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  • how to convert legacy query to ActiveRecord Rails way

    - by josh
    I have a query in my code as below @sqladdpayment = "INSERT INTO payments (orderid, ttlprodcost, paytype, paystatus,created_at,updated_at,userid,storeid) VALUES ('" + session[:ordersid] + "', '" + session[:totalcost] + "', '" + "1"+ "', '" + "complete" +"',current_date, current_date, '"+"1"+"','"+ "1"+"')" Here the table payments and primary key is orderid. Now, I know if I convert this to the ActiveRecord way then I will not have to put update_date, current_date because it will put that on it's own. It will also put orderid on it's own also (auto_increment). I am looking for a way to convert the above query to ActiveRecord Rails way but still be able to put orderid on my own (session[:ordersid]). I do not want to rely on auto_increment because then I will have to refactor lot of the other code. This might be a quick and dirty fix but I want to know whether this type of flexibility is offered in rails? I have wondered about this question many times. Why won't rails allow me to have that flexibility?

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  • SQL -- How is DISTINCT so fast without an index?

    - by Jonathan
    Hi, I have a database with a table called 'links' with 600 million rows in it in SQLite. There are 2 columns in the database - a "src" column and a "dest" column. At present there are no indices. There are a fair number of common values between src and dest, but also a fair number of duplicated rows. The first thing I'm trying to do is remove all the duplicate rows, and then perform some additional processing on the results, however I've been encountering some weird issues. Firstly, SELECT * FROM links WHERE src=434923 AND dest=5010182. Now this returns one result fairly quickly and then takes quite a long time to run as I assume it's performing a tablescan on the rest of the 600m rows. However, if I do SELECT DISTINCT * FROM links, then it immediately starts returning rows really quickly. The question is: how is this possible?? Surely for each row, the row must be compared against all of the other rows in the table, but this would require a tablescan of the remaining rows in the table which SHOULD takes ages! Any ideas why SELECT DISTINCT is so much quicker than a standard SELECT?

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  • [C++] Is it possible to roll a significantly faster version of sqrt

    - by John
    In an app I'm profiling, I found that in some scenarios this functions are able to take over 10% of total execution time. I've seen discussion over the years of faster sqrt implementations using sneaky floating-point trickery, but I don't know if such things are outdated on modern CPUs. MSVC++ 2008 compiler is being used, for reference... though I'd assume sqrt is not going to add much overhead though.

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  • Split query result by half in TSQL (obtain 2 resultsets/tables)

    - by rubdottocom
    I have a query that returns a large number of heavy rows. When I transform this rows in a list of CustomObject I have a big memory peak, and this transformation is made by a custom dotnet framework that I can't modify. I need to retrieve a less number of rows to do "the transform" in two passes and then avoid the momery peak. How can I split the result of a query by half? I need to do it in DB layer. I thing to do a "Top count(*)/2" but how to get the other half? Thank you!

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  • If statement in MySQL query with PHP

    - by user1104854
    Is it possible to use an if statement in a MySQL query in a similar what I'm showing? I want to grab some information for upcoming events(not ones with previous dates). ini_set('date.timezone', 'America/New_York'); $timestamp = date('m/d/Y'); $sql = "select eventID,eventTitle,eventDate from events where eventLocationID = $locationID ORDER BY eventDate DESC IF(eventDate > $timestamp) "; I really want to avoid doing post-query if statements that will only print if it's after today's date because I run it through a pagination function, and I'd really prefer to avoid tinkering with that.

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  • Help in optimizing a for loop in matlab

    - by HH
    I have a 1 by N double array consisting of 1 and 0. I would like to map all the 1 to symbol '-3' and '3' and all the 0 to symbol '-1' and '1' equally. Below is my code. As my array is approx 1 by 8 million, it is taking a very long time. How to speed things up? [row,ll] = size(Data); sym_zero = -1; sym_one = -3; for loop = 1 : row if Data(loop,1) == 0 Data2(loop,1) = sym_zero; if sym_zero == -1 sym_zero = 1; else sym_zero = -1; end else Data2(loop,1) = sym_one; if sym_one == -3 sym_zero = 3; else sym_zero = -3; end end end

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  • serving cached files based upon cookie?

