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• How can I stop an auto-generated Linq to SQL class from loading ALL data?

  - by Gary McGill

  I have an ASP.NET MVC project, much like the NerdDinner tutorial example. (I'm using MVC 2, but followed the NerdDinner tutorial in order to create it). As per the instructions in part 3 of the tutorial, I've created a Linq-to-SQL model of my database by creating a "Linq to SQL Classes" (.dbml) surface, and dropping my database tables onto it. The designer has automatically added relationships between the generated classes based on my database tables. Let's say that my classes are as per the NerdDinner example, so I have Dinner and RSVP tables, where each Dinner record is associated with many RSVP records - hence in the generated classes, the Dinner object has a RSVPs property which is a list of RSVP objects. My problem is this: it appears (and I'd be gladly proved wrong on this) that as soon as I access a Dinner object, it's loading all of the corresponding RSVP objects, even if I don't use the RSVPs member. First question: is this really the default behavior for the generated classes? In my particular situation, the object graph contains many more tables (which have an order of magnitude more records), and so this is disastrous behaviour - I'd be loading tons of data when all I want to do is show the details of a single parent record. Second question: are there any properties exposed through the designer UI that would let me modify this behavior? (I can't find any). Third question: I've seen a description of how to control the loading of related records in a DataContext by using a DataShape object associated with the DataContext. Is that what I'm meant to do, and if so are there any tutorials like the NerdDinner one that would show not only how to do it, but also suggest a 'pattern' for normal use?

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• PDO/Oracle vs OCI

  - by jarcoal

  The company I work for currently uses some basic functions to abstract the OCI libraries as a means for DB connectivity. We're considering switching to PHP's PDO object, but from some quick searches, it looks like the Oracle driver is a bit less mature than the other PDO drivers. I would appreciate some pro/cons for PDO/Oracle from anyone who has used it in a production environment. Thanks!

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• Using Apple autorelease pools without Objective-C

  - by PierreBdR

  I am developing an application that needs to work on Linux, Windows and Mac OS X. To that purpose, I am using C++ with Qt. For many reasons, on Mac OS X, I need to use CoreFoundation functions (such as CFBundleCopyBundleURL) that creates core objects that need to be released with CFRelease. But doing so generate a lots of these warnings: *** __NSAutoreleaseNoPool(): Object 0x224f7e0 of class NSURL autoreleased with no pool in place - just leaking All the code I've seen concerning these autorelease pools are written in Objective-C. Does anybody know how to create/use autorelease pools in C or C++?

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• Evaluation of CTEs in SQL Server 2005

  - by Jammer

  I have a question about how MS SQL evaluates functions inside CTEs. A couple of searches didn't turn up any results related to this issue, but I apologize if this is common knowledge and I'm just behind the curve. It wouldn't be the first time :-) This query is a simplified (and obviously less dynamic) version of what I'm actually doing, but it does exhibit the problem I'm experiencing. It looks like this: CREATE TABLE #EmployeePool(EmployeeID int, EmployeeRank int); INSERT INTO #EmployeePool(EmployeeID, EmployeeRank) SELECT 42, 1 UNION ALL SELECT 43, 2; DECLARE @NumEmployees int; SELECT @NumEmployees = COUNT(*) FROM #EmployeePool; WITH RandomizedCustomers AS ( SELECT CAST(c.Criteria AS int) AS CustomerID, dbo.fnUtil_Random(@NumEmployees) AS RandomRank FROM dbo.fnUtil_ParseCriteria(@CustomerIDs, 'int') c) SELECT rc.CustomerID, ep.EmployeeID FROM RandomizedCustomers rc JOIN #EmployeePool ep ON ep.EmployeeRank = rc.RandomRank; DROP TABLE #EmployeePool; The following can be assumed about all executions of the above: The result of dbo.fnUtil_Random() is always an int value greater than zero and less than or equal to the argument passed in. Since it's being called above with @NumEmployees which has the value 2, this function always evaluates to 1 or 2. The result of dbo.fnUtil_ParseCriteria(@CustomerIDs, 'int') produces a one-column, one-row table that contains a sql_variant with a base type of 'int' that has the value 219935. Given the above assumptions, it makes sense (to me, anyway) that the result of the expression above should always produce a two-column table containing one record - CustomerID and an EmployeeID. The CustomerID should always be the int value 219935, and the EmployeeID should be either 42 or 43. However, this is not always the case. Sometimes I get the expected single record. Other times I get two records (one for each EmployeeID), and still others I get no records. However, if I replace the RandomizedCustomers CTE with a true temp table, the problem vanishes completely. Every time I think I have an explanation for this behavior, it turns out to not make sense or be impossible, so I literally cannot explain why this would happen. Since the problem does not happen when I replace the CTE with a temp table, I can only assume it has something to do with the functions inside CTEs are evaluated during joins to that CTE. Do any of you have any theories?

