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  • Refining data stored in SQLite - how to join several contacts?

    - by Krab
    Problem background Imagine this problem. You have a water molecule which is in contact with other molecules (if the contact is a hydrogen bond, there can be 4 other molecules around my water). Like in the following picture (A, B, C, D are some other atoms and dots mean the contact). A B . . O / \ H H . . C D I have the information about all the dots and I need to eliminate the water in the center and create records describing contacts of A-C, A-D, A-B, B-C, B-D, and C-D. Database structure Currently, I have the following structure in the database: Table atoms: "id" integer PRIMARY KEY, "amino" char(3) NOT NULL, (HOH for water or other value) other columns identifying the atom Table contacts: "acceptor_id" integer NOT NULL, (the atom near to my hydrogen, here C or D) "donor_id" integer NOT NULL, (here A or B) "directness" char(1) NOT NULL, (this should be D for direct and W for water-mediated) other columns about the contact, such as the distance Current solution (insufficient) Now, I'm going through all the contacts which have donor.amino = "HOH". In this sample case, this would select contacts from C and D. For each of these selected contacts, I look up contacts having the same acceptor_id as is the donor_id in the currently selected contact. From this information, I create the new contact. At the end, I delete all contacts to or from HOH. This way, I am obviously unable to create C-D and A-B contacts (the other 4 are OK). If I try a similar approach - trying to find two contacts having the same donor_id, I end up with duplicate contacts (C-D and D-C). Is there a simple way to retrieve all six contacts without duplicates? I'm dreaming about some one page long SQL query which retrievs just these six wanted rows. :-) It is preferable to conserve information about who is donor where possible, but not strictly necessary. Big thanks to all of you who read this question to this point.

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  • LinqKit stack overflow exception using predicate builder

    - by MLynn
    I am writing an application in C# using LINQ and LINQKit. I have a very large database table with company registration numbers in it. I want to do a LINQ query which will produce the equivalent SQL: select * from table1 where regno in('123','456') The 'in' clause may have thousands of terms. First I get the company registration numbers from a field such as Country. I then add all the company registration numbers to a predicate: var predicate = PredicateExtensions.False<table2>(); if (RegNos != null) { foreach (int searchTerm in RegNos) { int temp = searchTerm; predicate = predicate.Or(ec => ec.regno.Equals(temp)); } } On Windows Vista Professional a stack overflow exception occured after 4063 terms were added. On Windows Server 2003 a stack overflow exception occured after about 1000 terms were added. I had to solve this problem quickly for a demo. To solve the problem I used this notation: var predicate = PredicateExtensions.False<table2>(); if (RegNosDistinct != null) { predicate = predicate.Or(ec => RegNos.Contains(ec.regno)); } My questions are: Why does a stack overflow occur using the foreach loop? I take it Windows Server 2003 has a much smaller stack per process\thread than NT\2000\XP\Vista\Windows 7 workstation versions of Windows. Which is the fastest and most correct way to achieve this using LINQ and LINQKit? It was suggested I stop using LINQ and go back to dynamic SQL or ADO.NET but I think using LINQ and LINQKit is far better for maintainability.

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  • Design pattern to keep track UITableView rows correspondance to underlying data in constant time.

    - by DenNukem
    When my model changes I want to animate changes in UITableView by inserting/deleting rows. For that I need to know the ordinal of the given row (so I can construct NSIndexPath), which I find hard to do in better-than-linear time. For example, consider that I have a list of addressbook entries which are manualy sorted by the user, i.e. there is no ordering "key" that represents the sort order. There is also a corresponding UITableView that shows one row per addressbook entry. When UITableView queries the datasource I query the NSMUtableArray populated with my entries and return required data in constant time for each row. However, if there is a change in underlying model I am getting a notification "Joe Smith, id#123 has been removed". Now I have a dilemma. A naive approach would be to scan the array, determine the index at which Joe Smith is and then ask UITableView to remove that precise row from the view, also removing it form the array. However, the scan will take linear time to finish. Now I could have an NSDictionary which allows me to find Joe Smith in constant time, but that doesn't do me a lot of good because I still need to find his ordinal index within the array in order to instruct UITableView to remove that row, which is again a linear search. I could further decide to store each object's ordinal inside the object itself to make it constant, but it will become outdated after first such update as all subsequent index values will have changed due to removal of an object. So what is the correct design pattern to accurately reflect model changes in the UITableView in costant (or at least logarithmic) time?

