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  • XAML Binding to complex value objects

    - by Gus
    I have a complex value object class that has 1) a number or read-only properties; 2) a private constructor; and 3) a number of static singleton instance properties [so the properties of a ComplexValueObject never change and an individual value is instantiated once in the application's lifecycle]. public class ComplexValueClass { /* A number of read only properties */ private readonly string _propertyOne; public string PropertyOne { get { return _propertyOne; } } private readonly string _propertyTwo; public string PropertyTwo { get { return _propertyTwo; } } /* a private constructor */ private ComplexValueClass(string propertyOne, string propertyTwo) { _propertyOne = propertyOne; _propertyTwo = PropertyTwo; } /* a number of singleton instances */ private static ComplexValueClass _complexValueObjectOne; public static ComplexValueClass ComplexValueObjectOne { get { if (_complexValueObjectOne == null) { _complexValueObjectOne = new ComplexValueClass("string one", "string two"); } return _complexValueObjectOne; } } private static ComplexValueClass _complexValueObjectTwo; public static ComplexValueClass ComplexValueObjectTwo { get { if (_complexValueObjectTwo == null) { _complexValueObjectTwo = new ComplexValueClass("string three", "string four"); } return _complexValueObjectTwo; } } } I have a data context class that looks something like this: public class DataContextClass : INotifyPropertyChanged { private ComplexValueClass _complexValueClass; public ComplexValueClass ComplexValueObject { get { return _complexValueClass; } set { _complexValueClass = value; PropertyChanged(this, new PropertyChangedEventArgs("ComplexValueObject")); } } } I would like to write a XAML binding statement to a property on my complex value object that updates the UI whenever the entire complex value object changes. What is the best and/or most concise way of doing this? I have something like: <Object Value="{Binding ComplexValueObject.PropertyOne}" /> but the UI does not update when ComplexValueObject as a whole changes.

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  • How to do inclusive range queries when only half-open range is supported (ala SortedMap.subMap)

    - by polygenelubricants
    On SortedMap.subMap This is the API for SortedMap<K,V>.subMap: SortedMap<K,V> subMap(K fromKey, K toKey) : Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive. This inclusive lower bound, exclusive upper bound combo ("half-open range") is something that is prevalent in Java, and while it does have its benefits, it also has its quirks, as we shall soon see. The following snippet illustrates a simple usage of subMap: static <K,V> SortedMap<K,V> someSortOfSortedMap() { return Collections.synchronizedSortedMap(new TreeMap<K,V>()); } //... SortedMap<Integer,String> map = someSortOfSortedMap(); map.put(1, "One"); map.put(3, "Three"); map.put(5, "Five"); map.put(7, "Seven"); map.put(9, "Nine"); System.out.println(map.subMap(0, 4)); // prints "{1=One, 3=Three}" System.out.println(map.subMap(3, 7)); // prints "{3=Three, 5=Five}" The last line is important: 7=Seven is excluded, due to the exclusive upper bound nature of subMap. Now suppose that we actually need an inclusive upper bound, then we could try to write a utility method like this: static <V> SortedMap<Integer,V> subMapInclusive(SortedMap<Integer,V> map, int from, int to) { return (to == Integer.MAX_VALUE) ? map.tailMap(from) : map.subMap(from, to + 1); } Then, continuing on with the above snippet, we get: System.out.println(subMapInclusive(map, 3, 7)); // prints "{3=Three, 5=Five, 7=Seven}" map.put(Integer.MAX_VALUE, "Infinity"); System.out.println(subMapInclusive(map, 5, Integer.MAX_VALUE)); // {5=Five, 7=Seven, 9=Nine, 2147483647=Infinity} A couple of key observations need to be made: The good news is that we don't care about the type of the values, but... subMapInclusive assumes Integer keys for to + 1 to work. A generic version that also takes e.g. Long keys is not possible (see related questions) Not to mention that for Long, we need to compare against Long.MAX_VALUE instead Overloads for the numeric primitive boxed types Byte, Character, etc, as keys, must all be written individually A special check need to be made for toInclusive == Integer.MAX_VALUE, because +1 would overflow, and subMap would throw IllegalArgumentException: fromKey > toKey This, generally speaking, is an overly ugly and overly specific solution What about String keys? Or some unknown type that may not even be Comparable<?>? So the question is: is it possible to write a general subMapInclusive method that takes a SortedMap<K,V>, and K fromKey, K toKey, and perform an inclusive-range subMap queries? Related questions Are upper bounds of indexed ranges always assumed to be exclusive? Is it possible to write a generic +1 method for numeric box types in Java? On NavigableMap It should be mentioned that there's a NavigableMap.subMap overload that takes two additional boolean variables to signify whether the bounds are inclusive or exclusive. Had this been made available in SortedMap, then none of the above would've even been asked. So working with a NavigableMap<K,V> for inclusive range queries would've been ideal, but while Collections provides utility methods for SortedMap (among other things), we aren't afforded the same luxury with NavigableMap. Related questions Writing a synchronized thread-safety wrapper for NavigableMap On API providing only exclusive upper bound range queries Does this highlight a problem with exclusive upper bound range queries? How were inclusive range queries done in the past when exclusive upper bound is the only available functionality?

