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  • Guides for PostgreSQL query tuning?

    - by Joe
    I've found a number of resources that talk about tuning the database server, but I haven't found much on the tuning of the individual queries. For instance, in Oracle, I might try adding hints to ignore indexes or to use sort-merge vs. correlated joins, but I can't find much on tuning Postgres other than using explicit joins and recommendations when bulk loading tables. Do any such guides exist so I can focus on tuning the most run and/or underperforming queries, hopefully without adversely affecting the currently well-performing queries? I'd even be happy to find something that compared how certain types of queries performed relative to other databases, so I had a better clue of what sort of things to avoid. update: I should've mentioned, I took all of the Oracle DBA classes along with their data modeling and SQL tuning classes back in the 8i days ... so I know about 'EXPLAIN', but that's more to tell you what's going wrong with the query, not necessarily how to make it better. (eg, are 'while var=1 or var=2' and 'while var in (1,2)' considered the same when generating an execution plan? What if I'm doing it with 10 permutations? When are multi-column indexes used? Are there ways to get the planner to optimize for fastest start vs. fastest finish? What sort of 'gotchas' might I run into when moving from mySQL, Oracle or some other RDBMS?) I could write any complex query dozens if not hundreds of ways, and I'm hoping to not have to try them all and find which one works best through trial and error. I've already found that 'SELECT count(*)' won't use an index, but 'SELECT count(primary_key)' will ... maybe a 'PostgreSQL for experienced SQL users' sort of document that explained sorts of queries to avoid, and how best to re-write them, or how to get the planner to handle them better. update 2: I found a Comparison of different SQL Implementations which covers PostgreSQL, DB2, MS-SQL, mySQL, Oracle and Informix, and explains if, how, and gotchas on things you might try to do, and his references section linked to Oracle / SQL Server / DB2 / Mckoi /MySQL Database Equivalents (which is what its title suggests) and to the wikibook SQL Dialects Reference which covers whatever people contribute (includes some DB2, SQLite, mySQL, PostgreSQL, Firebird, Vituoso, Oracle, MS-SQL, Ingres, and Linter).

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  • PCRE multi line matche problem

    - by Simone Margaritelli
    Hi guys, i have this C++ program (actually it's just a snippet) : #include <iostream> #include <pcre.h> #include <string> using namespace std; int main(){ string pattern = "<a\\s+href\\s*=\\s*\"([^\"]+)\"", html = "<html>\n" "<body>\n" "<a href=\"example_link_1\"/>\n" "<a href=\"example_link_2\"/>\n" "<a href=\"example_link_3\"/>\n" "</body>\n" "</html>"; int i, ccount, rc, *offsets, eoffset; const char *error; pcre *compiled; compiled = pcre_compile( pattern.c_str(), PCRE_CASELESS | PCRE_MULTILINE, &error, &eoffset, 0 ); if( !compiled ){ cerr << "Error compiling the regexp!!" << endl; return 0; } rc = pcre_fullinfo( compiled, 0, PCRE_INFO_CAPTURECOUNT, &ccount ); offsets = new int[ 3 * (ccount + 1) ]; rc = pcre_exec( compiled, 0, html.c_str(), html.length(), 0, 0, offsets, 3 * (ccount + 1) ); if( rc >= 0 ){ for( i = 1; i < rc; ++i ){ cout << "Match : " << html.substr( offsets[2*i], offsets[2*i+1] - offsets[2*i] ) << endl; } } else{ cout << "Sorry, no matches!" << endl; } delete [] offsets; return 0; } As you can see, i'm trying to match html links inside a buffer with the given regular expression (the \\s is \s escaped for C/C++ strings). But, even if in the buffer there are 3 links and the regexp is compiled with the PCRE_CASELESS and PCRE_MULTILINE flags, i match only one element : Match : example_link_1 Note: I start the loop fro index 1 because the pcre library returns the string that matched (not the match itself) as the first element, and the matches follows. What's wrong with this code? The regexp itself i think it's correct (tried in PHP for instance).

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  • Scheme Formatting Help

    - by Logan
    I've been working on a project for school that takes functions from a class file and turns them into object/classes. The assignment is all about object oriented programming in scheme. My problem however is that my code doesn't format right. The output it gives me whenever I give it a file to pass in wraps the methods of the class in a list, making it so that the class never really gets declared. I can't for the life of me figure out how to get the parenthesis wrapping the method list to remove. I would really appreciate any help. Below is the code and the class file. ;;;; PART1 --- A super-easy set of classes. Just models points and lines. Tests all of the ;; basics of class behavior without touching on anything particularly complex. (class pointInstance (parent:) (constructor_args:) (ivars: (myx 1) (myy 2)) (methods: (getx () myx) (gety () myy) (setx (x) (set! myx x)) (show () (begin (display "[") (display myx) (display ",") (display myy) (display "]"))) )) (require (lib "trace.ss")) ;; Continue reading until you hit the end of the file, all the while ;; building a list with the contents (define load-file (lambda (port) (let ((rec (read port))) (if (eof-object? rec) '() (cons rec (load-file port)))))) ;; Open a port based on a file name using open-input-file (define (load fname) (let ((fport (open-input-file fname))) (load-file fport))) ;(define lis (load "C:\\Users\\Logan\\Desktop\\simpletest.txt")) ;(define lis (load "C:\\Users\\Logan\\Desktop\\complextest.txt")) (define lis (load "C:\\Users\\Logan\\Desktop\\pointinstance.txt")) ;(display (cdaddr (cdddar lis))) (define makeMethodList (lambda (listToMake retList) ;(display listToMake) (cond [(null? listToMake) retList ;(display "The list passed in to parse was null") ] [else (makeMethodList (cdr listToMake) (append retList (list (getMethodLine listToMake)))) ] ) )) ;(trace makeMethodList) ;this works provided you just pass in the function line (define getMethodLine (lambda (functionList) `((eq? (car msg) ,(caar functionList)) ,(caddar functionList)))) (define load-classes (lambda paramList (cond [(null? paramList) (display "Your parameters are null, man.")] [(null? (car paramList))(display "Done creating class definitions.")] [(not (null? (car paramList))) (begin (let* ((className (cadaar paramList)) (classInstanceVars (cdaddr (cddaar paramList))) (classMethodList (cdr (cadddr (cddaar paramList)))) (desiredMethodList (makeMethodList classMethodList '())) ) ;(display "Classname: ") ;(display className) ;(newline)(newline) ;(display "Class Instance Vars: ") ;(display classInstanceVars) ;(newline)(newline) ;(display "Class Method List: ") ;(display classMethodList) ;(newline) ;(display "Desired Method List: ") ;(display desiredMethodList)) ;(newline)(newline) ;---------------------------------------------------- ;do not delete the below code!` `(define ,className (let ,classInstanceVars (lambda msg ;return the function list here (cond ,(makeMethodList classMethodList '()))) )) ;--------------------------------------------------- ))] ) )) (load-classes lis) ;(load-classes lis) ;(load-classes-helper lis) ;(load-classes "simpletest.txt") ;(load-classes "complextest.txt") ;method list ;(display (cdr (cadddr (cddaar <class>))))

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  • Using Apple’s Bonjour service from .NET?

