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  • subsonic . navigate among records ,view,query

    - by gmo camilo
    hello everybody i'm some newbie in this matter of .net i'm trying understand this new paradigm i began with linq for SQl but i found this library, kind of framework of T4 more specifically: subsonic T4 i think it could be very usefull but the support docs outside are very scarce my first intention is use them in the very simple form: a catalog lets say... Users so... how can i use the model generated with subsonic ( using the iactiverecord) to implement the record-navigational part.,...???!!! i mean i want a simple form to create, delete or modify records and that is fairy easy but what about to move among records ? i found how to get the first, the last record.. but how can i advance or go back among them??? how can i order the records..? it seems everytime imust query the table.. its so? but how can imove among the records i already got? all of the exmples found are very simple dont touch the matter and/ or are repetitive everywhere so.. please if anybody can help me or give more references... i'd thank you a lot gmo camilo

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  • how to select the min value using having key word

    - by LOVE_KING
    I have created the table stu_dep_det CREATE TABLE `stu_dept_cs` ( `s_d_id` int(10) unsigned NOT NULL auto_increment, `stu_name` varchar(15) , `gender` varchar(15) , `address` varchar(15),`reg_no` int(10) , `ex_no` varchar(10) , `mark1` varchar(10) , `mark2` varchar(15) , `mark3` varchar(15) , `total` varchar(15) , `avg` double(2,0), PRIMARY KEY (`s_d_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC AUTO_INCREMENT=8 ; then Inserted the values INSERT INTO `stu_dept_cs` (`s_d_id`, `stu_name`, `gender`, `address`, `reg_no`, `ex_no`, `mark1`, `mark2`, `mark3`, `total`, `avg`) VALUES (1, 'alex', 'm', 'chennai', 5001, 's1', '70', '90', '95', '255', 85), (2, 'peter', 'm', 'chennai', 5002, 's1', '80', '70', '90', '240', 80), (6, 'parv', 'f', 'mumbai', 5003, 's1', '88', '60', '80', '228', 76), (7, 'basu', 'm', 'kolkatta', 5004, 's1', '85', '95', '56', '236', 79); I want to select the min(avg) using having keyword and I have used the following sql statement SELECT * FROM stu_dept_cs s having min(avg) Is it correct or not plz write the correct ans....

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  • HttpWebRequest is extremely slow!

    - by Earlz
    Hello, I am using an open source library to connect to my webserver. I was concerned that the webserver was going extremely slow and then I tried doing a simple test in Ruby and I got these results Ruby program: 2.11seconds for 100 HTTP GETs C# library: 20.81seconds for 100 HTTP GETs I have profiled and found the problem to be this function: private HttpWebResponse GetRawResponse(HttpWebRequest request) { HttpWebResponse raw = null; try { raw = (HttpWebResponse)request.GetResponse(); //This line! } catch (WebException ex) { if (ex.Response is HttpWebResponse) { raw = ex.Response as HttpWebResponse; } } return raw; } The marked line is takes over 1 second to complete by itself while the ruby program making 1 request takes .3 seconds. I am also doing all of these tests on 127.0.0.1, so network bandwidth is not an issue. What could be causing this huge slow down?

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  • how to profile silverlight mvvm application with a lot of custom controls

    - by tomo
    There is a quite big LOB silverlight application and we wrote a lot of custom controls which are rather heavy in drawing. All data is loaded by RIA service, processed and bound (using INofityPropertyChanged interface) to the view. The problem is that first drawing takes a lot time. Following calls to the service (server) and redrawing is quite fast. I used Equatec profiler to track the problem. I saw that processing takes a couple of miliseconds only so my idea is that the drawing by SL engine is slow. I'm wondering if it is possible to profile somehow processes inside SL to check which drawing operations are taking too much time. Are there any guidelines how to implement faster drawing of complex custom controls?

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  • Which is faster in Python: x**.5 or math.sqrt(x)?

    - by Casey
    I've been wondering this for some time. As the title say, which is faster, the actual function or simply raising to the half power? UPDATE This is not a matter of premature optimization. This is simply a question of how the underlying code actually works. What is the theory of how Python code works? I sent Guido van Rossum an email cause I really wanted to know the differences in these methods. My email: There are at least 3 ways to do a square root in Python: math.sqrt, the '**' operator and pow(x,.5). I'm just curious as to the differences in the implementation of each of these. When it comes to efficiency which is better? His response: pow and ** are equivalent; math.sqrt doesn't work for complex numbers, and links to the C sqrt() function. As to which one is faster, I have no idea...