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  • Questions and considerations to ask client for designing a database

    - by Julia
    Hi guys! so as title says, I would like to hear your advices what are the most important questions to consider and ask end-users before designing database for their application. We are to make database-oriented app, with special attenion to pay on db security (access control, encryption, integrity, backups)... Database will also keep some personal information about people, which is considered sensitive by law regulations, so security must be good. I worked on school projects with databases, but this is first time working "in real world", where this db security has real implications. So I found some advices and questions to ask on internet, but here I always get best ones. All help appreciated! Thank you!

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  • Algorithm on trajectory analysis.

    - by Arman
    Hello, I would like to analyse the trajectory data based on given templates. I need to stack the similar trajectories together. The data is a set of coordinates xy,xy,xy and the templates are again the lines defined by the set of control points. I don't know to what direction to go, maybe to Neural Networks or pattern recognition? Could you please advace me page, book or library to start with? kind regards Arman. PS. Is it the right place to ask the question?

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  • should this database table be normalized?

    - by oo
    i have taken over a database that stores fitness information and we were having a debate about a certain table and whether it should stay as one table or get broken up into three tables. Today, there is one table called: workouts that has the following fields id, exercise_id, reps, weight, date, person_id So if i did 2 sets of 3 different exercises on one day, i would have 6 records in that table for that day. for example: id, exercise_id, reps, weight, date, person_id 1, 1, 10, 100, 1/1/2010, 10 2, 1, 10, 100, 1/1/2010, 10 3, 1, 10, 100, 1/1/2010, 10 4, 2, 10, 100, 1/1/2010, 10 5, 2, 10, 100, 1/1/2010, 10 6, 2, 10, 100, 1/1/2010, 10 So the question is, given that there is some redundant data (date, personid, exercise_id) in multiple records, should this be normalized to three tables WorkoutSummary: - id - date - person_id WorkoutExercise: - id - workout_id (foreign key into WorkoutSummary) - exercise_id WorkoutSets: - id - workout_exercise_id (foreign key into WorkoutExercise) - reps - weight I would guess the downside is that the queries would be slower after this refactoring as now we would need to join 3 tables to do the same query that had no joins before. The benefit of the refactoring allows up in the future to add new fields at the workout summary level or the exercise level with out adding in more duplication. any feedback on this debate?

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  • Help converting some classic asp code to c# (.net 3.5)