    - by Martín Marconcini
    I have an iPhone app that publishes through Bonjour. The Mac counterpart works, they sync and exchange data. Now I have to port that little Mac app to Windows. I’ve decided to go with .NET (because that’s what I know). The app is not complex, but I’m in the early stages. I need to browse/discover Bonjour services. For this task, I’ve downloaded Mono.Zeroconf and Apple’s latest SDK (which includes a couple of C# Samples). I’m not really pasting code because I’m really copy/pasting the samples. In fact, Mono.Zeroconf has a MZClient.exe that can be used to test “all the API”. My 1st test was -on the same box- open two cmd.exe and launch a MZclient registering a service and on the other, launch it and “discover it”. It doesn’t work. Here’s the server: C:\MZ>MZClient -v -p "_http._tcp 80 mysimpleweb” *** Registering name = 'mysimpleweb', type = '_http._tcp', domain = 'local.' *** Registered name = ‘mysimpleweb’ On the other terminal: c:\MZ>MZClient -v -t "_http._tcp" Creating a ServiceBrowser with the following settings: Interface = 0 (All) Address Protocol = Any Domain = local Registration Type = _http._tcp Resolve Shares = False Hit ^C when you're bored waiting for responses. And that’s it. Nothing happens. I’ve of course tried with different services to no avail. Even played a little bit with that domain thing. Remember this is the same box. I tried on another computer, because this was a VM inside OSX, so I went ahead and tried on a “pure” win XP. Nothing. note: I have Apple Bonjour Service (up and running) and also the Apple SDK (installed later). Given that this didn’t work, I went ahead and decided to try the Apple SDK which has an Interop and a few pre-compiled samples (and its source code). Short story, neither the mDSNBrowser.exe nor the SimpleChat.exe work/see/discover anything. My box is a Win7 under Parallels, but that doesn’t seem to be affecting anything, given that the native XP exhibits the same problems. What am I doing so awfully wrong?

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  • Andorid - Display HTML Formatted String

    - by Soren
    I need an example how to display the strings that I have marked up with simple html into a TextView. I have found "Spanned fromHtml(String source)", but I don't know how to plug it into my java code. Here is my Java: package com.SorenWinslow.TriumphHistory; import android.app.ListActivity; import android.os.Bundle; import android.widget.ArrayAdapter; public class TriumphHistory extends ListActivity { String[] HistoryList; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ArrayAdapter<String> adapter; HistoryList = getResources().getStringArray(R.array.history); adapter = new ArrayAdapter<String> (this,R.layout.historylistlayout,HistoryList); setListAdapter(adapter); } } Here is a sample of history: <?xml version="1.0" encoding="utf-8"?> <resources> <string-array name="history"> <item><b>1883</b><br/>Some stuff happened</item> <item><b>1884</b><br/>Some more stuff happened <i>before</i> the other stuff </item> <resources> Here is my historylistlayout.xml: <?xml version="1.0" encoding="utf-8"?> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/text1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceLarge" android:gravity="center_vertical" android:textColor="#ffffff" android:background="#000050" android:layout_marginTop="5px" android:minHeight="?android:attr/listPreferredItemHeight" android:padding="3px" android:textSize="8pt" android:layout_gravity="top|left"/> And here is my main.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:textColor="#ffffff" android:background="#000080" android:isScrollContainer="true" android:layout_height="fill_parent" android:layout_width="fill_parent" android:scrollbarStyle="insideOverlay"> <ListView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/list" android:layout_width="fill_parent" android:layout_height="wrap_content" android:clickable="true" android:dividerHeight="1px"/> </LinearLayout>

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  • Modeling distribution of performance measurements

    - by peterchen
    How would you mathematically model the distribution of repeated real life performance measurements - "Real life" meaning you are not just looping over the code in question, but it is just a short snippet within a large application running in a typical user scenario? My experience shows that you usually have a peak around the average execution time that can be modeled adequately with a Gaussian distribution. In addition, there's a "long tail" containing outliers - often with a multiple of the average time. (The behavior is understandable considering the factors contributing to first execution penalty). My goal is to model aggregate values that reasonably reflect this, and can be calculated from aggregate values (like for the Gaussian, calculate mu and sigma from N, sum of values and sum of squares). In other terms, number of repetitions is unlimited, but memory and calculation requirements should be minimized. A normal Gaussian distribution can't model the long tail appropriately and will have the average biased strongly even by a very small percentage of outliers. I am looking for ideas, especially if this has been attempted/analysed before. I've checked various distributions models, and I think I could work out something, but my statistics is rusty and I might end up with an overblown solution. Oh, a complete shrink-wrapped solution would be fine, too ;) Other aspects / ideas: Sometimes you get "two humps" distributions, which would be acceptable in my scenario with a single mu/sigma covering both, but ideally would be identified separately. Extrapolating this, another approach would be a "floating probability density calculation" that uses only a limited buffer and adjusts automatically to the range (due to the long tail, bins may not be spaced evenly) - haven't found anything, but with some assumptions about the distribution it should be possible in principle. Why (since it was asked) - For a complex process we need to make guarantees such as "only 0.1% of runs exceed a limit of 3 seconds, and the average processing time is 2.8 seconds". The performance of an isolated piece of code can be very different from a normal run-time environment involving varying levels of disk and network access, background services, scheduled events that occur within a day, etc. This can be solved trivially by accumulating all data. However, to accumulate this data in production, the data produced needs to be limited. For analysis of isolated pieces of code, a gaussian deviation plus first run penalty is ok. That doesn't work anymore for the distributions found above. [edit] I've already got very good answers (and finally - maybe - some time to work on this). I'm starting a bounty to look for more input / ideas.