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  • Getting identity from Ado.Net Update command

    - by rboarman
    My scenario is simple. I am trying to persist a DataSet and have the identity column filled in so I can add child records. Here's what I've got so far: using (SqlConnection connection = new SqlConnection(connStr)) { SqlDataAdapter adapter = new SqlDataAdapter("select * from assets where 0 = 1", connection); adapter.MissingMappingAction = MissingMappingAction.Passthrough; adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey; SqlCommandBuilder cb = new SqlCommandBuilder(adapter); var insertCmd = cb.GetInsertCommand(true); insertCmd.Connection = connection; connection.Open(); adapter.InsertCommand = insertCmd; adapter.InsertCommand.CommandText += "; set ? = SCOPE_IDENTITY()"; adapter.InsertCommand.UpdatedRowSource = UpdateRowSource.OutputParameters; var param = new SqlParameter("RowId", SqlDbType.Int); param.SourceColumn = "RowId"; param.Direction = ParameterDirection.Output; adapter.InsertCommand.Parameters.Add(param); SqlTransaction transaction = connection.BeginTransaction(); insertCmd.Transaction = transaction; try { assetsImported = adapter.Update(dataSet.Tables["Assets"]); transaction.Commit(); } catch (Exception ex) { transaction.Rollback(); // Log an error } connection.Close(); } The first thing that I noticed, besides the fact that the identity value is not making its way back into the DataSet, is that my change to add the scope_identity select statement to the insert command is not being executed. Looking at the query using Profiler, I do not see my addition to the insert command. Questions: 1) Why is my addition to the insert command not making its way to the sql being executed on the database? 2) Is there a simpler way to have my DataSet refreshed with the identity values of the inserted rows? 3) Should I use the OnRowUpdated callback to add my child records? My plan was to loop through the rows after the Update() call and add children as needed. Thank you in advance. Rick

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  • Select box is not working properly after including google custom search box in web page

    - by Vinay
    I have got a select box and google custom search box in a page, when i choose a option from select box and navigate away from the page and again if i come back to the same page the option will not be selected (violates the default functionality of select box), The code is below <script src="https://www.google.com/jsapi" type="text/javascript"></script> <script type="text/javascript"> google.load('search', '1', {language : 'en'}); google.setOnLoadCallback(function() { var customSearchControl = new google.search.CustomSearchControl('004920913350056953771:kpkclvhujzk'); customSearchControl.setResultSetSize(google.search.Search.FILTERED_CSE_RESULTSET); var options = new google.search.DrawOptions(); options.setAutoComplete(true); options.enableSearchboxOnly("<?=$homeurl?>my_results.php", "query"); customSearchControl.draw('cse-search-form', options); }, true); </script> <select multiple="yes"> <option>1</option> <option>2</option> </select> If i remove the custom search script, the select box selected option will be retained even after navigating away from the page. (default functionality) Its working fine in chrome, IE but not in Firefox. Is there any solution for this, so that select box must work fine even in the presence of search box, but the order must be same 1) Search box 2)Select Box

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  • Creating dynamic jQuery tooltips for dynamic content

