file with gnuplot

    - by user3636322
    I have a text file, containing data in 3 columns like below: 0.0100000000 | 0.0058077299 | -0.0000000288 0.0110000000 | 0.0075128707 | -0.0000000373 0.0120000000 | 0.0093579693 | -0.0000000465 I want to get the variables from this file in gnuplot and use them to draw graphs: What I exactly do is like below (e.g: to pick the variable from row 2 column 3): ii= 2 a_0 = system("awk '{ if (NR == " . ii . ") printf \"%f\", $3}' " .datafile) a_0 = a_0+0. but what is written as a_0 is zero! How can I increase the precision to get the exact value?

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  • building website with menu without using frames

    - by kms333
    With Dreamweaver, I use frames to define a left column menu, and clicking on each menu tab would change the html page displayed on the right frame. However, webdesign tools such as kompozer do not support frames. 1 - What is the best way to design a html personal webpage with such menu bars, without using frames ? 2 - If html is not enough, what other scripting languages would you recommend to learn for someone with Java background and have basic knowledge of html and css. 3 - What web-design tools would you recommend to build a personal website ?

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  • if specific row = null, execute query

    - by fusion
    how do i check if the value of a column is null, and only then execute the query? for example: col1 col2 col3 01 abc i run a query which first checks if the record exists or not; if it exists, it should execute the update query and if it doesn't exist, it executes the insert query. how do i check if col3 is null and if it is null, it should execute the update query. . $sql = "SELECT uid FROM `users` WHERE uid = '" . $user_id . "'"; $result = mysql_query($sql,$conn) or die('Error:' .mysql_error()); $totalrows = mysql_num_rows($result); if($totalrows < 1) { insertUser($user_id,$sk, $conn); } else { updateSessionKey($user_id,$sk,$conn); }

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  • Create Directory, 'cd' to it and download a file pipeline in Perl

    - by neversaint
    I have a file that looks like this: ftp://url1/files1.tar.gz dir1 ftp://url2/files2.txt dir2 .... many more... What I want to do are these steps: Create directory based on column 2 Unix 'cd' to that directory Download file with 'wget' based on column1 But how come this approach of mine doesn't work while(<>) { chomp; my ($url,$dir) = split(/\t/,$_); system("mkdir $dir"); system("cd $dir"); # Fail here system("wget $url"); # here too } What's the right way to do it?

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  • ValueError: setting an array element with a sequence.

    - by MedicalMath
    This code: import numpy as p def firstfunction(): UnFilteredDuringExSummaryOfMeansArray = [] MeanOutputHeader=['TestID','ConditionName','FilterType','RRMean','HRMean','dZdtMaxVoltageMean','BZMean','ZXMean' ,'LVETMean','Z0Mean','StrokeVolumeMean','CardiacOutputMean','VelocityIndexMean'] dataMatrix = BeatByBeatMatrixOfMatrices[column] roughTrimmedMatrix = p.array(dataMatrix[1:,1:17]) trimmedMatrix = p.array(roughTrimmedMatrix,dtype=p.float64) myMeans = p.mean(trimmedMatrix,axis=0,dtype=p.float64) conditionMeansArray = [TestID,testCondition,'UnfilteredBefore',myMeans[3], myMeans[4], myMeans[6], myMeans[9] , myMeans[10], myMeans[11], myMeans[12], myMeans[13], myMeans[14], myMeans[15]] UnFilteredDuringExSummaryOfMeansArray.append(conditionMeansArray) secondfunction(UnFilteredDuringExSummaryOfMeansArray) return def secondfunction(UnFilteredDuringExSummaryOfMeansArray): RRDuringArray = p.array(UnFilteredDuringExSummaryOfMeansArray,dtype=p.float64)[1:,3] return firstfunction() Throws this error message: File "mypath\mypythonscript.py", line 3484, in secondfunction RRDuringArray = p.array(UnFilteredDuringExSummaryOfMeansArray,dtype=p.float64)[1:,3] ValueError: setting an array element with a sequence. However, this code works: import numpy as p a=range(24) b = p.reshape(a,(6,4)) c=p.array(b,dtype=p.float64)[:,2] I re-arranged the code a bit to put it into a cogent posting, but it should more or less have the same result. Can anyone show me what to do to fix the problem in the broken code above so that it stops throwing an error message?