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  • NSXMLParser Memory Allocation Efficiency for the iPhone

    - by Staros
    Hello, I've recently been playing with code for an iPhone app to parse XML. Sticking to Cocoa, I decided to go with the NSXMLParser class. The app will be responsible for parsing 10,000+ "computers", all which contain 6 other strings of information. For my test, I've verified that the XML is around 900k-1MB in size. My data model is to keep each computer in an NSDictionary hashed by a unique identifier. Each computer is also represented by a NSDictionary with the information. So at the end of the day, I end up with a NSDictionary containing 10k other NSDictionaries. The problem I'm running into isn't about leaking memory or efficient data structure storage. When my parser is done, the total amount of allocated objects only does go up by about 1MB. The problem is that while the NSXMLParser is running, my object allocation is jumping up as much as 13MB. I could understand 2 (one for the object I'm creating and one for the raw NSData) plus a little room to work, but 13 seems a bit high. I can't imaging that NSXMLParser is that inefficient. Thoughts? Code... The code to start parsing... NSXMLParser *parser = [[NSXMLParser alloc] initWithData: data]; [parser setDelegate:dictParser]; [parser parse]; output = [[dictParser returnDictionary] retain]; [parser release]; [dictParser release]; And the parser's delegate code... -(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict { if(mutableString) { [mutableString release]; mutableString = nil; } mutableString = [[NSMutableString alloc] init]; } -(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string { if(self.mutableString) { [self.mutableString appendString:string]; } } -(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName { if([elementName isEqualToString:@"size"]){ //The initial key, tells me how many computers returnDictionary = [[NSMutableDictionary alloc] initWithCapacity:[mutableString intValue]]; } if([elementName isEqualToString:hashBy]){ //The unique identifier if(mutableDictionary){ [mutableDictionary release]; mutableDictionary = nil; } mutableDictionary = [[NSMutableDictionary alloc] initWithCapacity:6]; [returnDictionary setObject:[NSDictionary dictionaryWithDictionary:mutableDictionary] forKey:[NSMutableString stringWithString:mutableString]]; } if([fields containsObject:elementName]){ //Any of the elements from a single computer that I am looking for [mutableDictionary setObject:mutableString forKey:elementName]; } } Everything initialized and released correctly. Again, I'm not getting errors or leaking. Just inefficient. Thanks for any thoughts!

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  • What should I do or don't do to avoid Delphi "push dword" bug.

    - by Maksee
    I found that Delphi 5 generates invalid assembly code in specific cases. I can't understand in what cases in general. The example below produces access violation since a very strange optimization occurs. For a byte in a record or array Delphi generates push dword [...], pop ebx, mov .., bl that works correctly if there are data after this byte (we need at least three to push dword correctly), but fails if the data is inaccessible. I emulated the strict boundaries here with win32 Virtual* functions Specifically the error occurs when the last byte from the block accessed inside FeedBytesToClass procedure. And if I try to change something like using data array instead of object property of remove actionFlag variable, Delphi generates correct assembly instructions. const BlockSize = 4096; type TSomeClass = class private fBytes: PByteArray; public property Bytes: PByteArray read fBytes; constructor Create; destructor Destroy;override; end; constructor TSomeClass.Create; begin inherited Create; GetMem(fBytes, BlockSize); end; destructor TSomeClass.Destroy; begin FreeMem(fBytes); inherited; end; procedure FeedBytesToClass(SrcDataBytes: PByteArray; Count: integer); var j: integer; Ofs: integer; actionFlag: boolean; AClass: TSomeClass; begin AClass:=TSomeClass.Create; try actionFlag:=true; for j:=0 to Count-1 do begin Ofs:=j; if actionFlag then begin AClass.Bytes[Ofs]:=SrcDataBytes[j]; end; end; finally AClass.Free; end; end; procedure TForm31.Button1Click(Sender: TObject); var SrcDataBytes: PByteArray; begin SrcDataBytes:=VirtualAlloc(Nil, BlockSize, MEM_COMMIT, PAGE_READWRITE); try if VirtualLock(SrcDataBytes, BlockSize) then try FeedBytesToClass(SrcDataBytes, BlockSize); finally VirtualUnLock(SrcDataBytes, BlockSize); end; finally VirtualFree(SrcDataBytes, MEM_DECOMMIT, BlockSize); end; end; Initially the error occured when I used access to RGB data of bitmap bits, but the code there is too complex so I narrowed it to this fragment. So the question is what is here so specific that makes Delphi produce push,pop,mov optimization. I need to know this in order to avoid such side effects in general.

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  • Populating ComboBoxDataColumn items and values

    - by MarceloRamires
    I have a "populate combobox", and I'm so happy with it that I've even started using more comboboxes. It takes the combobox object by reference with the ID of the "value set" (or whatever you want to call it) from a table and adds the items and their respective values (which differ) and does the job. I've recently had the brilliant idea of using comboboxes in a gridview, and I was happy to notice that it worked JUST LIKE a single combobox, but populating all the comboboxes in the given column at the same time. ObjComboBox.Items.Add("yadayada"); //works just like ObjComboBoxColumn.Items.Add("blablabla"); But When I started planning how to populate these comboboxes I've noticed: There's no "Values" property in ComboBoxDataColumn. ObjComboBox.Values = whateverArray; //works, but the following doesn't ObjComboBoxColumn.Values = whateverArray; Questions: 0 - How do I populate it's values ? (I suspect it's just as simple, but uses another name) 1 - If it works just like a combobox, what's the explanation for not having this attribute ? -----[EDIT]------ So I've checked out Charles' quote, and I've figured I had to change my way of populating these bad boys. Instead of looping through the strings and inserting them one by one in the combobox, I should grab the fields I want to populate in a table, and set one column of the table as the "value", and other one as the "display". So I've done this: ObjComboBoxColumn.DataSource = DTConfig; //Double checked, guaranteed to be populated ObjComboBoxColumn.ValueMember = "Code"; ObjComboBoxColumn.DisplayMember = "Description"; But nothing happens, if I use the same object as so: ObjComboBoxColumn.Items.Add("StackOverflow"); It is added. There is no DataBind() function. It finds the two columns, and that's guaranteed ("Code" and "Description") and if I change their names to nonexistant ones it gives me an exception, so that's a good sign. -----[EDIT]------ I have a table in SQL Server that is something like code  |  text —————    1    | foo    2    | bar It's simple, and with other comboboxes (outside of gridviews) i've successfully populated looping through the rows and adding the texts: ObjComboBox.Items.Add(MyDataTable.Rows[I]["MyColumnName"].ToString()); And getting every value, adding it into an array, and setting it like: ObjComboBox.Values = MyArray; I'd like to populate my comboboxColumns just as simply as I do with comboboxes.