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• How to use SQLAlchemy to dump an SQL file from query expressions to bulk-insert into a DBMS?

  - by Mahmoud Abdelkader

  Please bear with me as I explain the problem, how I tried to solve it, and my question on how to improve it is at the end. I have a 100,000 line csv file from an offline batch job and I needed to insert it into the database as its proper models. Ordinarily, if this is a fairly straight-forward load, this can be trivially loaded by just munging the CSV file to fit a schema, but I had to do some external processing that requires querying and it's just much more convenient to use SQLAlchemy to generate the data I want. The data I want here is 3 models that represent 3 pre-exiting tables in the database and each subsequent model depends on the previous model. For example: Model C --> Foreign Key --> Model B --> Foreign Key --> Model A So, the models must be inserted in the order A, B, and C. I came up with a producer/consumer approach: - instantiate a multiprocessing.Process which contains a threadpool of 50 persister threads that have a threadlocal connection to a database - read a line from the file using the csv DictReader - enqueue the dictionary to the process, where each thread creates the appropriate models by querying the right values and each thread persists the models in the appropriate order This was faster than a non-threaded read/persist but it is way slower than bulk-loading a file into the database. The job finished persisting after about 45 minutes. For fun, I decided to write it in SQL statements, it took 5 minutes. Writing the SQL statements took me a couple of hours, though. So my question is, could I have used a faster method to insert rows using SQLAlchemy? As I understand it, SQLAlchemy is not designed for bulk insert operations, so this is less than ideal. This follows to my question, is there a way to generate the SQL statements using SQLAlchemy, throw them in a file, and then just use a bulk-load into the database? I know about str(model_object) but it does not show the interpolated values. I would appreciate any guidance for how to do this faster. Thanks!

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• Math algorithm question

  - by Senica Gonzalez

  I'm not sure if this can be done without some determining factor....but wanted to see if someone knew of a way to do this. I want to create a shifting scale for numbers. Let's say I have the number 26000. I want the outcome of this algorithm to be 6500; or 25% of the original number. But if I have the number 5000, I want the outcome to be 2500; or 50% of the original number. The percentages don't have to be exact, this is just an example. I just want to have like a sine wave sort of thing. As the input number gets higher, the output number is a lower percentage of the input. Does that make sense?

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• Algorithm to fill slots

  - by Peter Lang

  I am searching for an algorithm to fill several slots, which are already filled to some level. The current levels and the available quantity to fill are known Resulting levels should be as equal as possible, but existing level cannot be reduced Slots are filled from left to right, so left slots get higher level if equal level is impossible       The image above shows six examples, each column represents a slot. The grey area is already filled, the blue are is the expected position of the new elements. I could iterate through my slots and increase the quantity on the lowest slot by 1 until the available quantity is consumed, but I wonder about how to actually calculate the new filling levels. I am going to implement this with SQL/PL/SQL, other code is just as welcome though :)

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• How one extends JNA interface mappings? (Java)

  - by rukoche

  User32 interface (platform library) is missing some WinAPI functions, so I tried extending it: package myapp import com.sun.jna.platform.win32.W32API public interface User32 extends com.sun.jna.platform.win32.User32 { myapp.User32 INSTANCE boolean IsWindow(W32API.HWND hWnd) } But then calling myapp.User32.INSTANCE.FindWindow(..) results in java.lang.NullPointerException: Cannot invoke method FindWindow() on null object

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• Converting a HTML string to normal text using iphone dev

  - by user315252

  how to convert a HTML string to a plain text in iphone dev. Is there any in built functions which does it ? I am actually downloading a html string from web and showing it in the UIwebview and i am giving the user a edit option so that the html needs to converted to tet so that user can edit Thanks...