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  • High CPU Usage with WebGL?

    - by shoosh
    I'm checking out the nightly builds of Firefox and Chromium with support of WebGL with a few demos and tutorials and I can't help but wonder about the extremely high CPU load they cause. A simple demo like this one runs at a sustained 60% of my dual core. The large version of this one maxes out the CPU to 100% and has some visible frame loss. Chromium seems to be slightly better than firefox but not by much. I'm pretty sure that if these were desktop application the CPU load would be negligible. So what's going on here? what is it doing? Running the simple scripts of these can't be that demanding. Is it the extra layer of security or something?

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  • mysql database normalization question

    - by Chocho
    here is my 3 tables: table 1 -- stores user information and it has unique data table 2 -- stores place category such as, toronto, ny, london, etc hence this is is also unique table 3 -- has duplicate information. it stores all the places a user have been. the 3 tables are linked or joined by these ids: table 1 has an "table1_id" table 2 has an "table2_id" and "place_name" table 3 has an "table3_id", "table1_id", "place_name" i have an interface where an admin sees all users. beside a user is "edit" button. clicking on that edit button allows you to edit a specific user in a form fields which has a multiple drop down box for "places". if an admin edits a user and add 1 "places" for the user, i insert that information using php. if the admin decides to deselect that 1 "places" do i delete it or mark it as on and off? how about if the admin decides to select 2 "places" for the user; change the first "places" and add an additional "places". will my table just keep growing and will i have just redundant information? thanks.

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  • Python: Why is IDLE so slow?

    - by Adam Matan
    Hi, IDLE is my favorite Python editor. It offers very nice and intuitive Python shell which is extremely useful for unit-testing and debugging, and a neat debugger. However, code executed under IDLE is insanely slow. By insanely I mean 3 orders of magnitude slow: bash time echo "for i in range(10000): print 'x'," | python Takes 0.052s, IDLE import datetime start=datetime.datetime.now() for i in range(10000): print 'x', end=datetime.datetime.now() print end-start Takes: >>> 0:01:44.853951 Which is roughly 2,000 times slower. Any thoughts, or ideas how to improve this? I guess it has something to do with the debugger in the background, but I'm not really sure. Adam

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  • Cache of Objects or OutPut in View ? Wich is better ?

    - by Felipe
    Hi everybody, I have an ecommerce working in ASP.Net MVC. i'm using Caching to improve more performace in my pages and it's working fine. I'd link to know what is more performative, for example, I can set OutPutCache in my views and and use this cache for all page OR I could get my List of Products in controller, put it on cache (like the code below) and send it to View to render for the user??? private IEnumerable<Products> GetProductsCache(string key, ProductType type) { if (HttpContext.Cache[key] == null) HttpContext.Cache.Insert(key, ProductRepository.GetProducts(type), null, DateTime.Now.AddMinutes(10), Cache.NoSlidingExpiration); return (IEnumerable<Products>)HttpContext.Cache[key]; } public ActionResult Index() { var home = new HomeViewModel() { Products = GetProductsCache("ProductHomeCache", ProductType.Product) Services = GetProductsCache("ServiceHomeCache", ProductType.Service) }; return View(home); } Both works fine, but I'd like to know what is suggested to improve more performace ? Or is there others way to do it better ? PS: sorry for my english! thanks all... Cheers

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  • Benchmarking a particular method in Objective-C

    - by Jasconius
    I have a critical method in an Objective-C application that I need to optimize as much as possible. I first need to take some easy benchmarks on this one single method so I can compare my progress as I optimize. What is the easiest way to track the execution time of a given method in, say, milliseconds, and print that to console.