    - by xoail
    I have this block of code in a .asp file that I am struggling to convert to c#... can anyone help me? Function EncodeCPT(ByVal sPinCode, ByVal iOfferCode, ByVal sShortKey, ByVal sLongKey) Dim vob(2), encodeModulo(256), decodeX, ocode decodeX = " abcdefghijklmnopqrstuvwxyz0123456789!$%()*+,-.@;<=>?[]^_{|}~" if len(iOfferCode) = 5 then ocode = iOfferCode Mod 10000 else ocode = iOfferCode end if vob(1) = ocode Mod 100 vob(0) = Int((ocode-vob(1)) / 100) For i = 1 To 256 encodeModulo(i) = 0 Next For i = 0 To 60 encodeModulo(asc(mid(decodeX, i + 1, 1))) = i Next 'append offer code to key sPinCode = lcase(sPinCode) & iOfferCode If Len(sPinCode) < 20 Then sPinCode = Left(sPinCode & " couponsincproduction", 20) End If 'encode Dim i, q, j, k, sCPT, s1, s2, s3 i = 0 q = 0 j = Len(sPinCode) k = Len(sShortKey) sCPT = "" For i = 1 To j s1 = encodeModulo(asc( mid(sPinCode, i, 1)) ) s2 = 2 * encodeModulo( asc( mid(sShortKey, 1 + ((i - 1) Mod k), 1) ) ) s3 = vob(i Mod 2) q = (q + s1 + s2 + s3) Mod 61 sCPT = sCPT & mid(sLongKey, q + 1, 1) Next EncodeCPT = sCPT End Function

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  • When is lazy evaluation not useful?

    - by Cherian
    Delay execution is almost always a boon. But then there are cases when it’s a problem and you resort to “fetch” (in Nhibernate) to eager fetch it. Do you know practical situations when lazy evaluation can bite you back…?

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  • Converting old WCF service to RIA one

    - by Artur
    Hi there, Currently I have a service that looks like: Some app <-- WCF Service <-- Business Logic <-- Entity Framework Model <-- SQL Database One of "some app" would be Silverlight, but there as well will be lots of other clients (mainly mobile devices). To me the greatest benefit of having RIA services is possibility of making ordinary (not asynchronous) calls from Silverlight. I wondered if there is an easy way of converting what I have so far to be a RIA service? I as well wonder if there is a point of doing so if I plan to use the same service for multiple platforms/clients? Any help/links would be greatly appreciated.

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  • Implementation of a general-purpose object structure (property bag)

    - by Thomas Wanner
    We need to implement some general-purpose object structure, much like an object in dynamic languages, that would give us a possibility of creating the whole object graph on-the-fly. This class has to be serializable and somehow user friendly. So far we have made some experiments with class derived from Dictionary<string, object> using the dot notation path to store properties and collections in the object tree. We have also find an article that implements something similar, but it doesn't seem to fit completely into our picture either. Do you know about some good implementations / libraries that deal with a similar problem or do you have any (non-trivial) ideas that could help us with our own implementation ? Also, I probably have to say that we are using .NET 3.5, so we can't take advantage of the new features in .NET 4.0 like dynamic type etc. (as far as I know it's also not possible to use any subset of it in .NET 3.5 solution).

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  • Pagination For SMS in Android specifically

    - by Priyank
    Hi. I had a pagination related question posted earlier. Here I went through the posted answers and suggested choices and I realized that to implement pagination in an application I could still write db level queries and ensure that I could implement pagination, even if in a crude form. However I have few follow up questions now: I am trying to show SMS from a content provider. Suppose I don't want to use content provider; can I access SMS table in database through my application. Aoes android's security framework allow that? How do people generally handle pagination problems in android, related to content that they are not storing but instead are fetching through content providers. (Android's own or custom) Isn't this a bigger problem. I am surprised to find so little text online about it.

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  • Need Database Help - A second opinion - thank you

    - by user287745
    i have designed an er model and then normalized it till the BCNF and converted it into tables using vs08. my problem is i do not know from where to get the normalized database checked to see if it has no mistakes in normalization- can not be further normalized. please do not give answers such as- ask a friend- ask your professor- do not have these resources available- it is very very hard and really time consuming waiting for the relevant person to be available. so are there any sites from where i can ask help from other designers- people like you to check the normalized database? please note:- it should be free, sorry for accept rate, was not aware of accepting the answers, all the help is appreciated thank you

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  • ColdFusion code parser?

    - by Kip
    I'm trying to create an app to search my company's ColdFusion codebase. I'd like to be able to do intelligent searches, for example: find where a function is defined (and not hit everywhere the function is called). In order to do this, I'd need to parse the ColdFusion code to identify things like function declarations, function calls, database queries, etc. I've looked into using lex and yacc, but I've never used them before and the learning curve seems very steep. I'm hoping there is something already out there that I could use. My other option is a mess of difficult-to-maintain regex-spaghetti code, which I want to avoid.

