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  • Error using to_char // to_timestamp

    - by pepersview
    Hello, I have a database in PostgreSQL and I'm developing an application in PHP using this database. The problem is that when I execute the following query I get a nice result in phpPgAdmin but in my PHP application I get an error. The query: SELECT t.t_name, t.t_firstname FROM teachers AS t WHERE t.id_teacher IN (SELECT id_teacher FROM teacher_course AS tcourse JOIN course_timetable AS coursetime ON tcourse.course = coursetime.course AND to_char(to_timestamp('2010-4-12', 'YYYY-MM-DD'),'FMD') = (coursetime.day +1)) AND t.id_teacher NOT IN (SELECT id_teacher FROM teachers_fill WHERE date = '2010-4-12') ORDER BY t.t_name ASC And this is the error in PHP operator does not exist: text = integer (to_timestamp('', 'YYYY-MM-DD'),'FMD') = (courset... ^ HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts. The purpose to solve this error is to use the ORIGINAL query in php with : $date = "2010"."-".$selected_month."-".$selected_day; SELECT t.t_name, t.t_firstname FROM teachers AS t WHERE t.id_teacher IN (SELECT id_teacher FROM teacher_course AS tcourse JOIN course_timetable AS coursetime ON tcourse.course = coursetime.course AND to_char(to_timestamp('$date', 'YYYY-MM-DD'),'FMD') = (coursetime.day +1)) AND t.id_teacher NOT IN (SELECT id_teacher FROM teachers_fill WHERE date = '$date') ORDER BY t.t_name ASC

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  • Login problem with php

    - by shinod
    I want to prevent multiple log in with same log in credentials simultaneously. So I made a column login_status and set it to 1 when some one logging in and change to 0 when logging out besides I set session after successful logged in. If user won't click on log out(in case of user close tab or because of some network problem) it doesn't update database and then one can't use that log in credentials again. So I use a ajax call to set current time stamp in database with related log in credentials and it is updated in each 2 minutes if user not navigate from that page. Then if some one attempts to log in with same log in credentials, it will check these time stamp if column login_status is 1, then if the time stamp is older than 3 minutes it allows the log in.Then it solving that problem. But the new problem is if user closes the tab or browser window and after 3 minutes one can log in with same log in credentials from somewhere and if the previous user open that page automatically it will log in as session is already set. How can I prevent this.

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  • Technology Plan - Which tools should I use?

    - by Armadillo
    Hi, Soon, I'll start my own software company. My primary product/solution will be a Billing/Invoice Software. In a near future, I pretend to expand this first module to an ERP. My app should be able to run as a stand-alone application and as a Web-based application (so there will be, probably two GUI for the same Database). My problem, now, is to choose the right tools; I'm talking about what programming language(s) should I use, what kind of database should I choose, and stuff like that. I'm primarily a VB6 programmer, so probably I'll choose the .net framework (vb/c#). But I'm seriously thinking about Java. Java has 2 "pros" that I really like: write once, run anywhere and it is free (I think...). I've been thinking about RIAs too, but I just don't have any substantial feedback about them... Then, I'll need a report tool. Crystal Reports? HTML based Reports? Other? Databases: I'm not sure if I should use SQL-Server Express or PostgreSQL (or other). I'd be happy to hear any comments and advices Thanks

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  • Is there a standard pattern for scanning a job table executing some actions?

    - by Howiecamp
    (I realize that my title is poor. If after reading the question you have an improvement in mind, please either edit it or tell me and I'll change it.) I have the relatively common scenario of a job table which has 1 row for some thing that needs to be done. For example, it could be a list of emails to be sent. The table looks something like this: ID Completed TimeCompleted anything else... ---- --------- ------------- ---------------- 1 No blabla 2 No blabla 3 Yes 01:04:22 ... I'm looking either for a standard practice/pattern (or code - C#/SQL Server preferred) for periodically "scanning" (I use the term "scanning" very loosely) this table, finding the not-completed items, doing the action and then marking them completed once done successfully. In addition to the basic process for accomplishing the above, I'm considering the following requirements: I'd like some means of "scaling linearly", e.g. running multiple "worker processes" simultaneously or threading or whatever. (Just a specific technical thought - I'm assuming that as a result of this requirement, I need some method of marking an item as "in progress" to avoid attempting the action multiple times.) Each item in the table should only be executed once. Some other thoughts: I'm not particularly concerned with the implementation being done in the database (e.g. in T-SQL or PL/SQL code) vs. some external program code (e.g. a standalone executable or some action triggered by a web page) which is executed against the database Whether the "doing the action" part is done synchronously or asynchronously is not something I'm considering as part of this question.