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• function overloading in C

  - by FL4SOF

  Is there any way to achieve function overloading in C? I am looking at simple functions to be overloaded like foo (int a) foo (char b) foo (float c , int d) I think there is no straight forward way, looking for workarounds if any?

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• [.NET] Line break in ListView work in Vista/7 but not in XP

  - by karol

  hi, I've got problem. I'm using ListView to show some data and I need to make two lines in one row. I've found solution to make row higher by adding ImageList with specified height and then I add Environment.NewLine to my text. It works in Vista and 7 but in XP instead of new line there are shown squares. I've been trying to add "\n" "\r\n" and ASCII char 10 but ther were still squares! After few days I still don't know what's wrong and I need your help.

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• With Apache/mod_wsgi how can I redirect to ssl and require Auth?

  - by justin

  I have a Media Temple DV server hosting dev.example.com with django mounted at /. There is a legacy directory in my httpdocs I need to continue to serve at /legacy. But for this directory I need to redirect anyone coming over http over to https, then prompt for http basic auth. In the virtual host conf, I'm pointing the root to a django application: WSGIScriptAlias / /var/django-projects/myproject/apache/django.wsgi <Directory /var/django-projects/myproject/apache> Order allow,deny Allow from all </Directory> Then I alias the legacy directory. Alias /legacy/ /var/www/vhosts/example.com/subdomains/dev/httpdocs/legacy/ <Directory /var/www/vhosts/example.com/subdomains/dev/httpdocs> Order deny,allow Allow from all RewriteEngine On RewriteCond %{SERVER_PORT} 80 RewriteRule ^(.*)$ https://dev.example.com/$1 [R,L] </Directory> This works. It isn't served by django, and the url redirects to https. However, it serves httpdocs/legacy instead of httpsdocs/legacy (where I have an .htaccess that prompts for auth.) Any idea of how I can manage this?

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• Storing third-party libraries in source control

  - by graham.reeds

  Should libraries that the application relies on be stored in source control? One part of me says it should and another part say's no. It feels wrong to add a 20mb library that dwarfs the entire app just because you rely on a couple of functions from it (albeit rather heavily). Should you just store the jar/dll or maybe even the distributed zip/tar of the project? What do other people do?

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• Model relationships in ASP.NET MVC

  - by Fabiano

  Hi I recently started evaluating ASP.NET MVC. While it is really easy and quick to create Controllers and Views for Models with only primitive properties (like shown in the starter videos from the official page) I didn't find any good way to work with references to complex types. Let's say, I have these Models: public class Customer { public int Id { get; set; } public string Name { get; set; } public Address Address { get; set; } public IList<Order> Orders { get; set; } } public class Address { public int Id { get; set; } public string ..... ..... } public class Order { public int Id { get; set; } public Customer Customer { get; set; } public string OrderName { get; set; } ..... } Note that I don't have foreign keys in the models (like it's typical for LINQ to SQL, which is also used in the sample video) but an object reference. How can I handle such references in asp.net mvc? Does someone has some good tips or links to tutorials about this problem? maybe including autobinding with complex types.

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• How do we greatly optimize our MySQL database (or replace it) when using joins?