    - by Mel
    I'm using the qTip jQuery plugin to create tooltips for a set of links. Two problems: How do I create a set of tooltips for three dynamically generated links where the content of the tooltip will also be dynamic: a href="books.cfm?bookID=11"Book One a href="books.cfm?bookID=22"Book Two a href="books.cfm?bookID=33"Book Three I would like to create a tooltip for each link. Each tooltip will then load details about each book. Thus I must pass the bookID to the tooltip: $('#catalog a[href]').each(function() { $(this).qtip( { content: { URL: 'cfcs/viewbooks.cfc?method=bookDetails', data: { bookID: <cfoutput>#indexView.bookID#</cfoutput> }, method: 'get' } }); }); Unfortunately the above code is not working correctly. I've gotten it to work when I've used a static 'bookID' instead of a dynamically generated number. Even when it does work (by using a static number for 'bookID', I can't format the data correctly. It comes back as a query result, or a bunch of text strings. Should I send back the results as HTML? Unsure. PS: I am an absolute NOVICE to Javascript and jQuery, so please try not to be as technical. Many thanks!

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  • Grails UrlMappings with .html

    - by Glennn
    I'm developing a Grails web application (mainly as a learning exercise). I have previously written some standard Grails apps, but in this case I wanted to try creating a controller that would intercept all requests (including static html) of the form: <a href="/testApp/testJsp.jsp">test 1</a> <a href="/testApp/testGsp.gsp">test 2</a> <a href="/testApp/testHtm.htm">test 3</a> <a href="/testApp/testHtml.html">test 4</a> The intent is to do some simple business logic (auditing) each time a user clicks a link. I know I could do this using a Filter (or a range of other methods), however I thought this should work too and wanted to do this using a Grails framework. I set up the Grail UrlMappings.groovy file to map all URLs of that form (/$myPathParam?) to a single controller: class UrlMappings { static mappings = { "/$controller/$action?/$id?"{ constraints { } } "/$path?" (controller: 'auditRecord', action: 'showPage') "500"(view:'/error') } } In that controller (in the appropriate "showPage" action) I've been printing out the path information, for example: def showPage = { println "params.path = " + params.path ... render(view: resultingView) } The results of the println in the showPage action for each of my four links are testJsp.jsp testGsp.gsp testHtm.htm testHtml Why is the last one "testHtml", not "testHtml.html"? In a previous (Stack Overflow query) Olexandr encountered this issue and was advised to simply concatenate the value of request.format - which, indeed, does return "html". However request.format also returns "html" for all four links. I'm interested in gaining an understanding of what Grails is doing and why. Is there some way to configure Grails so the params.path variable in the controller shows "testHtml.html" rather than stripping off the "html" extension? It doesn't seem to remove the extension for any other file type (including .htm). Is there a good reason it's doing this? I know that it is a bit unusual to use a controller for static html, but still would like to understand what's going on.

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  • Something preventing default (explorer-style) CListCtrl jump to line behaviour

    - by andywebsdale
    I'm maintaining an MFC/COM/ATL 45-odd project solution originally written with VS6. I'm now using VS2008. I'm looking at a list control(vanilla CListCtrl) which doesn't behave as we think it should. Normally in an MFC list control you can press a key, (Q say) & selection will jump down to the 1st line beginning with 'Q' (like windows explorer). Does anyone have an idea as to why this might not happen? The styles/Extended styles are set the same as another control in the same project, which DOES work OK. Do I have to send my own message, or is there a flag, etc. that controls that functionality or what? Normally Google would supply the answer, but I haven't been able to frame my query correctly to come up with the relevant info this time. Here's the line from the .rc file for the CListCtrl that doesn't jump to a line on keypress: CONTROL "List1",IDC_BAL_LIST,"SysListView32",LVS_REPORT | LVS_SHOWSELALWAYS | WS_BORDER | WS_TABSTOP,0,73,493,230 And here's a line from the same .rc file showing a list control that does do that: CONTROL "List1",IDC_LIST1,"SysListView32",LVS_REPORT | LVS_SHOWSELALWAYS | WS_BORDER | WS_TABSTOP,1,38,501,219 As you can see, there's no obvious difference to the properties, so what program code would affect it?