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  • Convert date to string upon saving a doctrine record

    - by takteek
    Hi, I'm trying to migrate one of my PHP projects to Doctrine. I've never used it before so there are a few things I don't understand. In my current code, I have a class similar to this: class ScheduleItem { private Date start; //A PEAR Date object. private Date end; public function getStart() { return $this-start; } public function setStart($val) { $this-start = $val; } public function getEnd() { return $this-end; } public function setEnd($val) { $this-end= $val; } } I have a ScheduleItemDAO class with methods like save(), getByID(), etc. When loading from and saving to the database, the DAO class converts the Date objects to and from strings so they can be stored in a timestamp field. In my attempt to move to Doctrine, I created a new class like this: class ScheduleItem extends Doctrine_Record { public function setTableDefinition() { $this-hasColumn('start', 'timestamp'); $this-hasColumn('end', 'timestamp'); } } I had hoped I would be able to use Date objects for the start and end times, and have them converted to strings when they are saved to the database. How can I accomplish this?

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  • MySQL PHP SELECT throwing up an error?

    - by user1909695
    I am trying to make a comment section on my hand made site, using PHP and MySQL. I have got the comments stored in my database, but when I try to SELECT them my site throws up this error, mysql_result() [function.mysql-result]: Unable to jump to row 0 on MySQL result index 9 in /home/a9210109/public_html/comments.php on line 16 My code so far is below <?php $comment = $_POST['comment']; $mysql_host = ""; $mysql_database = ""; $mysql_user = ""; $mysql_password = ""; mysql_connect($mysql_host,$mysql_user,$mysql_password); @mysql_select_db($mysql_database) or die( "Unable to select database"); $CreateTable = "CREATE TABLE comments (comment VARCHAR(255), time VARCHAR(255));"; mysql_query($CreateTable); $UseComment = "INSERT INTO comments VALUES ('$comment')"; mysql_query($UseComment); $SelectComments = "SELECT * FROM comments"; $comments = mysql_query($SelectComments); $num=mysql_numrows($comments); $variable=mysql_result($comments,$i,"comment"); mysql_close(); ?> <a href="#" onclick="toggle_visibility('hidden');">Show/Hide Comments</a> <?php $i=0; while ($i < $num) { $comment=mysql_result($comments,$i,"comment"); echo "<div id='hidden' style='display:none'><h3>$comment</h3></div>"; $i++; } ?>

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  • Performance of Multiple Joins

    - by geeko
    Greetings Overflowers, I need to query against objects with many/complex spacial conditions. In relational databases that is translated to many joins (possibly 10+). I'm new to this business and wondering whether to go with MS SQL Server 2008 R2 or Oracle 11g or document-based solutions such as RavenDB or simply go with some spacial database (GIS)... Any thoughts ? Regards UPDATE: Thank you all for your answers. Would anybody opt for document/spatial databases ? My database would consist of tens of millions to few billion records. Mostly read-only. Almost no updates unless in case of mistakes in input. Overnight inserts and not that frequent. The join tables are predicted beforehand but the number of self joins (tables joining themselves multiple times) is not. Small pages of results from such queries are going to be viewed on an highly interactive website so response time is critical. Any predictions on how this can perform on MS SQL Server 2008 R2 or Oracle 11g ? I'm also concerned about boosting performance by adding more servers, which one scales better ? How about PostgresQL ?