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  • mysql, sqlite database source code

    - by Yang
    hi guys, i know implementing database is a huge topic, but i want to have a basic understanding of how database systems works (e.g. memory management, binary tree, transaction, sql parsing, multi-threading, partitions, etc) by investigating the source code of the database, since there are a few already proven very robust open source databases like mysql, sqlite and so on. however, the code are very complicated and i have no clue where to start. also i find that the old school database textbooks are only explaining the theory, not the implementation details. Can anyone suggest how should i get started and is there any books that emphasis on the technology and techniques of building dbms used in modern database industry? Thank in advance!

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  • Why "alt" attribute for <img> tag has been considered mandatory by the HTML validator .. ?

    - by infant programmer
    Is there any logical or technical reason (with the W3C validation) for making alt as required attribute .. This is my actual problem:though my page is perfect enough with respect to W3C validation rules .. Only error I am getting is line XX column YY - Error: required attribute "ALT" not specified I know the significance of "alt" attribute and I have omitted that where it is unnecessary .. (to be more elaborate .. I have added the image to increase the beauty of my page and I don't want alt attribute to show irrelevant message to the viewer) getting rid of the error is secondary .. rather I am curious to know whether is it a flaw with validation rules .. ?? I thank stackOverflow and all the members who responded me .. I got my doubt clarified .. :-)

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  • Good tools which generate NUnit unit tests for .NET assemblies in Visual Studio 2008

    - by andy
    Hey guys, I'm pretty new to Unit Testing so bare with me. I realize that best best practice is not to auto generate unit tests, however I'd like to use Code Generation to set-up the basic skeleton of the tests. Now, I know Visual Studio 2008 already has the built in "create tests", however, it just creates a flat list of all the classes it's going to test... and it's not for NUnit right? Ideally, I'd like the code generation to follow the folder AND namespace structure of the assembly its generating tests for. Can you guys recommend any good tools which generate NUnit unit tests for .NET assemblies in Visual Studio 2008? cheers!

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  • Looking for efficient scaling patterns for Silverlight application with distributed text-file data s

    - by Edward Tanguay
    I'm designing a Silverlight software solution for students and teachers to record flashcards, e.g. words and phrases that students find while reading and errors that teachers notice while teaching. Requirements are: each person publishes his own flashcards in a file on a web server, e.g. http://:www.mywebserver.com/flashcards.txt other people subscribe to that person's flashcards by using a Silverlight flashcard reader that I have developed and entering the URLs of flashcard files they want to subscribe to, URLs and imported flashcards being saved in IsolatedStorage the flashcards.txt file has the following simple format: title, then blocks of question/answers: Jim Smith's flashcards from English class 53-222, winter semester 2009 ==fla Das kann nicht sein. That can't be. ==fla Es sei denn, er kommt nicht. Unless he doesn't come. The user then makes public the URL to his flashcard file and other readers begin reading in his flashcards. In order to lower the bar for non-technical users to contribute, it will even be possible for them to save this text in a Google Document, which they publish and distribute the URL. The flashcard readers will then recognize it is a google document and perform the necessary screen scraping to get at the raw text. I have two technical questions about this approach: What is a best way to plan now for scalability issues: e.g. if your reader is subscribed to 10 flashcard files that are each 200K, it will have to download 2MB of text just to find out if any new flashcards are available. Or can I somehow accurately and consistently get at the last update date/time of text files on servers and published google docs? Each reader will have the ability to allow the person to test himself on imported flashcards and add meta information to them, e.g. categorize them, edit them, etc. This information will be stored in IsolatedStorage along with the important flashcards themselves. What is a good pattern to allow these readers to share and synchronize this meta data, e.g. so when you are looking at a flashcard you can see that 5 other people have made corrections to it. The best solution I can think of now is that the Silverlight readers will have to republish their data to a central database, but then there is the problem of uniquely identifying each flashcard, the best approach seems to be URL + position-in-file, or even better URL + original text of both question and answer fields, but both of these have their obvious drawbacks. The main requirement is that the bar for participation is kept as low as possible, i.e. type text in a google document, publish it, distribute the URL, and you're publishing within the flashcard community. So I want to come up with the most efficient technical solutions in order to compensate for the lack of database, lack of unique ids, etc. For those who have designed or developed similar non-traditional, distributed database projects like this, what advice, experience or best-practice tips you can share on the above two points?