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  • DataReader-DataSet Hybrid solution

    - by G33kKahuna
    My solution architects and I have exhausted both pure Dataset and Datareader solutions. Basically we have a Microsoft.NET 2.0 windows service application that pulls data based on a query and processes additional tasks per record; almost a poor mans workflow system. The recordsets are broader (in terms of the columns) and deeper (in terms of number of records). We observed that DataSet performs much better in terms of performance but runs into contraints as # of records increase say 100K+ we start seeing System.OutOfMemoryException on a 4G machine with processModel configured to run at memoryLimit set to 85. Since this is a multi-threaded app, there could be multiple threads processing different queries and building different DataSets, so we run into the exception sooner in that case DataReader on the other hand works but is a lot slower and hits other contraints; if there is some sort of disconnect it has to start over again or leaves open connections on the DB side and worst case takes down the service completely etc. So, we decided the best option would be some sort of hybrid solution. I'm open to guidance and suggestions. Are there any hybrid solutions available? Any other suggestions

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  • Row Source - combo box, filtering what pops up in a combo box by date

    - by primus285
    so I have a combo box that I want to pop up when somebody wants to search by year. It will allow them to see in that combo box only results that happened in a certain year. so far I have something like SELECT DISTINCT Database_New.ASEC FROM Database_New WHERE (((Database_New.Date) >= DateValue('01/01/2001') AND (((Database_New.Date) <= DateValue('12/031/2001'))); or SELECT DISTINCT Database_New.ASEC FROM Database_New WHERE (((Database_New.Date) >= BETWEEN DateValue('01/01/2001') AND DateValue('12/31/2001’))); as you can see, the kicker is that I am already sorting the thing with SELECT DISTINCT under the ASEC field. But I want to filter it one more by year so a whole bunch of ASEC values that didnt happen in that year (and there are quite a few that happen rarely, or would onyl be associeted with one year) do not pop up as avalible. so far I get an error like "Syntax error in query expression '(((Database_New.Date) = DateValue('01/01/2001') AND (((Database_New.Date) <= DateValue('12/031/2001')))' and I am a VBA person, not quite as good at debuggin SQL. Is it something easy? or will it simply not work the way I have it set up.

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  • How can I solve this NHibernate Querying in an n-tier architecture?

    - by Tyler Wright
    I've hit a wall with trying to decouple NHibernate from my services layer. My architecture looks like this: web - services - repositories - nhibernate - db I want to be able to spawn nhibernate queries from my services layer and possibly my web layer without those layers knowing what orm they are dealing with. Currently, I have a find method on all of my repositories that takes in IList<object[]> criteria. This allows me to pass in a list of criteria such as new object() {"Username", usernameVariable}; from anywhere in my architecture. NHibernate takes this in and creates a new Criteria object and adds in the passed in criteria. This works fine for basic searches from my service layer, but I would like to have the ability to pass in a query object that my repository translates into an NHibernate Criteria. Really, I would love to implement something like what is described in this question: Is there value in abstracting nhibernate criterion. I'm just not finding any good resources on how to implement something like this. Is the method described in that question a good approach? If so, could anyone provide some pointers on how to implement such a solution?

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  • java inserting special characters with preparedstatement fails