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  • searching for multiple columns mysql and php

    - by addi
    i'm trying to search for multiple columns using this code: <?php // Connection Database $search = $_POST ['Search']; mysql_connect("xxxxxx", "xxxxxx", "xxxxx") or die ("Error Connecting to Database"); mysql_select_db("xxxxx") or die('Error'); $data = mysql_query("SELECT CourseName, CourseDescription, CourseLeader FROM course MATCH (CourseName, CourseDescription, CourseLeader) AGAINST ('". $search ."') or die('Error'); Print "<table border cellpadding=3>"; while($info = mysql_fetch_array( $data )) { Print "<tr>"; Print "<th>Course Name:</th> <td>".$info['CourseName'] . "</td> "; Print "<th>Course Description:</th><td>".$info['CourseDescription'] . "</td> "; Print "<th>Course Leader:</th><td>".$info['CourseLeader'] . " </td></tr>"; } Print "</table>"; ?> i'm getting the following error: Parse error: syntax error, unexpected T_STRING in /home/a7105766/public_html/website/scripts/coursesearchdb.php on line 30 what am I doing wrong?? cheers

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  • How would you start automating my job?

    - by Jurily
    At my new job, we sell imported stuff. In order to be able to sell said stuff, currently the following things need to happen for every incoming shipment: Invoice arrives, in the form of an email attachment, Excel spreadsheet Monkey opens invoice, copy-pastes the relevant part of three columns into the relevant parts of a spreadsheet template, where extremely complex calculations happen, like =B2*550 Monkey sends this new spreadsheet to boss (email if lucky, printer otherwise), who sets the retail price Monkey opens the reply, then proceeds to input the data into the production database using a client program that is unusable on so many levels it's not even worth detailing Monkey fires up HyperTerminal, types in "AT", disconnect Monkey sends text messages and emails to customers using another part of the horrible client program, one at a time I want to change Monkey from myself to software wherever possible. I've never written anything that interfaces with email, Excel, databases or SMS before, but I'd be more than happy to learn if it saves me from this. Here's my uneducated wishlist: Monkey asks Thunderbird (mail server perhaps?) for the attachment Monkey tells Excel to dump the spreadsheet into a more Jurily-friendly format, like CSV or something Monkey parses the output, does the complex calculations // TODO: find a way to get the boss-generated prices with minimal manual labor involved Monkey connects to the database, inserts data Monkey spams costumers Is all this feasible? If yes, where do I start reading? How would you improve it? What language/framework do you think would be ideal for this? What would you do about the boss?

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  • PEAR:DB connection parameters

    - by Markus Ossi
    I just finished my first PHP site and now I have a security-related question. I used PEAR:DB for the database connection and made a separate parameter file for it. How should I hide this parameter file? I found a guide (http://www.kitebird.com/articles/peardb.html) that says: Another way to specify connection parameters is to put them in a separate file that you reference from your main script. ... It also enables you to move the parameter file outside of the web server's document tree, which prevents its contents from being displayed literally if the server becomes misconfigured and starts serving PHP scripts as plain text. I have now put my file in a directory like this /include/db_parameters.inc However, if I go to this URL, the web server shows me the contents of the file including my database username and password. From what I've understood, I should protect this file so, that even though PHP would be served as text, nobody could read this. What does outside of web server's document tree mean here? Put the PHP file out of public_html directory altogether deeper into the server file system? Some CHMOD?

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  • Convert charset in mysql query

    - by Yousf
    Hi, I have a question about converting charset from inside mysql query. I have a 2 databases. One for the website (joomla), the other for forum (IPB). I am doing query from inside joomla, which by default have "SET NAMES UTF8". I want to query a table inside the forum databases. A table called "ibf_topics". This table has latin1 encoding. I do the following to select anything from the not-utf8 table. //convert connection to handle latin1. $query = "SET NAMES latin1"; $db->setQuery($query); $db->query(); $query = "select id, title from other_database.ibf_topics"; $db->setQuery($query); $db->query(); //read result into an array. //return connection to handle UTF8. $query = "SET NAMES UTF8"; $db->setQuery($query); $db->query(); After that, when I want to use the selected tile, I use the following: echo iconv("CP1256", "UTF-8", $topic['title']) The question is, is there anyway to avoid all this hassle? For now, I can't change forum database to UTF8 and I can't change joomla database to latin1 :S

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  • Complex Quary on cassandra