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  • Validate a string in a table in SQL Server - CLR function or T-SQL (Question updated)

    - by Ashish Gupta
    I need to check If a column value (string) in SQL server table starts with a small letter and can only contain '_', '-', numbers and alphabets. I know I can use a SQL server CLR function for that. However, I am trying to implement that validation using a scalar UDF and could make very little here...I can use 'NOT LIKE', but I am not sure how to make sure I validate the string irrespective of the order of characters or in other words write a pattern in SQL for this. Am I better off using a SQL CLR function? Any help will be appreciated.. Thanks in advance Thank you everyone for their comments. This morning, I chose to go CLR function way. For the purpose of what I was trying to achieve, I created one CLR function which does the validation of an input string and have that called from a SQL UDF and It works well. Just to measure the performance of t-SQL UDF using SQL CLR function vs t- SQL UDF, I created a SQL CLR function which will just check if the input string contains only small letters, it should return true else false and have that called from a UDF (IsLowerCaseCLR). After that I also created a regular t-SQL UDF(IsLowerCaseTSQL) which does the same thing using the 'NOT LIKE'. Then I created a table (Person) with columns Name(varchar) and IsValid(bit) columns and populate that with names to test. Data :- 1000 records with 'Ashish' as value for Name column 1000 records with 'ashish' as value for Name column then I ran the following :- UPDATE Person Set IsValid=1 WHERE dbo.IsLowerCaseTSQL (Name) Above updated 1000 records (with Isvalid=1) and took less than a second. I deleted all the data in the table and repopulated the same with same data. Then updated the same table using Sql CLR UDF (with Isvalid=1) and this took 3 seconds! If update happens for 5000 records, regular UDF takes 0 seconds compared to CLR UDF which takes 16 seconds! I am very less knowledgeable on t-SQL regular expression or I could have tested my actual more complex validation criteria. But I just wanted to know, even I could have written that, would that have been faster than the SQL CLR function considering the example above. Are we using SQL CLR because we can implement we can implement lot richer logic which would have been difficult otherwise If we write in regular SQL. Sorry for this long post. I just want to know from the experts. Please feel free to ask if you could not understand anything here. Thank you again for your time.

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  • help with jquery ajax and templates in asp.net mvc

    - by NachoF
    So I have a complex form for an IncomeDeclaration. Its going to display a textfield GrossIncome for each Activity that the IncomeDeclaration is related to... this all gets done on the server and works just fine.... the problem is. The User should also be able to add Activities on the fly.. through javascript... so when the user clicks on Add Activity a Dropdown and a textfield must be appended to the bottom the activities list... heres what Ive got so far <tbody id="activities"> @Html.EditorFor(model => model.income.EconomicActivityIncomeDeclarations) </tbody> </table> <a href="#" id="add_activity">Agregar Otra Actividad</a> </fieldset> <script type="text/javascript"> $("#add_activity").click(function () { $.getJSON('/IncomeDeclarations/GetEconomicActivities', function (data) { var select = new Select(); var data = new Array(); for (var i = 0; i < data.length; i++) { var option = new Option(data[i]["name"], data[i]["i"]) //should do something here } //should call the template and append to #activities }); }); </script> <script id="template" type="text/x-jquery-tmpl"> <tr> <td><select name="income.EconomicActivityIncomeDeclarations[${SomeNumber}].EconomicActivityId"> ${MyOptions} </select></td> <td><input type="text" name="income.EconomicActivityIncomeDeclarations[${SomeNumber}].GrossIncome" /></td>> </tr> </script> } The name attribute for both the select and the text_field is key for this to work... otherwise modelbinding wont work... I would think that if the SomeNumber variable is set to new Date.GetTime() model Binding should work just fine... I actually dont see the need of ajax for this but thats another topic.. I just havent figured out a way to do this without ajax... right now I want to get the template to work and append the form elements to the bottom of the list.

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  • Wiki-fying a text using LPeg

    - by Stigma
    Long story coming up, but I'll try to keep it brief. I have many pure-text paragraphs which I extract from a system and re-output in wiki format so that the copying of said data is not such an arduous task. This all goes really well, except that there are no automatic references being generated for the 'topics' we have pages for, which end up needing to be added by reading through all the text and adding it in manually by changing Topic to [[Topic]]. First requirement: each topic is only to be made clickable once, which is the first occurrence. Otherwise, it would become a really spammy linkfest, which would detract from readability. To avoid issues with topics that start with the same words Second requirement: overlapping topic names should be handled in such a way that the most 'precise' topic gets the link, and in later occurrences, the less precise topics do not get linked, since they're likely not correct. Example: topics = { "Project", "Mary", "Mr. Moore", "Project Omega"} input = "Mary and Mr. Moore work together on Project Omega. Mr. Moore hates both Mary and Project Omega, but Mary simply loves the Project." output = function_to_be_written(input) -- "[[Mary]] and [[Mr. Moore]] work together on [[Project Omega]]. Mr. Moore hates both Mary and Project Omega, but Mary simply loves the [[Project]]." Now, I quickly figured out a simple or complicated string.gsub() could not get me what I need to satisfy the second requirement, as it provides no way to say 'Consider this match as if it did not happen - I want you to backtrack further'. I need the engine to do something akin to: input = "abc def ghi" -- Looping over the input would, in this order, match the following strings: -- 1) abc def ghi -- 2) abc def -- 3) abc -- 4) def ghi -- 5) def -- 6) ghi Once a string matches an actual topic and has not been replaced before by its wikified version, it is replaced. If this topic has been replaced by a wikified version before, don't replace, but simply continue the matching at the end of the topic. (So for a topic "abc def", it would test "ghi" next in both cases.) Thus I arrive at LPeg. I have read up on it, played with it, but it is considerably complex, and while I think I need to use lpeg.Cmt and lpeg.Cs somehow, I am unable to mix the two properly to make what I want to do work. I am refraining from posting my practice attempts as they are of miserable quality and probably more likely to confuse anyone than assist in clarifying my problem. (Why do I want to use a PEG instead of writing a triple-nested loop myself? Because I don't want to, and it is a great excuse to learn PEGs.. except that I am in over my head a bit. Unless it is not possible with LPeg, the first is not an option.)