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  • Single value data to multiple values of data in database relation

    - by Sofiane Merah
    I have such a hard time picturing this. I just don't have the brain to do it. I have a table called reports. --------------------------------------------- | report_id | set_of_bads | field1 | field2 | --------------------------------------------- | 123 | set1 | qwe | qwe | --------------------------------------------- | 321 | 123112 | ewq | ewq | --------------------------------------------- I have another table called bads. This table contains a list of bad data. ------------------------------------- | bad_id | set_it_belongs_to | field2 | field3 | ------------------------------------- | 1 | set1 | qwe | qwe | ------------------------------------- | 2 | set1 | qee | tte | ------------------------------------- | 3 | set1 | q44w | 3qwe | ------------------------------------- | 4 | 234 | qoow | 3qwe | ------------------------------------- Now I have set the first field of every table as the primary key. My question is, how do I connect the field set_of_bads to set_it_belongs_to in the bads table. This way if I want to get the entire set of data that is set1 by calling on the reports table I can do it. Example: hey reports table.. bring up the row that has the report_id 123. Okay thank you.. Now get all the rows from bads that has the set_of_bads value from the row with the report_id 123. Thanks.

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  • How to avoid using this in a contructor

    - by Paralife
    I have this situation: interface MessageListener { void onMessageReceipt(Message message); } class MessageReceiver { MessageListener listener; public MessageReceiver(MessageListener listener, other arguments...) { this.listener = listener; } loop() { Message message = nextMessage(); listener.onMessageReceipt(message); } } and I want to avoid the following pattern: (Using the this in the Client constructor) class Client implements MessageListener { MessageReceiver receiver; MessageSender sender; public Client(...) { receiver = new MessageReceiver(this, other arguments...); sender = new Sender(...); } . . . @Override public void onMessageReceipt(Message message) { if(Message.isGood()) sender.send("Congrtulations"); else sender.send("Boooooooo"); } } The reason why i need the above functionality is because i want to call the sender inside the onMessageReceipt() function, for example to send a reply. But I dont want to pass the sender into a listener, so the only way I can think of is containing the sender in a class that implements the listener, hence the above resulting Client implementation. Is there a way to achive this without the use of 'this' in the constructor? It feels bizare and i dont like it, since i am passing myself to an object(MessageReceiver) before I am fully constructed. On the other hand, the MessageReceiver is not passed from outside, it is constructed inside, but does this 'purifies' the bizarre pattern? I am seeking for an alternative or an assurance of some kind that this is safe, or situations on which it might backfire on me.

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  • Relational vs. Dimensional Databases, what's the difference?

    - by grautur
    I'm trying to learn about OLAP and data warehousing, and I'm confused about the difference between relational and dimensional modeling. Is dimensional modeling basically relational modeling, but allowing for redundant/un-normalized data? For example, let's say I have historical sales data on (product, city, # sales). I understand that the following would be a relational point-of-view: Product | City | # Sales Apples, San Francisco, 400 Apples, Boston, 700 Apples, Seattle, 600 Oranges, San Francisco, 550 Oranges, Boston, 500 Oranges, Seattle, 600 While the following is a more dimensional point-of-view: Product | San Francisco | Boston | Seattle Apples, 400, 700, 600 Oranges, 550, 500, 600 But it seems like both points of view would nonetheless be implemented in an identical star schema: Fact table: Product ID, Region ID, # Sales Product dimension: Product ID, Product Name City dimension: City ID, City Name And it's not until you start adding some additional details to each dimension that the differences start popping up. For instance, if you wanted to track regions as well, a relational database would tend to have a separate region table, in order to keep everything normalized: City dimension: City ID, City Name, Region ID Region dimension: Region ID, Region Name, Region Manager, # Regional Stores While a dimensional database would allow for denormalization to keep the region data inside the city dimension, in order to make it easier to slice the data: City dimension: City ID, City Name, Region Name, Region Manager, # Regional Stores Is this correct?