    - by Sadiqur Rahman
    I have heard on cassandra database engine few days ago and searching for a good documentation on it. after studying on cassandra I got cassandra is more scalable than other data engine. I also read on Amazon SimpleDB but as SimpleDB has a limitation 10GB/table and Google Datastore is slower than Amazon SimpleDB, I prefer not to use them (Google Datastore, Amazon SimpleDB). So for making our site scaled specially high write rates with massive data, I like to use Cassandra as out Data Engine. But before starting using cassandra I am confused on "How to handle complex data using casssandra". I am giving you the MySQL database structure below, Please read this and give me a good suggestion. Users Table hasColum ID Primary hasColum email Unique hasColum FirstName hasColum LastName Category Table hasColum ID Primary hasColum Parent hasColum Category Posts Table hasColum ID Primary hasColum UID Index foreign key linked to users-ID hasColum CID Index foreign key linked to Category-ID hasColum Title hasColum Post Index hasColum PunDate Comments hasColum ID primary hasColum UID Index foreign key linked to users-ID hasColum PID Index foreign key linked to Posts-ID hasColum Comment User Group hasColum ID primary hasColum Name UserToGroup Table (for many to many relation only) hasColum UID foreign key linked to Users-ID hasColum GID foreign key linked to Group-ID Finally for your information, I like to use SimpleCassie PHP Class http://code.google.com/p/simpletools-php/ So, it will be very helpful if you can give me example using SimpleCassie

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  • Have ASP page call save function anytime the user tries to navigate away from page

    - by Breander
    What I have is an input page with a bunch of dynamically created textboxes for the user to input data. The textboxes are dynamically created because the number that are needed are not known until the user selects some options on the page. So what I need to have happen is if the user tries to either A) navigate away from the page or B) select different options bringing up new textboxes. Anything the user may have typed into the textboxes needs to automatically be saved to the database. Like they clicked on the save button on the page. This doesn't sound like a vary smart way to do things or even an easy way to do things but this is the requirement I have been given. No message just save to the database. I have looked into things like onbeforepageunload javascript but that mostly tries to stop the user from navigating away I can't call any code behind code from it. Any help is appreciated. Note : The number of the texboxes with data can be any where between 20 and 500. Yes very crazy but not my idea.

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  • How to retrive user input data entered tab bar View Controller when application start in iphone app

    - by TechFusion
    Hello, I have created window based application. Tab bar controller as root controller and it has three tabs. One Tab has Labels and TextFiled inputs like Name, Username and Password. I am looking to store this text filed inputs when user enters and able retrieve in other tabs. Previously I have set key for different text fields and setobject:withkey task and able to retrive text filed values in same view Controller [[NSUserDefaults standardUserDefaults] stringForKey:key] task. Now I am looking to create database which has different objects and each objects has data values of different Text Field inputs that I can access in whole application. like DatabaseName - Object1 - Name, Username & Password - Object2 - Name, Username & Password Something like structure in Normal C so it would be easy to retrieve data. I am looking NSUserDefaults Class and User Defaults Programming Topics in Cocoa(http://developer.apple.com/iPhone/library/documentation/Cocoa/Conceptual/UserDefaults/UserDefaults.html#//apple_ref/doc/uid/10000059-BCIDJFHD). Also Referring Archives and Serialization Programming guide(http://developer.apple.com/iphone/library/documentation/Cocoa/Conceptual/Archiving/Archiving.html#//apple_ref/doc/uid/10000047i). Which method i need to use to create such type of database ? Thanks,

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  • Is there a way to create subdatabases as a kind of subfolders in sql server?

    - by user193655
    I am creating an application where there is main DB and where other data is stored in secondary databases. The secondary databases follow a "plugin" approach. I use SQL Server. A simple installation of the application will just have the mainDB, while as an option one can activate more "plug-ins" and for every plug-in there will be a new database. Now why I made this choice is because I have to work with an exisiting legacy system and this is the smartest thing I could figure to implement the plugin system. MainDB and Plugins DB have exactly the same schema (basically Plugins DB have some "special content", some important data that one can use as a kind of template - think to a letter template for example - in the application). Plugin DBs are so used in readonly mode, they are "repository of content". The "smart" thing is that the main application can also be used by "plugin writers", they just write a DB inserting content, and by making a backup of the database they creaetd a potential plugin (this is why all DBs has the same schema). Those plugins DB are downloaded from internet as there is a content upgrade available, every time the full PlugIn DB is destroyed and a new one with the same name is creaetd. This is for simplicity and even because the size of this DBs is generally small. Now this works, anyway I would prefer to organize the DBs in a kind of Tree structure, so that I can force the PlugIn DBs to be "sub-DBs" of the main application DB. As a workaround I am thinking of using naming rules, like: ApplicationDB (for the main application DB) ApplicationDB_PlugIn_N (for the N-th plugin DB) When I search for plugin 1 I try to connect to ApplicationDB_PlugIn_1, if I don't find the DB i raise an error. This situation can happen for example if som DBA renamed ApplicationDB_Plugin_1. So since those Plugin DBs are really dependant on ApplicationDB only I was trying to "do the subfolder trick". Can anyone suggest a way to do this? Can you comment on this self-made plugin approach I decribed above?