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  • database design to speed up hibernate querying of large dataset

    - by paddydub
    I currently have the below tables representing a bus network mapped in hibernate, accessed from a Spring MVC based bus route planner I'm trying to make my route planner application perform faster, I load all the above tables into Lists to perform the route planner logic. I would appreciate if anyone has any ideas of how to speed my performace Or any suggestions of another method to approach this problem of handling a large set of data Coordinate Connections Table (INT,INT,INT)( Containing 50,000 Coordinate Connections) ID, FROMCOORDID, TOCOORDID 1 1 2 2 1 17 3 1 63 4 1 64 5 1 65 6 1 95 Coordinate Table (INT,DECIMAL, DECIMAL) (Containing 4700 Coordinates) ID , LAT, LNG 0 59.352669 -7.264341 1 59.352669 -7.264341 2 59.350012 -7.260653 3 59.337585 -7.189798 4 59.339221 -7.193582 5 59.341408 -7.205888 Bus Stop Table (INT, INT, INT)(Containing 15000 Stops) StopID RouteID COORDINATEID 1000100001 100 17 1000100002 100 18 1000100003 100 19 1000100004 100 20 1000100005 100 21 1000100006 100 22 1000100007 100 23 This is how long it takes to load all the data from each table: stop.findAll = 148ms, stops.size: 15670 Hibernate: select coordinate0_.COORDINATEID as COORDINA1_2_, coordinate0_.LAT as LAT2_, coordinate0_.LNG as LNG2_ from COORDINATES coordinate0_ coord.findAll = 51ms , coordinates.size: 4704 Hibernate: select coordconne0_.COORDCONNECTIONID as COORDCON1_3_, coordconne0_.DISTANCE as DISTANCE3_, coordconne0_.FROMCOORDID as FROMCOOR3_3_, coordconne0_.TOCOORDID as TOCOORDID3_ from COORDCONNECTIONS coordconne0_ coordinateConnectionDao.findAll = 238ms ; coordConnectioninates.size:48132 Hibernate Annotations @Entity @Table(name = "STOPS") public class Stop implements Serializable { @Id @GeneratedValue @Column(name = "COORDINATEID") private Integer CoordinateID; @Column(name = "LAT") private double latitude; @Column(name = "LNG") private double longitude; } @Table(name = "COORDINATES") public class Coordinate { @Id @GeneratedValue @Column(name = "COORDINATEID") private Integer CoordinateID; @Column(name = "LAT") private double latitude; @Column(name = "LNG") private double longitude; } @Entity @Table(name = "COORDCONNECTIONS") public class CoordConnection { @Id @GeneratedValue @Column(name = "COORDCONNECTIONID") private Integer CoordinateID; /** * From Coordinate_id value */ @Column(name = "FROMCOORDID", nullable = false) private int fromCoordID; /** * To Coordinate_id value */ @Column(name = "TOCOORDID", nullable = false) private int toCoordID; //private Coordinate toCoordID; }

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  • Why does appending "" to a String save memory?

    - by hsmit
    I used a variable with a lot of data in it, say String data. I wanted to use a small part of this string in the following way: this.smallpart = data.substring(12,18); After some hours of debugging (with a memory visualizer) I found out that the objects field smallpart remembered all the data from data, although it only contained the substring. When I changed the code into: this.smallpart = data.substring(12,18)+""; ..the problem was solved! Now my application uses very little memory now! How is that possible? Can anyone explain this? I think this.smallpart kept referencing towards data, but why? UPDATE: How can I clear the big String then? Will data = new String(data.substring(0,100)) do the thing?

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  • showing null rows using join

    - by Pradyut Bhattacharya
    Hi, In mysql i m selecting from a table shouts having a foreign key to another table named "roleuser" with the matching column as user_id Now the user_id column in the shouts table for some rows is null (not actually null but with no inserts in mysql) How to show all the rows of the shouts table either with user_id null or not I m executing the sql statement SELECT s.*, r.firstname, r.lastname FROM shouts s left join roleuser r where r.user_id = s.user_id limit 50; which does not executes and shows You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'where r.user_id = s.user_id limit 50' at line 2 but using inner join the sql executes which shows rows which only have user_id values in the shouts table. the nulls are not shown. SELECT s.*, r.firstname, r.lastname FROM shouts s inner join roleuser r where r.user_id = s.user_id limit 50; How can i show all the rows from the shouts table and null values in the firstname and lastname columns where the user_id is null in the shouts table. If not at all possible with sql may be using stored procedures... Thanks Pradyut

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  • Error in asp.net c# code (mysql database connection)