  - by jkaz

  Hi there, This is the first time I'm approaching an extremely high-volume situation. This is an ad server based on MySQL. However, the query that is used incorporates a lot of JOINs and is generally just slow. (This is Rails ActiveRecord, btw) sel = Ads.find(:all, :select = '*', :joins = "JOIN campaigns ON ads.campaign_id = campaigns.id JOIN users ON campaigns.user_id = users.id LEFT JOIN countries ON countries.campaign_id = campaigns.id LEFT JOIN keywords ON keywords.campaign_id = campaigns.id", :conditions = [flashstr + "keywords.word = ? AND ads.format = ? AND campaigns.cenabled = 1 AND (countries.country IS NULL OR countries.country = ?) AND ads.enabled = 1 AND campaigns.dailyenabled = 1 AND users.uenabled = 1", kw, format, viewer['country'][0]], :order = order, :limit = limit) My questions: Is there an alternative database like MySQL that has JOIN support, but is much faster? (I know there's Postgre, still evaluating it.) Otherwise, would firing up a MySQL instance, loading a local database into memory and re-loading that every 5 minutes help? Otherwise, is there any way I could switch this entire operation to Redis or Cassandra, and somehow change the JOIN behavior to match the (non-JOIN-able) nature of NoSQL? Thank you!

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• Last matching symbol in Regex

  - by Menda

  I couldn't find a more descriptive title, but here there is an example: import re m = re.search(r"\((?P<remixer>.+) (Remix)\)", "Title (Menda Remix)") m.group("remixer") # returns 'Menda' OK m = re.search(r"\((?P<remixer>.+) (Remix)\)", "Title (Blabla) (Menda Remix)") m.group("remixer") # returns 'Blabla) (Menda' FAIL This regex finds the first parenthesis, and I would like to match the last parenthesis for always getting 'Menda'. I've made a workaround to this using extra functions, but I would like a cleaner and a more consistent way using the same regex. Thanks a lot guys.

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• Sorting shell items like windows explorer

  - by Roy M Klever

  Hi, I am making a bread crumb bar in Delphi and having some problems regarding sorting the dropdown of the bread crumbs. Strangely enough, even Vista is not consequent when showing these items. I have tried many ways to figure out what is system folders, what is zip files and what is normal folders. It seems like an easy task but so far I have not found any good way of doing it. One way is to use TypeDisplayName from TSHFileinfo but these are localized names so I can not be sure they will be in correct order in every language. Here is the code I use to fill the menu: bool:= IsDesktop(SelectedPIDL); if bool then OleCheck(SHGetDesktopFolder(CurFolder)) else OleCheck(DesktopShellFolder.BindToObject(SelectedPIDL, nil, IID_IShellFolder, Pointer(CurFolder))); if CurFolder.EnumObjects(0, SHCONTF_FOLDERS, EnumIDList) = NOERROR then begin while EnumIDList.Next(1, CurPidl, Fetched) = S_OK do begin FName:= GetDisplayName(CurFolder, CurPidl, SHGDN_NORMAL); Text:= GetPIDLNameForAddressBar(CurFolder, CurPidl); if bool then Text:= PSpecialFolderItem(SpecialFolders[0]).Name + '\' + Text; if Text[Length(Text)] <> '\' then Text:= Text + '\'; NewPidl:= ConcatPIDLs(SelectedPIDL, CurPidl); SHGetFileInfo(PChar(NewPidl), 0, SFI, SizeOf(SFI), SHGFI_ATTRIBUTES or SHGFI_PIDL or SHGFI_SYSICONINDEX or SHGFI_TYPENAME); n:= SFI.dwAttributes; MenuList.Add(GetAttr(n) + FName); AddMenuItem(Text, FName, SFI.iIcon); CoTaskMemFree(CurPidl); CoTaskMemFree(NewPidl); end; end; CoTaskMemFree(SelectedPIDL); Any solution for how to get the correct sorting order? It is strange there is no way in dwAttributes of TSHFileInfo to tell if a folder is a system folder. Roy M Klever

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• Problem: Sorting for GridView/ObjectDataSource changes depending on page