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  • how to print data in a table from mysql

    - by robertdd
    hello, i want to extract the last eight entries from my database and print them into a 2 columns table!like this: |1|2| |3|4| |5|6| |7|8| is that possible? this is my code: $db = new Database(DB_SERVER, DB_USER, DB_PASS, DB_DATABASE); $db->connect(); $sql = "SELECT ID, movieno FROM movies ORDER BY ID DESC LIMIT 8 "; $rows = $db->query($sql); print '<table width="307" border="0" cellspacing="5" cellpadding="4">'; while ($record = $db->fetch_array($rows)) { $vidaidi = $record['movieno']; print <<<END <tr> <td> <a href="http://www.youtube.com/watch?v=$vidaidi" target="_blank"> <img src="http://img.youtube.com/vi/$vidaidi/1.jpg" width="123" height="80"></a> </td> </tr> END; } print '</table>';

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  • Logic in the db for maintaining a points system relationship?

    - by MarcusBooster
    I'm making a little web based game and need to determine where to put logic that checks the integrity of some underlying data in the sql database. Each user keeps track of points assigned to him, and points are awarded by various tasks. I keep a record of each task transaction to make sure they're not repeated, and to keep track of the value of the task at the time of completion, since an individual award level my fluctuate over time. My schema looks like this so far: create table player ( player_ID serial primary key, player_Points int not null default 0 ); create table task ( task_ID serial primary key, task_PointsAwarded int not null ); create table task_list ( player_ID int references player(player_ID), task_ID int references task(task_ID), when_completed timestamp default current_timestamp, point_value int not null, --not fk because task value may change later constraint pk_player_task_id primary key (player_ID, task_ID) ); So, the player.player_Points should be the total of all his cumulative task points in the task_list. Now where do I put the logic to enforce this? Should I do away with player.player_Points altogether and do queries every time I want to know the total score? Which seems wasteful since I'll be doing that query a lot over the course of a game. Or, put a trigger in the task_list that automatically updates the player.player_Points? Is that too much logic to have in the database and should just maintain this relationship in the application? Thanks.

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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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  • How to store and synchronize a big list of strings

    - by Joel
    I have a large database table in SQLExpress on Windows, with a particular field of interest 'code'. I have an Apache web server with MySQL on Linux. The web application on the Linux box needs access to the list of all codes. The only thing it will use the list for is checking for the existence of a given code. Having the Linux server call out to the Windows server is impractical as the Windows server is behind a NAT'ed office internet connection, and it may not always be accessible. I have set it so the Windows server will push the list of codes to the web server by means of a simple HTTP POST request. However, at this point I have not implemented the storage of the codes on the Linux box. Should I store them in a MySQL table with a single field 'code'? Then I get fast indexed lookups O(1), however I think synchronization will be an issue - given an updated list of codes, pushed from the Windows box, how would I optimally synchronize the list with the database? TRUNCATE, followed by INSERT? Should I instead store them in a flat file? Then I have O(n) look up time rather than O(1). Additionally an extra constant-time overhead too, as I will be processing the file in Ruby. However, synchronization is easy - simply replace the file.

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  • find the difference between two very large list

    - by user157195
    I have two large list(could be a hundred million items), the source of each list can be either from a database table or a flat file. both lists are of comparable sizes, both unsorted. I need to find the difference between them. so I have 3 scenarios: 1. List1 is a database table(assume each row simply have one item(key) that is a string), List2 is a large file. 2. Both lists are from 2 db tables. 3. both lists are from two files. in case 2, I plan to use: select a.item from MyTable a where a.item not in (select b.item form MyTable b) this clearly is inefficient, is there a better way? Another approach is: I plan to sort each list, and then walk down both of them to find the diff. If the list is from a file, I have to read it into a db table first, then use db sorting to output the list. Is the run time complexity still O(nlogn) in db sorting? either approach is a pain and seems would be very slow when the list involved has hundreds of millions of items. any suggestions?