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  • Storing a set of criteria in another table

    - by bendataclear
    I have a large table with sales data, useful data below: RowID Date Customer Salesperson Product_Type Manufacturer Quantity Value 1 01-06-2004 James Ian Taps Tap Ltd 200 £850 2 02-06-2004 Apple Fran Hats Hats Inc 30 £350 3 04-06-2004 James Lawrence Pencils ABC Ltd 2000 £980 ... Many rows later... ... 185352 03-09-2012 Apple Ian Washers Tap Ltd 600 £80 I need to calculate a large set of targets from table containing values different types, target table is under my control and so far is like: TargetID Year Month Salesperson Target_Type Quantity 1 2012 7 Ian 1 6000 2 2012 8 James 2 2000 3 2012 9 Ian 2 6500 At present I am working out target types using a view of the first table which has a lot of extra columns: SELECT YEAR(Date) , MONTH(Date) , Salesperson , Quantity , CASE WHEN Manufacturer IN ('Tap Ltd','Hats Inc') AND Product_Type = 'Hats' THEN True ELSE False END AS IsType1 , CASE WHEN Manufacturer = 'Hats Inc' AND Product_Type IN ('Hats','Coats') THEN True ELSE False END AS IsType2 ... ... , CASE WHEN Manufacturer IN ('Tap Ltd','Hats Inc') AND Product_Type = 'Hats' THEN True ELSE False END AS IsType24 , CASE WHEN Manufacturer IN ('Tap Ltd','Hats Inc') AND Product_Type = 'Hats' THEN True ELSE False END AS IsType25 FROM SalesTable WHERE [some stuff here] This is horrible to read/debug and I hate it!! I've tried a few different ways of simplifying this but have been unable to get it to work. The closest I have come is to have a third table holding the definition of the types with the values for each field and the type number, this can be joined to the tables to give me the full values but I can't work out a way to cope with multiple values for each field. Finally the question: Is there a standard way this can be done or an easier/neater method other than one column for each type of target? I know this is a complex problem so if anything is unclear please let me know. Edit - What I need to get: At the very end of the process I need to have targets displayed with actual sales: Type Year Month Salesperson TargetQty ActualQty 2 2012 8 James 2000 2809 2 2012 9 Ian 6500 6251 Each row of the sales table could potentially satisfy 8 of the types. Some more points: I have 5 different columns that need to be defined against the targets (or set to NULL to include any value) I have between 30 and 40 different types that need to be defined, several of the columns could contain as many as 10 different values For point 2, if I am using a row for each permutation of values, 2 columns with 10 values each would give me 100 rows for each sales person for each month which is a lot but if this is the only way to define multiple values I will have to do this. Sorry if this makes no sense!

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  • trouble resolving location in <xs:import > element in C#

    - by BobC
    I'm using an XML schema document to validate incoming data documents, however the schema appears be failing during compilation at run time because it refers to a complex type which part of an external schema. The external schema is specified in a element at the top of the document. I had thought it might be an access problem, so I moved a copy of the external document to a localhost folder. I get the same error, so now I'm wondering if there might be some sort of issue with the use of the element. The schema document fragment looks like this: <xs:schema targetNamespace="http://www.smpte-ra.org/schemas/429-7/2006/CPL" xmlns:cpl="http://www.smpte-ra.org/schemas/429-7/2006/CPL" xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified"> ... <xs:import namespace="http://www.w3.org/2000/09/xmldsig#" schemaLocation="http://localhost/TMSWebServices/XMLSchema/xmldsig-core-schema.xsd"/> ... <xs:element name="Signer" type="ds:KeyInfoType" minOccurs="0"/> ... </xs:schema> The code I'm trying to run this with is real simple (got it from http://dotnetslackers.com/Community/blogs/haissam/archive/2008/11/06/validate-xml-against-xsd-xml-schema-using-c.aspx) string XSDFILEPATH = @"http://localhost/TMSWebServices/XMLSchema/CPL.xsd"; string XMLFILEPATH = @"C:\foo\bar\files\TestCPLs\CPL_930f5e92-be03-440c-a2ff-a13f3f16e1d6.xml"; System.Xml.XmlReaderSettings settings = new System.Xml.XmlReaderSettings(); settings.Schemas.Add(null, XSDFILEPATH); settings.ValidationType = System.Xml.ValidationType.Schema; System.Xml.XmlDocument document = new System.Xml.XmlDocument(); document.Load(XMLFILEPATH); System.Xml.XmlReader rdr = System.Xml.XmlReader.Create(new StringReader(document.InnerXml), settings); while (rdr.Read()) { } Everything goes well until the line that instantiates the XMLReader object just before the while loop. Then it fails with a type not declared error. The type that it's trying to find, KeyInfoType, is defined in one of the the documents in the import element. I've made sure the namespaces line up. I wondered if the # signs in the namespace definitions were causing a problem, but removing them had no effect, it just changed what the error looked like (i.e. "Type 'http://www.w3.org/2000/09/xmldsig:KeyInfoType' is not declared." versus "Type 'http://www.w3.org/2000/09/xmldsig#:KeyInfoType' is not declared.") My suspicion is that there's something about the processing of the element that I'm missing. Any suggestions are very welcome. Thanks!

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  • Data denormalization and C# objects DB serialization

    - by Robert Koritnik
    I'm using a DB table with various different entities. This means that I can't have an arbitrary number of fields in it to save all kinds of different entities. I want instead save just the most important fields (dates, reference IDs - kind of foreign key to various other tables, most important text fields etc.) and an additional text field where I'd like to store more complete object data. the most obvious solution would be to use XML strings and store those. The second most obvious choice would be JSON, that usually shorter and probably also faster to serialize/deserialize... And is probably also faster. But is it really? My objects also wouldn't need to be strictly serializable, because JsonSerializer is usually able to serialize anything. Even anonymous objects, that may as well be used here. What would be the most optimal solution to solve this problem? Additional info My DB is highly normalised and I'm using Entity Framework, but for the purpose of having external super-fast fulltext search functionality I'm sacrificing a bit DB denormalisation. Just for the info I'm using SphinxSE on top of MySql. Sphinx would return row IDs that I would use to fast query my index optimised conglomerate table to get most important data from it much much faster than querying multiple tables all over my DB. My table would have columns like: RowID (auto increment) EntityID (of the actual entity - but not directly related because this would have to point to different tables) EntityType (so I would be able to get the actual entity if needed) DateAdded (record timestamp when it's been added into this table) Title Metadata (serialized data related to particular entity type) This table would be indexed with SPHINX indexer. When I would search for data using this indexer I would provide a series of EntityIDs and a limit date. Indexer would have to return a very limited paged amount of RowIDs ordered by DateAdded (descending). I would then just join these RowIDs to my table and get relevant results. So this won't actually be full text search but a filtering search. Getting RowIDs would be very fast this way and getting results back from the table would be much faster than comparing EntityIDs and DateAdded comparisons even though they would be properly indexed.