  - by user148298

  I have a GridView tied to an ObjectDataSource using paging. The paging works fine, except that the sort order changes depending on which page of the results is being viewed. This causes items to reappear on subsequent pages among other issues. I traced the problem to my DAL, which reads a page at a time and then sorts it. Obviously the sorting is going to change as the result set size changes. Is there an improvement to this algorithm. I would like to use a datareader if possible: [System.ComponentModel.DataObjectMethod(System.ComponentModel.DataObjectMethodType.Select)] public static WordsCollection LoadForCriteria(string sqlCriteria, int maximumRows, int startRowIndex, string sortExpression) { //DEFAULT SORT EXPRESSION if (string.IsNullOrEmpty(sortExpression)) sortExpression = "OrderBy"; //CREATE THE DYNAMIC SQL TO LOAD OBJECT StringBuilder selectQuery = new StringBuilder(); selectQuery.Append("SELECT"); if (maximumRows > 0) selectQuery.Append(" TOP " + (startRowIndex + maximumRows).ToString()); selectQuery.Append(" " + Words.GetColumnNames(string.Empty)); selectQuery.Append(" FROM sw_Words"); string whereClause = string.IsNullOrEmpty(sqlCriteria) ? string.Empty : " WHERE " + sqlCriteria; selectQuery.Append(whereClause); selectQuery.Append(" ORDER BY " + sortExpression); Database database = Token.Instance.Database; DbCommand selectCommand = database.GetSqlStringCommand(selectQuery.ToString()); //EXECUTE THE COMMAND WordsCollection results = new WordsCollection(); int thisIndex = 0; int rowCount = 0; using (IDataReader dr = database.ExecuteReader(selectCommand)) { while (dr.Read() && ((maximumRows < 1) || (rowCount < maximumRows))) { if (thisIndex >= startRowIndex) { Words varWords = new Words(); Words.LoadDataReader(varWords, dr); results.Add(varWords); rowCount++; } thisIndex++; } dr.Close(); } return results; }

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• Force maximum width and height for PHPThumb images

  - by Peter

  PHPThumb provides two great variables setting the output maximum width and height BUT "This is always overridden by ?w=_ GETstring parameter" $PHPTHUMB_CONFIG['output_maxwidth'] = 720; $PHPTHUMB_CONFIG['output_maxheight'] = 720; You can also set defaults, and for landscape/portrait: $PHPTHUMB_DEFAULTS['w'] = 720; $PHPTHUMB_DEFAULTS['h'] = 720; $PHPTHUMB_DEFAULTS['hp'] = 720; $PHPTHUMB_DEFAULTS['wl'] = 720; You can set the getsringoverride to enforce the default width/height but then you can't have width/height smaller than the default. $PHPTHUMB_DEFAULTS_GETSTRINGOVERRIDE = false; There doesn't seem to be a way to allow the get paramaters to be used but if entering a value higher than the output_maxwidth/height it outputs that size, not the maximum. How can the output be explicitly restricted to a maximum size, hence protecting the source images?

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• SVN Delete with wildcard?

  - by David Lively

  I'm migrating a VSS repository to SVN and inadvertently included all of the _vti_cnf, *.scc files in the first check-in. I'd like to remove these from SVN. (Not permanently, of course - just in the HEAD). The application in question is quite large, and finding and deleting these files on a folder-by-folder basis will take forever. Suggestions? There must be some obvious way to do this, but the proximity of the weekend is interfering with my higher brain functions.

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• PHP header redirection does nor reload <iframe> in IE

  - by Marco Demaio

  When displaying data from DB usually I'm in this situation I'm in page A.php that shows data from DB, user performs some action (like edit/delete etc) and page B.php is loaded to perform the action, once page B performed the action, it redirects browser to page A, page A is auto reloaded during step (3) therefor it shows an updated situation of the data In order to make page B to redirect to page A i use a simple PHP header("Location: " . "A.php", TRUE, 302); This works well in all situations, except when pages A.php is displaied into an <iframe>: in such a case it does not reload (step 4 does not get done). This seems to happen only in IE7 (don't know about IE8), it works perfectly on FF/Safari. And only when using an <iframe>, if page A.php is not in <iframe> it gest refreshed also in IE7. In order to solve this I simply added a couple of headers in page A.php to set it to not be cached: header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1 header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past But I was curious if you migt have exeperienced the same issue too in the past, and if you good give me some advises about this. Thanks!