    - by Ishan
    My code is to update a record if it already exists in database else insert as a new record. My code is as follows: protected void Button3_Click(object sender, EventArgs e) { OdbcConnection MyConnection = new OdbcConnection("Driver={MySQL ODBC 3.51 Driver};Server=localhost;Database=testcase;User=root;Password=root;Option=3;"); MyConnection.Open(); String MyString = "select fil_no,orderdate from temp_save where fil_no=? and orderdate=?"; OdbcCommand MyCmd = new OdbcCommand(MyString, MyConnection); MyCmd.Parameters.AddWithValue("", HiddenField4.Value); MyCmd.Parameters.AddWithValue("", TextBox3.Text); using (OdbcDataReader MyReader4 = MyCmd.ExecuteReader()) { //** if (MyReader4.Read()) { String MyString1 = "UPDATE temp_save SET order=? where fil_no=? AND orderdate=?"; OdbcCommand MyCmd1 = new OdbcCommand(MyString1, MyConnection); MyCmd1.Parameters.AddWithValue("", Editor1.Content.ToString()); MyCmd1.Parameters.AddWithValue("", HiddenField1.Value); MyCmd1.Parameters.AddWithValue("", TextBox3.Text); MyCmd1.ExecuteNonQuery(); } else { // set the SQL string String strSQL = "INSERT INTO temp_save (fil_no,order,orderdate) " + "VALUES (?,?,?)"; // Create the Command and set its properties OdbcCommand objCmd = new OdbcCommand(strSQL, MyConnection); objCmd.Parameters.AddWithValue("", HiddenField4.Value); objCmd.Parameters.AddWithValue("", Editor1.Content.ToString()); objCmd.Parameters.AddWithValue("", TextBox3.Text); // execute the command objCmd.ExecuteNonQuery(); } } } I am getting the error as: ERROR [42000] [MySQL][ODBC 3.51 Driver][mysqld-5.1.51-community]You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'order,orderdate) VALUES ('04050040272009','&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&' at line 1 The datatype for fields in table temp_save are: fil_no-->INT(15)( to store a 15 digit number) order-->LONGTEXT(to store contents from HTMLEditor(ajax control)) orderdate-->DATE(to store date) Please help me to resolve my error.

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  • Linux 2.6.31 Scheduler and Multithreaded Jobs

    - by dsimcha
    I run massively parallel scientific computing jobs on a shared Linux computer with 24 cores. Most of the time my jobs are capable of scaling to 24 cores when nothing else is running on this computer. However, it seems like when even one single-threaded job that isn't mine is running, my 24-thread jobs (which I set for high nice values) only manage to get ~1800% CPU (using Linux notation). Meanwhile, about 500% of the CPU cycles (again, using Linux notation) are idle. Can anyone explain this behavior and what I can do about it to get all of the 23 cores that aren't being used by someone else? Notes: In case it's relevant, I have observed this on slightly different kernel versions, though I can't remember which off the top of my head. The CPU architecture is x64. Is it at all possible that the fact that my 24-core jobs are 32-bit and the other jobs I'm competing w/ are 64-bit is relevant? Edit: One thing I just noticed is that going up to 30 threads seems to alleviate the problem to some degree. It gets me up to ~2100% CPU.

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  • How can I update multiple columns with a Replace in SQL server?

    - by Kettenbach
    How do I update different columns and rows across a table? I want to do something similiar to replace a string in SQL server I want to do this but the value exists in multiple columns of the same type. The values are foreign keys varchars to an employee table. Each column represents a task, so the same employee may be assigned to several tasks in a record and those tasks will vary between records. How can I do this effectively? Basically something of a replace all accross varying columns throughout a table. Thanks for any help or advice. Cheers, ~ck in San Diego

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  • Database INSERT does not take place