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  • Algorithm for dynamic combinations

    - by sOltan
    My code has a list called INPUTS, that contains a dynamic number of lists, let's call them A, B, C, .. N. These lists contain a dynamic number of Events I would like to call a function with each combination of Events. To illustrate with an example: INPUTS: A(0,1,2), B(0,1), C(0,1,2,3) I need to call my function this many times for each combination (the input count is dynamic, in this example it is three parameter, but it can be more or less) function(A[0],B[0],C[0]) function(A[0],B[1],C[0]) function(A[0],B[0],C[1]) function(A[0],B[1],C[1]) function(A[0],B[0],C[2]) function(A[0],B[1],C[2]) function(A[0],B[0],C[3]) function(A[0],B[1],C[3]) function(A[1],B[0],C[0]) function(A[1],B[1],C[0]) function(A[1],B[0],C[1]) function(A[1],B[1],C[1]) function(A[1],B[0],C[2]) function(A[1],B[1],C[2]) function(A[1],B[0],C[3]) function(A[1],B[1],C[3]) function(A[2],B[0],C[0]) function(A[2],B[1],C[0]) function(A[2],B[0],C[1]) function(A[2],B[1],C[1]) function(A[2],B[0],C[2]) function(A[2],B[1],C[2]) function(A[2],B[0],C[3]) function(A[2],B[1],C[3]) This is what I have thought of so far: My approach so far is to build a list of combinations. The element combination is itself a list of "index" to the input arrays A, B and C. For our example: my list iCOMBINATIONS contains the following iCOMBO lists (0,0,0) (0,1,0) (0,0,1) (0,1,1) (0,0,2) (0,1,2) (0,0,3) (0,1,3) (1,0,0) (1,1,0) (1,0,1) (1,1,1) (1,0,2) (1,1,2) (1,0,3) (1,1,3) (2,0,0) (2,1,0) (2,0,1) (2,1,1) (2,0,2) (2,1,2) (2,0,3) (2,1,3) Then I would do this: foreach( iCOMBO in iCOMBINATIONS) { foreach ( P in INPUTS ) { COMBO.Clear() foreach ( i in iCOMBO ) { COMBO.Add( P[ iCOMBO[i] ] ) } function( COMBO ) --- (instead of passing the events separately) } } But I need to find a way to build the list iCOMBINATIONS for any given number of INPUTS and their events. Any ideas? Is there actually a better algorithm than this? any pseudo code to help me with will be great. C# (or VB) Thank You

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  • Disk Search / Sort Algorithm

    - by AlgoMan
    Given a Range of numbers say 1 to 10,000, Input is in random order. Constraint: At any point only 1000 numbers can be loaded to memory. Assumption: Assuming unique numbers. I propose the following efficient , "When-Required-sort Algorithm". We write the numbers into files which are designated to hold particular range of numbers. For example, File1 will have 0 - 999 , File2 will have 1000 - 1999 and so on in random order. If a particular number which is say "2535" is being searched for then we know that the number is in the file3 (Binary search over range to find the file). Then file3 is loaded to memory and sorted using say Quick sort (which is optimized to add insertion sort when the array size is small ) and then we search the number in this sorted array using Binary search. And when search is done we write back the sorted file. So in long run all the numbers will be sorted. Please comment on this proposal.

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  • Why were namespaces removed from ECMAScript consideration?

    - by Bob
    Namespaces were once a consideration for ECMAScript (the old ECMAScript 4) but were taken out. As Brendan Eich says in this message: One of the use-cases for namespaces in ES4 was early binding (use namespace intrinsic), both for performance and for programmer comprehension -- no chance of runtime name binding disagreeing with any earlier binding. But early binding in any dynamic code loading scenario like the web requires a prioritization or reservation mechanism to avoid early versus late binding conflicts. Plus, as some JS implementors have noted with concern, multiple open namespaces impose runtime cost unless an implementation works significantly harder. For these reasons, namespaces and early binding (like packages before them, this past April) must go. But I'm not sure I understand all of that. What exactly is a prioritization or reservation mechanism and why would either of those be needed? Also, must early binding and namespaces go hand-in-hand? For some reason I can't wrap my head around the issues involved. Can anyone attempt a more fleshed out explanation? Also, why would namespaces impose runtime costs? In my mind I can't help but see little difference in concept between a namespace and a function using closures. For instance, Yahoo and Google both have YAHOO and google objects that "act like" namespaces in that they contain all of their public and private variables, functions, and objects within a single access point. So why, then, would a namespace be so significantly different in implementation? Maybe I just have a misconception as to what a namespace is exactly.