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  • Linq-to-sql Compiled Query returning object NOT belonging to submitted DataContext

    - by Vladimir Kojic
    Compiled query: public static class Machines { public static readonly Func<OperationalDataContext, short, Machine> QueryMachineById = CompiledQuery.Compile((OperationalDataContext db, short machineID) => db.Machines.Where(m => m.MachineID == machineID).SingleOrDefault() ); public static Machine GetMachineById(IUnitOfWork unitOfWork, short id) { Machine machine; // Old code (working) //var machineRepository = unitOfWork.GetRepository<Machine>(); //machine = machineRepository.Find(m => m.MachineID == id).SingleOrDefault(); // New code (making problems) machine = QueryMachineById(unitOfWork.DataContext, id); return machine; } It looks like compiled query is caching Machine object and returning the same object even if query is called from new DataContext (I’m disposing DataContext in the service but I’m getting Machine from previous DataContext). I use POCOs and XML mapping. Revised: It looks like compiled query is returning result from new data context and it is not using the one that I passed in compiled-query. Therefore I can not reuse returned object and link it to another object obtained from datacontext thru non compiled queries. [TestMethod] public void GetMachinesTest() { // Test Preparation (not important) using (var unitOfWork = IoC.Get<IUnitOfWork>()) { var machineRepository = unitOfWork.GetRepository<Machine>(); // GET ALL List<Machine> list = machineRepository.FindAll().ToList<Machine>(); VerifyIntegratedMachine(list[2], 3, "Machine 3", "333333", "G300PET", "MachineIconC.xaml", false, true, LicenseType.Licensed, "10.0.97.3", "10.0.97.3", 0); var machine = Machines.GetMachineById(unitOfWork, 3); Assert.AreSame(list[2], machine); // PASS !!!! } using (var unitOfWork = IoC.Get<IUnitOfWork>()) { var machineRepository = unitOfWork.GetRepository<Machine>(); // GET ALL List<Machine> list = machineRepository.FindAll().ToList<Machine>(); VerifyIntegratedMachine(list[2], 3, "Machine 3", "333333", "G300PET", "MachineIconC.xaml", false, true, LicenseType.Licensed, "10.0.97.3", "10.0.97.3", 0); var machine = Machines.GetMachineById(unitOfWork, 3); Assert.AreSame(list[2], machine); // FAIL !!!! } } If I run other (complex) unit tests I'm getting as expected: An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext.

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  • KISS: Simple C# application which communicates with a RESTful web service.

    - by Workshop Alex
    Following the KISS principle, I suddenly realised the following: In .NET, you can use the Entity Model Framework to wrap around a database. This model can be exposed as a web service through WCF. This web service would have a very standardized definition. A client application could be created which could consume any such RESTful web service. I don't want to re-invent the wheel and it wouldn't surprise me if someone has already done this, so my question is simple: Has anyone already created a simple (desktop, not web) client application that can consume a RESTful service that's based on the Entity Framework and which will allow the user to read and write data directly to this service? Otherwise, I'll just have to "invent" this myself. :-)Problem is, the database layer and RESTful service is already finished. The RESTful service will only stay in the project during it's development phase, since we can use the database-layer assembly directly from the web applications that are build around it. When the web application is deployed, the RESTful services are just kept out of the deployment. But the database has a lot of data to manage over nearly 50 tables. When developing against a local database, we can have straight access to the database so I wouldn't need this tool for this. When it's deployed, the web application would be the only way to access the data so I could not use this tool. But we're also having a test phase where the database is stored on another system outside the local domain and this database is not available for developers. Only administrators have direct access to this database, making tests a bit more complex. However, through the RESTful service, I can still access the data directly. Thus, when some test goes wrong, I can repair the data through this connection or just create a copy of the data for tests on my local system. There's plenty of other functionality and it's even possible to just open the URL to a table service straight in Excel or XMLSpy to see the contents. But when I want to write something back, I have to write special code to do just that. A generic tool that would allow me to access the data and modify it would be easier. Since it's a generic setup around the ADO.NET Data services, this should be reasonable easy too. Thus, I can do it but hoped someone else has already done something similar. But it appears that there's no such tool made yet...

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  • Sharing a file from Android to Gmail or to Dropbox

    - by Calaf
    To share a simple text file, I started by copying verbatim from FileProvider's manual page: <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <provider android:name="android.support.v4.content.FileProvider" android:authorities="com.mycorp.helloworldtxtfileprovider.MainActivity" android:exported="false" android:grantUriPermissions="true" > <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/my_paths" /> </provider> <activity android:name="com.mycorp.helloworldtxtfileprovider.MainActivity" ... Then I saved a text file and used, again nearly verbatim, the code under Sending binary content. (Notice that this applies more accurately in this case than "Sending text content" since we are sending a file, which happens to be a text file, rather than just a string of text.) For the convenience of duplication on your side, and since the code is in any case so brief, I'm including it here in full. public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); String filename = "hellow.txt"; String fileContents = "Hello, World!\n"; byte[] bytes = fileContents.getBytes(); FileOutputStream fos = null; try { fos = this.openFileOutput(filename, MODE_PRIVATE); fos.write(bytes); } catch (IOException e) { e.printStackTrace(); } finally { try { fos.close(); } catch (IOException e) { e.printStackTrace(); } } File file = new File(filename); Intent shareIntent = new Intent(); shareIntent.setAction(Intent.ACTION_SEND); shareIntent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(file)); shareIntent.setType("application/txt"); startActivity(Intent.createChooser(shareIntent, getResources().getText(R.string.send_to))); file.delete(); } } Aside from adding a value for send_to in res/values/strings.xml, the only other change I did to the generic Hello, World that Eclipse creates is to add the following in res/xml/my_paths.xml (as described on the page previously referenced. <paths xmlns:android="http://schemas.android.com/apk/res/android"> <Files-path name="files" path="." /> </paths> This code runs fine. It shows a list of intent recipients. But sending the text file to either Dropbox or to Gmail fails. Dropbox sends the notification "Uploading to Dropbox" followed by "Upload failed: my_file.txt". After "sending message.." Gmail sends "Couldn't send attachment". What is wrong?