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  • Return cell reference as result of if statement with vlookups.

    - by EMJ
    I have two sets of data in excel. One contains a set of data which represents the initial step of a process. The other set of data represents the additional steps which take place after the first step is completed. Each of the data records in the "additional step data" has an id in a column. I need to find the identifying codes of the "additional step data" which correspond with the initial step data records. The problem is that I have to match the data in 4 columns between the two data sets and return the id of the "additional step data". I started by doing a combination of an if and vlookup functions, but I got stuck when I tried to figure out how to get the if statement to reference the id of the matching "additional step data". Basically I am trying to avoid having to search by manually filtering between two sets of data and finding corresponding records. Does anyone have any idea about how to do this?

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  • Rails create_table query

    - by Steve
    Hi, I am a beginner in Rails. In the following code,there is an id which is set as false. What's the meaning of it? class CreateCoursesStudents < ActiveRecord::Migration def self.up create_table :courses_students, :id => false do |t| t.integer :course_id, :null => false t.integer :student_id, :null => false end # Add index to speed up looking up the connection, and ensure # we only enrol a student into each course once add_index :courses_students, [:course_id, :student_id], :unique => true end def self.down remove_index :courses_students, :column => [:course_id, :student_id] drop_table :courses_students end end Thanks

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  • Unique number identifier generation

    - by xwrs
    I have to create logic for generation unique number identifier for records in database. id, generated in database is a separate column. At this moment, when user calls "create record" action, I save new record, get its database id, generate record number using this id, then put it to the edit form. Using this way means that all entity fields should be nullable to save record to database. I don't like this way. I know that should be better way. Is there a better practice to generate unique number identifier? What is possibility of generating non-unique random numbers? Thank you

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  • Serialized object in intent returning as String

    - by B_
    In my application, I am trying to pass a serializable object through an intent to another activity. The intent is not entirely created by me, it is created and passed through a search suggestion. In the content provider for the search suggestion, the object is created and placed in the SUGGEST_COLUMN_INTENT_EXTRA_DATA column of the MatrixCursor. However, when in the receiving activity I call getIntent().getSerializableExtra(SearchManager.EXTRA_DATA_KEY), the returned object is of type String and I cannot cast it into the original object class. I tried making a parcelable wrapper for my object that calls out.writeSerializable(...) and use that instead but the same thing happened. The string that is returned is like a generic Object toString(), i.e. com.foo.yak.MyAwesomeClass@4350058, so I'm assuming that toString() is being called somewhere where I have no control. Hopefully I'm just missing something simple. Thanks for the help!

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  • phpMyAdmin "No database selected" MySQL

    - by user1751660
    I downloaded a MySQL backup file and promptly imported into MAMP's phpMyAdmin. I got this return: Error SQL query: -- -- Database: `mysql` -- -- -------------------------------------------------------- -- -- Table structure for table `columns_priv` -- CREATE TABLE IF NOT EXISTS `columns_priv` ( `Host` CHAR( 60 ) COLLATE utf8_bin NOT NULL DEFAULT '', `Db` CHAR( 64 ) COLLATE utf8_bin NOT NULL DEFAULT '', `User` CHAR( 16 ) COLLATE utf8_bin NOT NULL DEFAULT '', `Table_name` CHAR( 64 ) COLLATE utf8_bin NOT NULL DEFAULT '', `Column_name` CHAR( 64 ) COLLATE utf8_bin NOT NULL DEFAULT '', `Timestamp` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP , `Column_priv` SET( 'Select', 'Insert', 'Update', 'References' ) CHARACTER SET utf8 NOT NULL DEFAULT '', PRIMARY KEY ( `Host` , `Db` , `User` , `Table_name` , `Column_name` ) ) ENGINE = MYISAM DEFAULT CHARSET = utf8 COLLATE = utf8_bin COMMENT = 'Column privileges'; MySQL said: #1046 - No database selected I did not alter the .sql file at all. Any hints on how i can get this puppy going locally? Thanks!