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  • "'0.offsetWidth' is null or not an object" - Coda Slider - Javascript Error Question

    - by bgadoci
    I implemented the Coda Slider tutorial successfully that is located here: http://jqueryfordesigners.com/coda-slider-effect/ The slider works great but I am getting a javascript error that I am not sure how to fix. The error says: '0.offsetWidth' is null or not an object coda-slider.js, line 19 character 3 Not sure how to fix it. Anyone have any ideas? Here is my js and css (don't think I need to upload the HTML but let me know if that helps). JS (coda-slider.js) // when the DOM is ready... $(document).ready(function () { var $panels = $('#slider .scrollContainer > div'); var $container = $('#slider .scrollContainer'); // if false, we'll float all the panels left and fix the width // of the container var horizontal = true; // float the panels left if we're going horizontal if (horizontal) { $panels.css({ 'float' : 'left', 'position' : 'relative' // IE fix to ensure overflow is hidden }); // calculate a new width for the container (so it holds all panels) $container.css('width', $panels[0].offsetWidth * $panels.length); <------line 19 } // collect the scroll object, at the same time apply the hidden overflow // to remove the default scrollbars that will appear var $scroll = $('#slider .scroll').css('overflow', 'hidden'); // apply our left + right buttons $scroll .before('<img class="scrollButtons left" src="/images/layout/navigation/scroll_left.png" />') .after('<img class="scrollButtons right" src="/images/layout/navigation/scroll_right.png" />'); // handle nav selection function selectNav() { $(this) .parents('ul:first') .find('a') .removeClass('selected') .end() .end() .addClass('selected'); } $('#slider .navigation').find('a').click(selectNav); // go find the navigation link that has this target and select the nav function trigger(data) { var el = $('#slider .navigation').find('a[href$="' + data.id + '"]').get(0); selectNav.call(el); } if (window.location.hash) { trigger({ id : window.location.hash.substr(1) }); } else { $('ul.navigation a:first').click(); } // offset is used to move to *exactly* the right place, since I'm using // padding on my example, I need to subtract the amount of padding to // the offset. Try removing this to get a good idea of the effect var offset = parseInt((horizontal ? $container.css('paddingTop') : $container.css('paddingLeft')) || 0) * -1; var scrollOptions = { target: $scroll, // the element that has the overflow // can be a selector which will be relative to the target items: $panels, navigation: '.navigation a', // selectors are NOT relative to document, i.e. make sure they're unique prev: 'img.left', next: 'img.right', // allow the scroll effect to run both directions axis: 'xy', onAfter: trigger, // our final callback offset: offset, // duration of the sliding effect duration: 500, // easing - can be used with the easing plugin: // http://gsgd.co.uk/sandbox/jquery/easing/ easing: 'swing' }; // apply serialScroll to the slider - we chose this plugin because it // supports// the indexed next and previous scroll along with hooking // in to our navigation. $('#slider').serialScroll(scrollOptions); // now apply localScroll to hook any other arbitrary links to trigger // the effect $.localScroll(scrollOptions); // finally, if the URL has a hash, move the slider in to position, // setting the duration to 1 because I don't want it to scroll in the // very first page load. We don't always need this, but it ensures // the positioning is absolutely spot on when the pages loads. scrollOptions.duration = 1; $.localScroll.hash(scrollOptions); }); CSS #slider { margin-left: 35px; position: relative; width: 875px; } .scroll { position: relative; width: 875px; height: 268px; overflow: auto; /* fix for IE to respect overflow */ background: #FFFFFF scroll 0; } .scrollContainer div.panel { position: relative; height: 210px; width: 875px; /* change to 560px if not using JS to remove rh.scroll */ } .scrollButtons { position: absolute; top: 115px; cursor: pointer; } .scrollButtons.left { left: -20px; } .scrollButtons.right { right: -20px; }

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