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  • How to create a Uri instance parsed with GenericUriParserOptions.DontCompressPath

    - by Andrew Arnott
    When the .NET System.Uri class parses strings it performs some normalization on the input, such as lower-casing the scheme and hostname. It also trims trailing periods from each path segment. This latter feature is fatal to OpenID applications because some OpenIDs (like those issued from Yahoo) include base64 encoded path segments which may end with a period. How can I disable this period-trimming behavior of the Uri class? Registering my own scheme using UriParser.Register with a parser initialized with GenericUriParserOptions.DontCompressPath avoids the period trimming, and some other operations that are also undesirable for OpenID. But I cannot register a new parser for existing schemes like HTTP and HTTPS, which I must do for OpenIDs. Another approach I tried was registering my own new scheme, and programming the custom parser to change the scheme back to the standard HTTP(s) schemes as part of parsing: public class MyUriParser : GenericUriParser { private string actualScheme; public MyUriParser(string actualScheme) : base(GenericUriParserOptions.DontCompressPath) { this.actualScheme = actualScheme.ToLowerInvariant(); } protected override string GetComponents(Uri uri, UriComponents components, UriFormat format) { string result = base.GetComponents(uri, components, format); // Substitute our actual desired scheme in the string if it's in there. if ((components & UriComponents.Scheme) != 0) { string registeredScheme = base.GetComponents(uri, UriComponents.Scheme, format); result = this.actualScheme + result.Substring(registeredScheme.Length); } return result; } } class Program { static void Main(string[] args) { UriParser.Register(new MyUriParser("http"), "httpx", 80); UriParser.Register(new MyUriParser("https"), "httpsx", 443); Uri z = new Uri("httpsx://me.yahoo.com/b./c.#adf"); var req = (HttpWebRequest)WebRequest.Create(z); req.GetResponse(); } } This actually almost works. The Uri instance reports https instead of httpsx everywhere -- except the Uri.Scheme property itself. That's a problem when you pass this Uri instance to the HttpWebRequest to send a request to this address. Apparently it checks the Scheme property and doesn't recognize it as 'https' because it just sends plaintext to the 443 port instead of SSL. I'm happy for any solution that: Preserves trailing periods in path segments in Uri.Path Includes these periods in outgoing HTTP requests. Ideally works with under ASP.NET medium trust (but not absolutely necessary).

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  • Is the design notion of layers contrived?

    - by Bruce
    Hi all I'm reading through Eric Evans' awesome work, Domain-Driven Design. However, I can't help feeling that the 'layers' model is contrived. To expand on that statement, it seems as if it tries to shoe-horn various concepts into a specific, neat model, that of layers talking to each other. It seems to me that the layers model is too simplified to actually capture the way that (good) software works. To expand further: Evans says: "Partition a complex program into layers. Develop a design within each layer that is cohesive and that depends only on the layers below. Follow standard architectural patterns to provide loose coupling to the layers above." Maybe I'm misunderstanding what 'depends' means, but as far as I can see, it can either mean a) Class X (in the UI for example) has a reference to a concrete class Y (in the main application) or b) Class X has a reference to a class Y-ish object providing class Y-ish services (ie a reference held as an interface). If it means (a), then this is clearly a bad thing, since it defeats re-using the UI as a front-end to some other application that provides Y-ish functionality. But if it means (b), then how is the UI any more dependent on the application, than the application is dependent on the UI? Both are decoupled from each other as much as they can be while still talking to each other. Evans' layer model of dependencies going one way seems too neat. First, isn't it more accurate to say that each area of the design provides a module that is pretty much an island to itself, and that ideally all communication is through interfaces, in a contract-driven/responsibility-driven paradigm? (ie, the 'dependency only on lower layers' is contrived). Likewise with the domain layer talking to the database - the domain layer is as decoupled (through DAO etc) from the database as the database is from the domain layer. Neither is dependent on the other, both can be swapped out. Second, the idea of a conceptual straight line (as in from one layer to the next) is artificial - isn't there more a network of intercommunicating but separate modules, including external services, utility services and so on, branching off at different angles? Thanks all - hoping that your responses can clarify my understanding on this..

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  • System architecture: simple approach for setting up background tasks behind a web application -- wil

    - by Tim Molendijk
    I have a Django web application and I have some tasks that should operate (or actually: be initiated) on the background. The application is deployed as follows: apache2-mpm-worker; mod_wsgi in daemon mode (1 process, 15 threads). The background tasks have the following characteristics: they need to operate in a regular interval (every 5 minutes or so); they require the application context (i.e. the application packages need to be available in memory); they do not need any input other than database access, in order to perform some not-so-heavy tasks such as sending out e-mail and updating the state of the database. Now I was thinking that the most simple approach to this problem would be simply to piggyback on the existing application process (as spawned by mod_wsgi). By implementing the task as part of the application and providing an HTTP interface for it, I would prevent the overhead of another process that is holding all of the application into memory. A simple cronjob can be setup that sends a request to this HTTP interface every 5 minutes and that would be it. Since the application process provides 15 threads and the tasks are quite lightweight and only running every 5 minutes, I figure they would not be hindering the performance of the web application's user-facing operations. Yet... I have done some online research and I have seen nobody advocating this approach. Many articles suggest a significantly more complex approach based on a full-blown messaging component (such as Celery, which uses RabbitMQ). Although that's sexy, it sounds like overkill to me. Some articles suggest setting up a cronjob that executes a script which performs the tasks. But that doesn't feel very attractive either, as it results in creating a new process that loads the entire application into memory, performs some tiny task, and destroys the process again. And this is repeated every 5 minutes. Does not sound like an elegant solution. So, I'm looking for some feedback on my suggested approach as described in the paragraph before the preceeding paragraph. Is my reasoning correct? Am I overlooking (potential) problems? What about my assumption that application's performance will not be impeded?

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  • Merging two XML files into one XML file using Java

    - by dmurali
    I am stuck with how to proceed with combining two different XML files(which has the same structure). When I was doing some research on it, people say that XML parsers like DOM or StAX will have to be used. But cant I do it with the regular IOStream? I am currently trying to do with the help of IOStream but this is not solving my purpose, its being more complex. For example, What I have tried is; public class GUI { public static void main(String[] args) throws Exception { // Creates file to write to Writer output = null; output = new BufferedWriter(new FileWriter("C:\\merged.xml")); String newline = System.getProperty("line.separator"); output.write(""); // Read in xml file 1 FileInputStream in = new FileInputStream("C:\\1.xml"); BufferedReader br = new BufferedReader(new InputStreamReader(in)); String strLine; while ((strLine = br.readLine()) != null) { if (strLine.contains("<MemoryDump>")){ strLine = strLine.replace("<MemoryDump>", "xmlns:xsi"); } if (strLine.contains("</MemoryDump>")){ strLine = strLine.replace("</MemoryDump>", "xmlns:xsd"); } output.write(newline); output.write(strLine); System.out.println(strLine); } // Read in xml file 2 FileInputStream in = new FileInputStream("C:\\2.xml"); BufferedReader br1 = new BufferedReader(new InputStreamReader(in)); String strLine1; while ((strLine1 = br1.readLine()) != null) { if (strLine1.contains("<MemoryDump>")){ strLine1 = strLine1.replace("<MemoryDump>", ""); } if (strLine1.contains("</MemoryDump>")){ strLine1 = strLine1.replace("</MemoryDump>", ""); } output.write(newline); output.write(strLine1); I request you to kindly let me know how do I proceed with merging two XML files by adding additional content as well. It would be great if you could provide me some example links as well..! Thank You in Advance..! System.out.println(strLine1); } }