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  • Dynamic SQL Rows & Columns...cells require subsequent query. Best approach?

    - by Pyrrhonist
    I have the following tables below City --------- CityID StateID Name Description Reports --------- ReportID HeaderID FooterID Description I’m trying to generate a grid for use in a .Net control (Gridview, Listview…separate issue about which will be the ‘best’ one to use for my purposes) which will assign the reports as the columns and the cities as the rows. Which cities get displayed is based on the state selected, and is easy enough SELECT * FROM CITIES WHERE STATEID=@StateID However, the user is able to select which reports are being generated for each City (Demographics, Sales, Land Area, etc.). Further, the resultant cells (City * Report) is a sub-query on different tables based on the city selected and the report. Ie. Column Sales selected yields SELECT * FROM SALES WHERE CITYID=@CityID I’ve programmed a VERY inelegant solution using multiple queries and brute-forcing the grid to be created (line by line, row by row creation of data elements), but I’m positive there’s got to be a better way of accomplishing this…? Any / all suggestions appreciated here as the brute force approach I’ve gotten is slow and cumbersome…and this will have to be used often by the client, so I’m not sure it’ll be acceptable in it’s current implementation.

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  • How can I loop through each of the days of a given week in Ruby?

    - by Angela
    I am defining monday and friday using the following: @monday = Date.today.at_beginning_of_week @friday = 5.days.since(@monday) But I actually need, for any given day, to loop through Monday, Tuesday, Wednesday and take that date and put the output into a column. <th>Monday</th> <th>Tuesday</th> etcetera A given row, for example, would be: <tr><td>value(monday)</td><td>value(tuesday)</td><td>value(wednesday)</td></tr> This is where value is a method that takes args date. What's the cleanest way to do this? Thanks.

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  • Should I use a huge composite primary key or just a unique id?

    - by Jack
    I have been trying to do web scraping of a particular site and storing the results in a database. My original assumptions about the data allowed a schema where I could use fairly reasonable composite primary keys (usually containing only 2 or 3 fields) but as time went on, I realized that my original assumptions about the data were wrong and my primary keys were not as unique as I thought they were, so I have slowly been expanding them to contain more and more fields. In fact, I have recently come to believe that their database has no constraints whatsoever. Just today, I have finally expanded my a primary key for one of my tables to contain every field in that table and I thought now would be a good time to ask: is it better to add an auto-incrementing column that is just a unique id or just leave a composite primary key on the entire table?

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  • Activiti Engine: Task Event - User is null

    - by sockeqwe
    I have a problem, which should be simple to solve, but i can't find the method to call to solve this problem: My problem is, that every Task Event (org.activiti.engine.task.Event) returnes null by calling Event.getUserId(); If I take a look into the database I see that the database table ACT_HI_COMMENT has null as value for the column USER_ID_ for every row. I generate these TaskEvents programmatically by calling (for example) processEngine.getTaskService().addComment(task.getId(), null, commentMessage); processEngine.getTaskService().addUserIdentityLink(task.getId(), user.getId(), IDENTITY_LINK_OBSERVER); I guess there is a simple method that I must call to solve this problem, something like processEngine.setCurrentUser(authenticatedUser.getId()); Any suggestions?

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  • Adding index key in Grails' Domain

    - by firnnauriel
    I tried following this reference and this is now my domain's code: class SnbrActVector { long nid String term double weight static mapping = { version false nid index:'Nid_Idx' } static constraints = { term(blank:false) } } What I want is to do is to add an index key for 'nid' column. I dropped the existing table and run the app again so the table is then recreated. However, when i check for list of indices, I can't see a 'Nid_Idx', only available is 'PRIMARY'. Do I have to manually create the index and name it 'Nid_idx in my mysql database? Thanks.