    - by phill
    I am using an HTML form which sends <input type=hidden name=longdesc value='SMARTNET%^" 8X5XNBD'> this is done by the following javascript code: function masinsert(id) { var currentTime=new Date(); var button = document.getElementById("m"+id); button.onclick=""; button.value="Inserting"; var itemdescription = document.getElementById("itemdescription"+id).value; function handleHttpResponse() { if (http.readyState == 4) { button.value="Item Added"; } } var http = getHTTPObject(); // We create the HTTP Object var tempUrl = "\AInsert"; tempUrl += "itemdescription="+itemdescription+"&"+"itemshortdescription="+itemdescription.substring(0,37)+; alert(tempUrl); http.open("GET", tempUrl, true); http.onreadystatechange = handleHttpResponse; http.send(null); } to a java servlet. AInsert.java in the AInsert.java file, I do a String itemdescription = request.getParameter("longdesc"); which then sends the value to a preparedstatement to run an insert query. In the query, there are sometimes special characters which throw it off. For example, when I run the following insert into itemdescription (longdesc) values ('SMARTNET%^" 8X5XNBD') here is the actual snippet: PreparedStatement ps = conn.prepareStatement("INSERT INTO itemdescription (longdesc) values(?)"); ps.setString(1, itemdescription); ps.executeUpdate(); It will produce an error saying : Cannot insert the value NULL into column 'LongDesc', table 'App.dbo.itemdescription'; column does not allow nulls. Insert fails I have tried urlencode/urldecode String encodedString = URLEncoder.encode(longdesc, "UTF-8"); String decitemdescription = URLDecoder.decode(itemdescription, "UTF-8"); and i've also tried these functions //BEGIN URL Encoder final static String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05", "%06", "%07", "%08", "%09", "%0a", "%0b", "%0c", "%0d", "%0e", "%0f", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17", "%18", "%19", "%1a", "%1b", "%1c", "%1d", "%1e", "%1f", "%20", "%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29", "%2a", "%2b", "%2c", "%2d", "%2e", "%2f", "%30", "%31", "%32", "%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3a", "%3b", "%3c", "%3d", "%3e", "%3f", "%40", "%41", "%42", "%43", "%44", "%45", "%46", "%47", "%48", "%49", "%4a", "%4b", "%4c", "%4d", "%4e", "%4f", "%50", "%51", "%52", "%53", "%54", "%55", "%56", "%57", "%58", "%59", "%5a", "%5b", "%5c", "%5d", "%5e", "%5f", "%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67", "%68", "%69", "%6a", "%6b", "%6c", "%6d", "%6e", "%6f", "%70", "%71", "%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79", "%7a", "%7b", "%7c", "%7d", "%7e", "%7f", "%80", "%81", "%82", "%83", "%84", "%85", "%86", "%87", "%88", "%89", "%8a", "%8b", "%8c", "%8d", "%8e", "%8f", "%90", "%91", "%92", "%93", "%94", "%95", "%96", "%97", "%98", "%99", "%9a", "%9b", "%9c", "%9d", "%9e", "%9f", "%a0", "%a1", "%a2", "%a3", "%a4", "%a5", "%a6", "%a7", "%a8", "%a9", "%aa", "%ab", "%ac", "%ad", "%ae", "%af", "%b0", "%b1", "%b2", "%b3", "%b4", "%b5", "%b6", "%b7", "%b8", "%b9", "%ba", "%bb", "%bc", "%bd", "%be", "%bf", "%c0", "%c1", "%c2", "%c3", "%c4", "%c5", "%c6", "%c7", "%c8", "%c9", "%ca", "%cb", "%cc", "%cd", "%ce", "%cf", "%d0", "%d1", "%d2", "%d3", "%d4", "%d5", "%d6", "%d7", "%d8", "%d9", "%da", "%db", "%dc", "%dd", "%de", "%df", "%e0", "%e1", "%e2", "%e3", "%e4", "%e5", "%e6", "%e7", "%e8", "%e9", "%ea", "%eb", "%ec", "%ed", "%ee", "%ef", "%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7", "%f8", "%f9", "%fa", "%fb", "%fc", "%fd", "%fe", "%ff" }; /** * Encode a string to the "x-www-form-urlencoded" form, enhanced * with the UTF-8-in-URL proposal. This is what happens: * * <ul> * <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z', * and '0' through '9' remain