    - by reggie
    My code is as follows: <?php include("config.php"); $ip=$_SERVER['REMOTE_ADDR']; if($_POST['id']) { $id=$_POST['id']; $id = mysql_escape_String($id); $ip_sql=mysql_query("select ip_add from Voting_IP where mes_id_fk='$id' and ip_add='$ip'"); $count=mysql_num_rows($ip_sql); if($count==0) { $sql = "update Messages set up=up+1 where mes_id='$id'"; mysql_query($sql); $sql_in = "insert into Voting_IP (mes_id_fk,ip_add) values ('$id','$ip')"; mysql_query($sql_in) or die(mysql_error()); echo "<script>alert('Thanks for the vote');</script>"; } else { echo "<script>alert('You have already voted');</script>"; } $result=mysql_query("select up from Messages where mes_id='$id'"); $row=mysql_fetch_array($result); $up_value=$row['up']; echo "<img src='button.png' width='110' height='90'>"; echo $up_value; } ?> My problem is that the insert process does not take place at all. The script tags echos an alert box. Even the img tag is echoed to the web page. But the insert process does not take place. The config file is fine. Note: This code works on my local machine which has PHP 5.3 but it does not work on the server which has PHP 5.2. Any advice?

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  • Is SQL Server DRI (ON DELETE CASCADE) slow?

    - by Aaronaught
    I've been analyzing a recurring "bug report" (perf issue) in one of our systems related to a particularly slow delete operation. Long story short: It seems that the CASCADE DELETE keys were largely responsible, and I'd like to know (a) if this makes sense, and (b) why it's the case. We have a schema of, let's say, widgets, those being at the root of a large graph of related tables and related-to-related tables and so on. To be perfectly clear, deleting from this table is actively discouraged; it is the "nuclear option" and users are under no illusions to the contrary. Nevertheless, it sometimes just has to be done. The schema looks something like this: Widgets | +--- Anvils (1:1) | | | +--- AnvilTestData (1:N) | +--- WidgetHistory (1:N) | +--- WidgetHistoryDetails (1:N) Nothing too scary, really. A Widget can be different types, an Anvil is a special type, so that relationship is 1:1 (or more accurately 1:0..1). Then there's a large amount of data - perhaps thousands of rows of AnvilTestData per Anvil collected over time, dealing with hardness, corrosion, exact weight, hammer compatibility, usability issues, and impact tests with cartoon heads. Then every Widget has a long, boring history of various types of transactions - production, inventory moves, sales, defect investigations, RMAs, repairs, customer complaints, etc. There might be 10-20k details for a single widget, or none at all, depending on its age. So, unsurprisingly, there's a CASCADE DELETE relationship at every level here. If a Widget needs to be deleted, it means something's gone terribly wrong and we need to erase any records of that widget ever existing, including its history, test data, etc. Again, nuclear option. Relations are all indexed, statistics are up to date. Normal queries are fast. The system tends to hum along pretty smoothly for everything except deletes. Getting to the point here, finally, for various reasons we only allow deleting one widget at a time, so a delete statement would look like this: DELETE FROM Widgets WHERE WidgetID = @WidgetID Pretty simple, innocuous looking delete... that takes over 2 minutes to run, for a widget with no data! After slogging through execution plans I was finally able to pick out the AnvilTestData and WidgetHistoryDetails deletes as the sub-operations with the highest cost. So I experimented with turning off the CASCADE (but keeping the actual FK, just setting it to NO ACTION) and rewriting the script as something very much like the following: DECLARE @AnvilID int SELECT @AnvilID = AnvilID FROM Anvils WHERE WidgetID = @WidgetID DELETE FROM AnvilTestData WHERE AnvilID = @AnvilID DELETE FROM WidgetHistory WHERE HistoryID IN ( SELECT HistoryID FROM WidgetHistory WHERE WidgetID = @WidgetID) DELETE FROM Widgets WHERE WidgetID = @WidgetID Both of these "optimizations" resulted in significant speedups, each one shaving nearly a full minute off the execution time, so that the original 2-minute deletion now takes about 5-10 seconds - at least for new widgets, without much history or test data. Just to be absolutely clear, there is still a CASCADE from WidgetHistory to WidgetHistoryDetails, where the fanout is highest, I only removed the one originating from Widgets. Further "flattening" of the cascade relationships resulted in progressively less dramatic but still noticeable speedups, to the point where deleting a new widget was almost instantaneous once all of the cascade deletes to larger tables were removed and replaced with explicit deletes. I'm using DBCC DROPCLEANBUFFERS and DBCC FREEPROCCACHE before each test. I've disabled all triggers that might be causing further slowdowns (although those would show up in the execution plan anyway). And I'm testing against older widgets, too, and noticing a significant speedup there as well; deletes that used to take 5 minutes now take 20-40 seconds. Now I'm an ardent supporter of the "SELECT ain't broken" philosophy, but there just doesn't seem to be any logical explanation for this behaviour other than crushing, mind-boggling inefficiency of the CASCADE DELETE relationships. So, my questions are: Is this a known issue with DRI in SQL Server? (I couldn't seem to find any references to this sort of thing on Google or here in SO; I suspect the answer is no.) If not, is there another explanation for the behaviour I'm seeing? If it is a known issue, why is it an issue, and are there better workarounds I could be using?