    - by matthewsteiner
    So I realized something today. In my application, you really can't get anywhere (except the front page) unless you're logged in. And you can't be logged in without a cookie. So my front page could be cached, except the problem is if you are logged in (have a cookie set) then it should just redirect into the application. Is there a way for nginx to look for a cookie and if it finds it then deliver a cached file? Just an idea...

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  • Is there a way to optimise finding text items on a page (not regex)

    - by Jeepstone
    After seeing several threads rubbishing the regexp method of finding a term to match within an HTML document, I've used the Simple HTML DOM PHP parser (http://simplehtmldom.sourceforge.net/) to get the bits of text I'm after, but I want to know if my code is optimal. It feels like I'm looping too many times. Is there a way to optimise the following loop? //Get the HTML and look at the text nodes $html = str_get_html($buffer); //First we match the <body> tag as we don't want to change the <head> items foreach($html->find('body') as $body) { //Then we get the text nodes, rather than any HTML foreach($body->find('text') as $text) { //Then we match each term foreach ($terms as $term) { //Match to the terms within the text nodes $text->outertext = str_replace($term, '<span class="highlight">'.$term.'</span>', $text->outertext); } } } For example, would it make a difference to determine check if I have any matches before I start the loop maybe?

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  • update query not working in array

    - by Suresh PHP Begginer
    here my code: i want to update the field by array. i just fetch the data's from table then i want to update the the field for same table // select query to get the value for($j=0;$j<count($capacity);$j++) { $capaci=$capacity[$j]; // select query to get the value $sql2=mysql_query("SELECT recieved-allocate*plate_quantity as ans from total_values where capacity='$capaci'"); while($fetch=mysql_fetch_array($sql2)) { $recieves=$fetch['ans']; $sql3="update total_values set recieved='$recieves' where capacity='$capaci' and month='$mon'"; mysql_query($sql3); } }

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  • Getting confused why i dont get expected amount ?

    - by Stackfan
    I have 1 result and which i will receive in Bank account, Based on that account i have to Put a balance to user account. How can you find the Handling cost from total tried 491.50 / 0.95 = 517.36 which is wrong ? It should be 500.00 (to my expectation) User balance requires 500.00 When 500.00 selected he gets 5% discount There is a handling cost for this ex: 1) Discount: 500.00 - 5% = 475.00 2) Handling cost: (475.00 x 0.034) + 0.35 = 16.50 3) Total: 475.00 + 16.50 = 491.50 So problem is from 491.50, i have to find atleast handling cost to get promised Balance. Any solution ? Cant figure it out myself...

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  • Best way to reverse a string in C# 2.0

    - by Guy
    I've just had to write a string reverse function in C# 2.0 (i.e. LINQ not available) and came up with this: public string Reverse(string text) { char[] cArray = text.ToCharArray(); string reverse = String.Empty; for (int i = cArray.Length - 1; i > -1; i--) { reverse += cArray[i]; } return reverse; } Personally I'm not crazy about the function and am convinced that there's a better way to do it. Is there?

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  • Can I do this in only one query ?

    - by Paté
    Merry christmas everyone, I Know my way around SQL but I'm having a hard time figuring this one out. First here are my tables (examples) User id name friend from //userid to //userid If user 1 is friend with user 10 then you a row with 1,10. User 1 cannot be friend with user 10 if user 10 is not friend with user 1 so you have 1,10 10,1 It may look weird but I need those two rows per relations. Now I'm trying to make a query to select the users that have the most mutual friend with a given user. For example User 1 is friend with user 10,9 and 7 and user 8 is friend with 10,9 and 7 too ,I want to suggest user 1 to invite him (like facebook). I want to get like the 10 first people with the most mutual friend. The output would be like User,NumOfMutualFriends I dont know if that can be done in a single query ? Thanks in advance for any help.