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  • Confused about this factory, as it doesn't look like an Abstract Factory nor Factory Method

    - by Pin
    I'm looking into Guice and I've been reading its documentation recently. Reading the motivation section I don't understand the factories part, why they name it that way. To me that factory is just a wrapper for the implementing class they want it to return after calling getInstance(). public class CreditCardProcessorFactory { private static CreditCardProcessor instance; public static void setInstance(CreditCardProcessor creditCardProcessor) { instance = creditCardProcessor; } public static CreditCardProcessor getInstance() { if (instance == null) { throw new IllegalStateException("CreditCardProcessorFactory not initialized. " + "Did you forget to call CreditCardProcessor.setInstance() ?"); } return instance; } } Why do they call it factory as well if it is neither an abstract factory nor a factory method? Or am I missing something? Thanks.

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  • Web user expectations

    - by Ash
    When designing a good Web GUI what expectations can we expect from an end user? I've come up with the following, but I wonder if there are any others which can suggest.. If I click on a hyperlink it will take me to another page/part of this page If I tick/untick a checkbox it might alter the page state (enable/disable elements) If I click on a button I expect it to do something to data. If I click on a button I expect something to happen immediately (either to the current page, or for me to be taken to another page) If I have clicked on a hyperlink and it has taken me to another page, I expect to be able to use the Back button to get back to the previous page in a state similar to that which I left it in If I change something in a form, I can change it back to its previous value if necessary Unless I click on the 'Submit' button nothing should happen to my data. If I bookmark/favourite a page then it should show the same related data each time I visit it If text is underlined and looks like a link, it should be a link and act as one The reasoning behind this question is more a 'UI from hell' one. For example I have come across pages which checking a tickbox next to a record will delete it, straight away, via ajax. To me that just seems wrong, a checkbox is a toggle - something which a delete operation definitely isn't!

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  • Algorithm to match list of regular expressions

    - by DSII
    I have two algorithmic questions for a project I am working on. I have thought about these, and have some suspicions, but I would love to hear the community's input as well. Suppose I have a string, and a list of N regular expressions (actually they are wildcard patterns representing a subset of full regex functionality). I want to know whether the string matches at least one of the regular expressions in the list. Is there a data structure that can allow me to match the string against the list of regular expressions in sublinear (presumably logarithmic) time? This is an extension of the previous problem. Suppose I have the same situation: a string and a list of N regular expressions, only now each of the regular expressions is paired with an offset within the string at which the match must begin (or, if you prefer, each of the regular expressions must match a substring of the given string beginning at the given offset). To give an example, suppose I had the string: This is a test string and the regex patterns and offsets: (a) his.* at offset 0 (b) his.* at offset 1 The algorithm should return true. Although regex (a) does not match the string beginning at offset 0, regex (b) does match the substring beginning at offset 1 ("his is a test string"). Is there a data structure that can allow me to solve this problem in sublinear time? One possibly useful piece of information is that often, many of the offsets in the list of regular expressions are the same (i.e. often we are matching the substring at offset X many times). This may be useful to leverage the solution to problem #1 above. Thank you very much in advance for any suggestions you may have!

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  • Storing varchar(max) & varbinary(max) together - Problem?

    - by Tony Basallo
    I have an app that will have entries of both varchar(max) and varbinary(max) data types. I was considering putting these both in a separate table, together, even if only one of the two will be used at any given time. The question is whether storing them together has any impact on performance. Considering that they are stored in the heap, I'm thinking that having them together will not be a problem. However, the varchar(max) column will be probably have the text in row table option set. I couldn't find any performance testing or profiling while "googling bing," probably too specific a question? The SQL Server 2008 table looks like this: Id ParentId Version VersionDate StringContent - varchar(max) BinaryContent - varbinary(max) The app will decide which of the two columns to select for when the data is queried. The string column will much used much more frequently than the binary column - will this have any impact on performance?

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