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  • .NET asmx web services: serialize object property as string property to support versioning

    - by mcliedtk
    I am in the process of upgrading our web services to support versioning. We will be publishing our versioned web services like so: http://localhost/project/services/1.0/service.asmx http://localhost/project/services/1.1/service.asmx One requirement of this versioning is that I am not allowed to break the original wsdl (the 1.0 wsdl). The challenge lies in how to shepherd the newly versioned classes through the logic that lies behind the web services (this logic includes a number of command and adapter classes). Note that upgrading to WCF is not an option at the moment. To illustrate this, let's consider an example with Blogs and Posts. Prior to the introduction of versions, we were passing concrete objects around instead of interfaces. So an AddPostToBlog command would take in a Post object instead of an IPost. // Old AddPostToBlog constructor. public AddPostToBlog(Blog blog, Post post) { // constructor body } With the introduction of versioning, I would like to maintain the original Post while adding a PostOnePointOne. Both Post and PostOnePointOne will implement the IPost interface (they are not extending an abstract class because that inheritance breaks the wsdl, though I suppose there may be a way around that via some fancy xml serialization tricks). // New AddPostToBlog constructor. public AddPostToBlog(Blog blog, IPost post) { // constructor body } This brings us to my question regarding serialization. The original Post class has an enum property named Type. For various cross-platform compatibility issues, we are changing our enums in our web services to strings. So I would like to do the following: // New IPost interface. public interface IPost { object Type { get; set; } } // Original Post object. public Post { // The purpose of this attribute would be to maintain how // the enum currently is serialized even though now the // type is an object instead of an enum (internally the // object actually is an enum here, but it is exposed as // an object to implement the interface). [XmlMagic(SerializeAsEnum)] object Type { get; set; } } // New version of Post object public PostOnePointOne { // The purpose of this attribute would be to force // serialization as a string even though it is an object. [XmlMagic(SerializeAsString)] object Type { get; set; } } The XmlMagic refers to an XmlAttribute or some other part of the System.Xml namespace that would allow me to control the type of the object property being serialized (depending on which version of the object I am serializaing). Does anyone know how to accomplish this?

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  • Can LINQ-to-SQL omit unspecified columns on insert so a database default value is used?

    - by Todd Ropog
    I have a non-nullable database column which has a default value set. When inserting a row, sometimes a value is specified for the column, sometimes one is not. This works fine in TSQL when the column is omitted. For example, given the following table: CREATE TABLE [dbo].[Table1]( [id] [int] IDENTITY(1,1) NOT NULL, [col1] [nvarchar](50) NOT NULL, [col2] [nvarchar](50) NULL, CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED ([id] ASC) ) GO ALTER TABLE [dbo].[Table1] ADD CONSTRAINT [DF_Table1_col1] DEFAULT ('DB default') FOR [col1] The following two statements will work: INSERT INTO Table1 (col1, col2) VALUES ('test value', '') INSERT INTO Table1 (col2) VALUES ('') In the second statement, the default value is used for col1. The problem I have is when using LINQ-to-SQL (L2S) with a table like this. I want to produce the same behavior, but I can't figure out how to make L2S do that. I want to be able to run the following code and have the first row get the value I specify and the second row get the default value from the database: var context = new DataClasses1DataContext(); var row1 = new Table1 { col1 = "test value", col2 = "" }; context.Table1s.InsertOnSubmit(row1); context.SubmitChanges(); var row2 = new Table1 { col2 = "" }; context.Table1s.InsertOnSubmit(row2); context.SubmitChanges(); If the Auto Generated Value property of col1 is False, the first row is created as desired, but the second row fails with a null error on col1. If Auto Generated Value is True, both rows are created with the default value from the database. I've tried various combinations of Auto Generated Value, Auto-Sync and Nullable, but nothing I've tried gives the behavior I want. L2S does not omit the column from the insert statement when no value is specified. Instead it does something like this: INSERT INTO Table1 (col1, col2) VALUES (null, '') ...which of course causes a null error on col1. Is there some way to get L2S to omit a column from the insert statement if no value is given? Or is there some other way to get the behavior I want? I need the default value at the database level because not all row inserts are done via L2S, and in some cases the default value is a little more complex than a hard coded value (e.g. creating the default based on another field) so I'd rather avoid duplicating that logic.

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  • Creating meaningful routes in wizard style ASP.NET MVC form

    - by R0MANARMY
    I apologize in advance for a long question, figured better have a bit more information than not enough. I'm working on an application with a fairly complex form (~100 fields on it). In order to make the UI a little more presentable the fields are organized into regions and split across multiple (~10) tabs (not unlike this, but each tab does a submit/redirect to next tab). This large input form can also be in one of 3 views (read only, editable, print friendly). The form represents a large domain object (let's call it Foo). I have a controller for said domain object (FooController). It makes sense to me to have the controller be responsible for all the CRUD related operations. Here are the problems I'm having trouble figuring out. Goals: I'd like to keep to conventions so that Foo/Create creates a new record Foo/Delete deletes a record Foo/Edit/{foo_id} takes you to the first tab of the form ...etc I'd like to be able to not repeat the data access code such that I can have Foo/Edit/{foo_id}/tab1 Foo/View/{foo_id}/tab1 Foo/Print/{foo_id}tab1 ...etc use the same data access code to get the data and just specify which view to use to render it. My current implementation has a massive FooController with Create, Delete, Tab1, Tab2, etc actions. Tab actions are split out into separate files for organization (using partial classes, which may or may not be abuse of partial classes). Problem I'm running into is how to organize my controller(s) and routes to make that happen. I have the default route {controller}/{action}/{id} Which handles goal 1 properly but doesn't quite play nice with goal 2. I tried to address goal 2 by defining extra routes like so: routes.MapRoute( "FooEdit", "Foo/Edit/{id}/{action}", new { controller = "Foo", action = "Tab1", mode = "Edit", id = (string)null } ); routes.MapRoute( "FooView", "Foo/View/{id}/{action}", new { controller = "Foo", action = "Tab1", mode = "View", id = (string)null } ); routes.MapRoute( "FooPrint", "Foo/Print/{id}/{action}", new { controller = "Foo", action = "Tab1", mode = "Print", id = (string)null } ); However defining these extra routes causes the Url.Action to generate routs like Foo/Edit/Create instead of Foo/Create. That leads me to believe I designed something very very wrong, but this is my first attempt an asp.net mvc project and I don't know any better. Any advice with this particular situation would be awesome, but feedback on design in similar projects is welcome.

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