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• linq get sum of two columns in one query

  - by Axarydax

  Hi, let's say that I have a table called Items (ID int, Done int, Total int) I can do it by two queries: int total = m.Items.Sum(p=>p.Total) int done = m.Items.Sum(p=>p.Done) But I'd like to do it in one query, something like this: var x = from p in m.Items select new { Sum(p.Total), Sum(p.Done)}; Surely there is a way to call aggregate functions from LINQ syntax...?

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• Transaction Isolation Level of Serializable not working for me

  - by Shahriar

  I have a website which is used by all branches of a store and what it does is that it records customer purchases into a table called myTransactions.myTransactions table has a column named SerialNumber.For each purchase i create a record in the transactions table and assign a serial to it.The stored procedure that does this calls a UDF function to get a new serialNumber before inserting the record.Like below : Create Procedure mytransaction_Insert as begin insert into myTransactions(column1,column2,column3,...SerialNumber) values( Value1 ,Value2,Value3,...., getTransactionNSerialNumber()) end Create function getTransactionNSerialNumber as begin RETURN isnull(SELECT TOP (1) SerialNumber FROM myTransactions READUNCOMMITTED ORDER BY SerialNumber DESC),0) + 1 end The website is being used by so many users in different stores at the same time and it is creating many duplicate serialNumbers(same SerialNumbers).So i added a Sql transaction with ReadCommitted level to the transaction and i still got duplicate transaction numbers.I changed it to SERIALIZABLE in order to lock the resources and i not only got duplicate transaction numbers(!!HOW!!) but i also got sporadic deadlocks between the same stored procedure calls.This is what i tried : (With ommissions of try catch blocks and rollbacks) Create Procedure mytransaction_Insert as begin SET TRANSACTION ISOLATION LEVEL SERIALIZABLE BEGIN TRASNACTION ins insert into myTransactions(column1,column2,column3,...SerialNumber) values( Value1 ,Value2 , Value3, ...., getTransactionNSerialNumber()) COMMIT TRANSACTION ins SET TRANSACTION ISOLATION READCOMMITTED end I even copied the function that gets the serial number directly into the stored procedure instead of the UDF function call and still got duplicate serialNumbers.So,How can a stored procedure line create something Like the c# lock() {} block. By the way,i have to implement the transaction serial number using the same pattern and i can't change the serialNumber to any other identity field or whatever.And for some reasons i need to generate the serialNumber inside the databse and i can't move SerialNumber generation to application level. Thank you.

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• How does a web browser work?

  - by Anil Namde

  I have tried to find good documentation of browsers using google but failed to get what I am looking for. Can someone guide me to a location where I can actually see how a browser functions? The whole purpose of the exercise is to get answers for following queries and more like these: How images, CSS and JS files are downloaded How JS is executed How an Ajax request is executed and many more like these..... Thanks all,

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• How to analyze the efficiency of this algorithm Part 2

  - by Leonardo Lopez

  I found an error in the way I explained this question before, so here it goes again: FUNCTION SEEK(A,X) 1. FOUND = FALSE 2. K = 1 3. WHILE (NOT FOUND) AND (K < N) a. IF (A[K] = X THEN 1. FOUND = TRUE b. ELSE 1. K = K + 1 4. RETURN Analyzing this algorithm (pseudocode), I can count the number of steps it takes to finish, and analyze its efficiency in theta notation, T(n), a linear algorithm. OK. This following code depends on the inner formulas inside the loop in order to finish, the deal is that there is no variable N in the code, therefore the efficiency of this algorithm will always be the same since we're assigning the value of 1 to both A & B variables: 1. A = 1 2. B = 1 3. UNTIL (B > 100) a. B = 2A - 2 b. A = A + 3 Now I believe this algorithm performs in constant time, always. But how can I use Algebra in order to find out how many steps it takes to finish?

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