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  • Ruby: totalling amounts

    - by Michael
    I have a Donation.rb model with an amount column that takes an integer. I want to sum all the individual donations together and show the total on the home page. In the home_controller, I'm doing @donations = Donation.all and then in the view I do <% sum = 0 %> <% @donations.each do |donation| %> <%= sum += donation.amount if donation.amount? %> <% end %> The problem is that this is printing the running sum each time a new donation is added to it. I just want the total sum at the end after they've all been added together.

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  • SSAS Reporting Services - Set specific language / translation

    - by Chris
    Hi all, in the data warehouse there's a default language for the measures, and I added a translation for German captions. In a Visual Studio Report Server project, when creating a query with my German OS, the cube and its measures are displayed in German language. When dragging measures to the mdx query windows, the default measure name is used. That's what I want and what I expect, since when writing MDX queries I would like to use the default measure names. But when executing the query, the columns created for each measure is translated to German again. This resuls in having German columns names within my dataset, which I dont want. I'd like to have the english column names. I already tried to change the connection string to: Data Source=server;Initial Catalog=DataWarehouse;LocaleIdentifier=1033 But that doesn't help, I still see German translations. Anyone knows how to set a specific translation?

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  • Dynamic SQL queries in code possible?

    - by SeanD
    Instead of hard coding sql queries like Select * from users where user_id =220202 can these be made dynamic like Select * from $users where $user_id = $input. Reason i ask is when changes are needed to table/column names i can just update it in one place and don't have to ask developers to go line by line to find all references to update. It is very time consuming. And I do not like the idea of exposing database stuff in the code. My major concern is load time. Like with dynamic pages, the database has to fetch the page content, same way if queries are dynamic first system has to lookup the references then execute the queries, so does it impact load times? I am using codeignitor PHP. If it it possible then the next question is where to store all the references? In the app, in a file, in the DB, and how?

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  • Python Continue Loop

    - by Rob B.
    I am using the following code from this tutorial (http://jeriwieringa.com/blog/2012/11/04/beautiful-soup-tutorial-part-1/). from bs4 import BeautifulSoup soup = BeautifulSoup (open("43rd-congress.html")) final_link = soup.p.a final_link.decompose() trs = soup.find_all('tr') for tr in trs: for link in tr.find_all('a'): fulllink = link.get ('href') print fulllink #print in terminal to verify results tds = tr.find_all("td") try: #we are using "try" because the table is not well formatted. This allows the program to continue after encountering an error. names = str(tds[0].get_text()) # This structure isolate the item by its column in the table and converts it into a string. years = str(tds[1].get_text()) positions = str(tds[2].get_text()) parties = str(tds[3].get_text()) states = str(tds[4].get_text()) congress = tds[5].get_text() except: print "bad tr string" continue #This tells the computer to move on to the next item after it encounters an error print names, years, positions, parties, states, congress However, I get an error saying that 'continue' is not properly in the loop on line 27. I am using notepad++ and windows powershell. How do I make this code work?

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  • ExtJS panel does not render properly unless I open Firebug - WTF?

    - by Huuuze
    I have the following ExtJS Panel embedded in another Panel, which then resides in a TabPanel and the TabPanel is in a FormPanel. With that being said, these start/end date fields are initially displayed in very small cells -- the cells are so small that I see horizontal scroll bars. Now here's the weird part: if I open Firebug, everything pops into place. Does anyone know what's going on? Why isn't it rendering properly in the first place and why does Firebug cause everything to work properly simply by opening Firebug? var dateFields = new Ext.Panel({ id: 'dateFields', labelAlign: 'bottom', border: false, items: [{ layout: 'column', defaults: { columnWidth: 0.5 }, items: [{ layout: 'form', border: false, items: [{ xtype: 'datefield', name: 'start_date', fieldLabel: 'Start Date' }] }, { layout: 'form', border: false, items: [{ xtype: 'datefield', name: 'end_date', fieldLabel: 'End Date' }] }] }] });

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