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  • Sql Server query performance

    - by Macros
    I have a stored procedure on a busy database which constantly come out top in the list of expensive queries (by some way). The query is very simple, it takes a single parameter (@ID, int) which is the primary key of the table, and selects the record that matches that ID. The primary key is an identity field with a clustered index, so I am stumped as to how to optimise this any further? The query is as follows CREATE PROCEDURE [dbo].[P_Call_Get] @ID int = null AS select ID, AppID, AgentID, AgentLogin, Ext, VDN, VDNName, Skill, SkillName, CallFrom, TelNoFrom, ParentCallID, CallStart, ACWStart, CallEnd, Outcome, StageID, TxTo, TxSuccess, ServiceID, DiallerID, CRC, TSCallID, CallDirection, [Manual], CallBackAgent, CallBackDateTime, Notes from P_Call where (ID = @ID or @ID is null) Not sure the best way to post the execution plan - all it shows is that 100% of the operation is taken up by the clustered index scan

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  • Filter Phrase Query

    - by alsuelo
    I try to filter a phrase to make a search in my website i've this query, this code working with one word but when i type wit more than one isn't working becuase the print is without spaces. $phrase = $this->getState($this->context.".filter_phrase"); printf("Original string: %s\n", $phrase); if(!empty($phrase)) { $escaped = $db->escape($phrase, true); printf("Escaped string: %s\n", $escaped); $quoted = $db->quote("%" . $escaped . "%" , false); $query->where ('a.title LIKE ' .$quoted); } Example i type king and the output is king , when i type the king the output is theking, i want to know if exist any way to conserve the blank spaces.

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  • Java API Method Run Times

    - by Mike
    Is there a good resource to get run times for standard API functions? It's somewhat confusing when trying to optimize your program. I know Java isn't made to be particularly speedy but I can't seem to find much info on this at all. Example Problem: If I am looking for a certain token in a file is it faster to scan each line using string.contains(...) or to bring in say 100 or so lines putting them to a local string them performing contains on that chunk.

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  • Query string problem if we use header

    - by avani-nature
    Hai frnds i am new to php actually i am facing following problems in coding please can anyone give the solution? Actually i am having one audio player and i am displaying some word dcoument if i click word document corresponding audio file should play actually when i click doc file it should pop ip with save as and open with for that i am using some header code also i am passing query string in the browser query string is not working if i use header can anyone give me a solution for it below is my code i am attaching <?php $f_name = $_POST["fn"]; $id = $_POST["id1"]; echo $id; //echo "../public_html/sites/default/files/ourfiles/$f_name"; $res2=db_query("select * from mt_files where id='".$id."' "); $row2=db_fetch_array($res2); $job_audio=$row2["audio_name"]; //echo $job_audio; //$job_audi=explode("/",$job_audio); //$job_audio=$job_audi[8]; $job_audio= "C:/xampp/htdocs/med/sites/default/files/audio/$job_audio"; //$job_audio= "C:/Documents and Settings/swuser/My Documents/$job_audio"; //echo $job_audio; echo "<object data='$job_audio' type='application/x-mplayer2' width='150' height='45'> <param name='src' value='$job_audio'> <param name='autoplay' value='true'> <param name='autoStart' value='1'> </object> "; $file = "../mts/sites/default/files/docs/$f_name"; if (file_exists($file)) { header('Content-Description: File Transfer'); header('Content-Type: application/octet-stream'); header('Content-Disposition: attachment; filename='.basename($file)); header('Content-Transfer-Encoding: binary'); header('Expires: 0'); header('Cache-Control: must-revalidate, post-check=0, pre-check=0'); header('Pragma: public'); header('Content-Length: ' . filesize($file)); ob_clean(); flush(); readfile($file); exit; } //The download table query goes here put the $f_name in insert into with the //time varible ?>

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  • Storing information in the DOM?

    - by John
    Im making a small private message application in the form of a phone. Ten messages are shown at the time. And the list of messages are scrolled up/down by hiding them. Just how bad is it to use the DOM to store information in this way. My main goal for doing this is to reduce calls to the database. And instead of making a new call all the time, it only checks if any new messages has arrived and ads the new message(s). Whats the alternative, cookies anyone? Thank you for the time

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  • Calling a method on an object a bunch of times versus constructing an object a bunch of times

    - by Ami
    I have a List called myData and I want to apply a particular method (someFunction) to every element in the List. Is calling a method through an object's constructor slower than calling the same method many times for one particular object instantiation? In other words, is this: for(int i = 0; i < myData.Count; i++) myClass someObject = new myClass(myData[i]); slower than this: myClass someObject = new myClass(); for(int i = 0; i < myData.Count; i++) someObject.someFunction(myData[i]); ? If so, how much slower?

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  • What is microbenchmarking?