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  • yuicompressor error, not sure what is wrong?

    - by mrblah
    Hi, Very confused here, trying out the yuicompressor on a simple javascript file. My js file looks like: function splitText(text) { return text.split('-')[1]; } The error is: [INFO] Using charset Cp1252 [Error] 1:20:illegal character [Error] 1:20:syntax error [Error] 1:40:illegal character [Error] 1:49:missing ; before statement [Error] 1:50:illegal character .. .. [Error] 7:3:missing | in compound statement [error] 1:0:compilation produced 38 syntax errors ... Can someone please explain to me what is wrong?

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  • Is there a fast way to jump to element using XMLReader?

    - by Derk
    I am using XMLReader to read a large XML file with about 1 million elements on the level I am reading from. However, I've calculated it will take over 10 seconds when I jump to -for instance- element 500.000 using XMLReader::next ([ string $localname ] ) or XMLReader::read ( void ) This is not very usable. Is there a faster way to do this?

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  • Indexing only one MySQL column value

    - by BrainCore
    I have a MySQL InnoDB table with a status column. The status can be 'done' or 'processing'. As the table grows, at most .1% of the status values will be 'processing,' whereas the other 99.9% of the values will be 'done.' This seems like a great candidate for an index due to the high selectivity for 'processing' (though not for 'done'). Is it possible to create an index for the status column that only indexes the value 'processing'? I do not want the index to waste an enormous amount of space indexing 'done.'

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  • Retrieving many huge sized EPS files and converting them to JPEG in ASP.NET application

    - by Ashish Gupta
    I have many (600) EPS files(300 KB - 1 MB) in database. In my ASP.NET application (using ASP.NET 4.0) I need to retrieve them one by one and call a web service which would convert the content to the JPEG file and update the database (JPEGContent column with the JPEG content). However, retrieving the content for 600 of them itself takes too long from the SQL management studio itself (takes 5 minutes for 10 EPS contents). So I have two issues:- 1) How to get the EPS content ( unfortunately, selecting certain number of content is not an option :-( ):- Approach 1:- foreach(var DataRow in DataTable.Rows) { // get the Id and byte[] of EPS // Call the web method to convert EPS content to JPEG which would also update the database. } or foreach(var DataRow in DataTable.Rows) { // get only the Id of EPS // Hit database to get the content of EPS // Call the web method to convert EPS content to JPEG which would also update the database. } or Any other approach? 2) Converting EPS to JPEG using a web method for 600 contents. Ofcourse, each call would be a long running operation. Would task parellel library (TPL) be a better way to achieve this? Also, is doing the entire thing in a SQL CLR function a good idea?

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  • The "first past the post election" query problem

    - by MPelletier
    This problem may seem like school work, but it isn't. At best it is self-imposed school work. I encourage any teachers to take is as an example if they wish. "First past the post" elections are single-round, meaning that whoever gets the most votes win, no second rounds. Suppose a table for an election. CREATE TABLE ElectionResults ( DistrictHnd INTEGER NOT NULL, PartyHnd INTEGER NOT NULL, CandidateName VARCHAR2(100) NOT NULL, TotalVotes INTEGER NOT NULL, PRIMARY KEY DistrictHnd, PartyHnd); The table has two foreign keys: DistrictHnd points to a District table (lists all the different electoral districts) and PartyHnd points to a Party table (lists all the different political parties). I won't bother with other tables here, joining them is trivial. This is just a wee bit of context. The question: What SQL query will return a table listing the DistrictHnd, PartyHnd, CandidateName and TotalVotes of the winners (max votes) in each District? This does not suppose any particular database system. If you wish to stick to a particular implementation of SQL, go the way of SQLite and MySQL. If you can devise a better schema (or an easier one), that is acceptable too. Criteria: simplicity, portability to other databases.

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