    - by polygenelubricants
    I've heard this term used, but I'm not entirely sure what it means, so: What DOES it mean and what DOESN'T it mean? What are some examples of what IS and ISN'T microbenchmarking? What are the dangers of microbenchmarking and how do you avoid it? (or is it a good thing?)

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  • Index out of range exception when using this query from C#

    - by jenifa
    I am using a calculation in my SQL query. How can I use that calculated field in C#? When I try, I get an index out of range exception. My query is: Select OwnerCompanyLog.olog_name,inlt_companyid,inlt_childcompid,inlt_effectinterest,inlt_percent,inlt_sharetype,inlt_shares,inlt_childbase,inlt_effdate, (inlt_percent * inlt_effectinterest)/100)eff from InterestLogTable INNER JOIN OwnerCompanyLog ON InterestLogTable.inlt_childcompid = OwnerCompanyLog.olog_companyid where inlt_companyid=5 Order By inlt_childcompid I want to use inlt_percent * inlt_effectinterest)/100 in my C# code: entity.ParentCompany = new List<Company>(); while (parentCompanyReader.Read()) { ParentCompany.Effect = parentCompanyReader["eff"].ToString(); entity.ParentCompany.Add(ParentCompany); } parentCompanyReader.Close(); But I got the error above.

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  • [MySQL] Optimize Query

    - by bordeux
    Hello. I have problem with optimize this query: SET @SEARCH = "dokumentalne"; SELECT SQL_NO_CACHE `AA`.`version` AS `Version` , `AA`.`contents` AS `Contents` , `AA`.`idarticle` AS `AdressInSQL` , `AA` .`topic` AS `Topic` , MATCH (`AA`.`topic` , `AA`.`contents`) AGAINST (@SEARCH) AS `Relevance` , `IA`.`url` AS `URL` FROM `xv_article` AS `AA` INNER JOIN `xv_articleindex` AS `IA` ON ( `AA`.`idarticle` = `IA`.`adressinsql` ) INNER JOIN ( SELECT `idarticle` , MAX( `version` ) AS `version` FROM `xv_article` WHERE MATCH (`topic` , `contents`) AGAINST (@SEARCH) GROUP BY `idarticle` ) AS `MG` ON ( `AA`.`idarticle` = `MG`.`idarticle` ) WHERE `IA`.`accepted` = "yes" AND `AA`.`version` = `MG`.`version` ORDER BY `Relevance` DESC LIMIT 0 , 30 Now, this query using ^ 20 seconds. How to optimize this? EXPLAIN gives this: 1 PRIMARY AA ALL NULL NULL NULL NULL 11169 Using temporary; Using filesort 1 PRIMARY ALL NULL NULL NULL NULL 681 Using where 1 PRIMARY IA ALL accepted NULL NULL NULL 11967 Using where 2 DERIVED xv_article fulltext topic topic 0 1 Using where; Using temporary; Using filesort This is example server with my data: user: bordeux_4prog password: 4prog phpmyadmin: http://phpmyadmin.bordeux.net/ chive: http://chive.bordeux.net/

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  • Optimal (Time paradigm) solution to check variable within boundary

    - by kumar_m_kiran
    Hi All, Sorry if the question is very naive. I will have to check the below condition in my code 0 < x < y i.e code similar to if(x > 0 && x < y) The basic problem at system level is - currently, for every call (Telecom domain terminology), my existing code is hit (many times). So performance is very very critical, Now, I need to add a check for boundary checking (at many location - but different boundary comparison at each location). At very normal level of coding, the above comparison would look very naive without any issue. However, when added over my statistics module (which is dipped many times), performance will go down. So I would like to know the best possible way to handle the above scenario (kind of optimal way for limits checking technique). Like for example, if bit comparison works better than normal comparison or can both the comparison be evaluation in shorter time span? Other Info x is unsigned integer (which must be checked to be greater than 0 and less than y). y is unsigned integer. y is a non-const and varies for every comparison. Here time is the constraint compared to space. Language - C++. Now, later if I need to change the attribute of y to a float/double, would there be another way to optimize the check (i.e will the suggested optimal technique for integer become non-optimal solution when y is changed to float/double). Thanks in advance for any input. PS : OS used is SUSE 10 64 bit x64_64, AIX 5.3 64 bit, HP UX 11.1 A 64.

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