the same. * * <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the same. * * <li><p>The space character ' ' is converted into a plus sign '+'. * * <li><p>All other ASCII characters are converted into the * 3-character string "%xy", where xy is * the two-digit hexadecimal representation of the character * code * * <li><p>All non-ASCII characters are encoded in two steps: first * to a sequence of 2 or 3 bytes, using the UTF-8 algorithm; * secondly each of these bytes is encoded as "%xx". * </ul> * * @param s The string to be encoded * @return The encoded string */ public static String encode(String s) { StringBuffer sbuf = new StringBuffer(); int len = s.length(); for (int i = 0; i < len; i++) { int ch = s.charAt(i); if ('A' <= ch && ch <= 'Z') { // 'A'..'Z' sbuf.append((char)ch); } else if ('a' <= ch && ch <= 'z') { // 'a'..'z' sbuf.append((char)ch); } else if ('0' <= ch && ch <= '9') { // '0'..'9' sbuf.append((char)ch); } else if (ch == ' ') { // space sbuf.append('+'); } else if (ch == '-' || ch == '_' // unreserved || ch == '.' || ch == '!' || ch == '~' || ch == '*' || ch == '\'' || ch == '(' || ch == ')') { sbuf.append((char)ch); } else if (ch <= 0x007f) { // other ASCII sbuf.append(hex[ch]); } else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF sbuf.append(hex[0xc0 | (ch >> 6)]); sbuf.append(hex[0x80 | (ch & 0x3F)]); } else { // 0x7FF < ch <= 0xFFFF sbuf.append(hex[0xe0 | (ch >> 12)]); sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]); sbuf.append(hex[0x80 | (ch & 0x3F)]); } } return sbuf.toString(); } //end encode and //decode url private static String unescape(String s) { StringBuffer sbuf = new StringBuffer () ; int l = s.length() ; int ch = -1 ; int b, sumb = 0; for (int i = 0, more = -1 ; i < l ; i++) { /* Get next byte b from URL segment s */ switch (ch = s.charAt(i)) { case '%': ch = s.charAt (++i) ; int hb = (Character.isDigit ((char) ch) ? ch - '0' : 10+Character.toLowerCase((char) ch) - 'a') & 0xF ; ch = s.charAt (++i) ; int lb = (Character.isDigit ((char) ch) ? ch - '0' : 10+Character.toLowerCase ((char) ch)-'a') & 0xF ; b = (hb << 4) | lb ; break ; case '+': b = ' ' ; break ; default: b = ch ; } /* Decode byte b as UTF-8, sumb collects incomplete chars */ if ((b & 0xc0) == 0x80) { // 10xxxxxx (continuation byte) sumb = (sumb << 6) | (b & 0x3f) ; // Add 6 bits to sumb if (--more == 0) sbuf.append((char) sumb) ; // Add char to sbuf } else if ((b & 0x80) == 0x00) { // 0xxxxxxx (yields 7 bits) sbuf.append((char) b) ; // Store in sbuf } else if ((b & 0xe0) == 0xc0) { // 110xxxxx (yields 5 bits) sumb = b & 0x1f; more = 1; // Expect 1 more byte } else if ((b & 0xf0) == 0xe0) { // 1110xxxx (yields 4 bits) sumb = b & 0x0f; more = 2; // Expect 2 more bytes } else if ((b & 0xf8) == 0xf0) { // 11110xxx (yields 3 bits) sumb = b & 0x07; more = 3; // Expect 3 more bytes } else if ((b & 0xfc) == 0xf8) { // 111110xx (yields 2 bits) sumb = b & 0x03; more = 4; // Expect 4 more bytes } else /*if ((b & 0xfe) == 0xfc)*/ { // 1111110x (yields 1 bit) sumb = b & 0x01; more = 5; // Expect 5 more bytes } /* We don't test if the UTF-8 encoding is well-formed */ } return sbuf.toString() ; } but the decoding doesn't change it back to the original special characters. Any ideas? thanks in advance UPDATE: I tried adding these two statements to grab the request String itemdescription = URLDecoder.decode(request.getParameter("itemdescription"), "UTF-8"); String itemshortdescription = URLDecoder.decode(request.getParameter("itemshortdescription"), "UTF-8"); System.out.println("processRequest | short descrip "); and this is failing as well if that helps. UPDATE2: I created an html form and did a direct insert with the encoded itemdescription such as and the insertion works correctly with the special charaters and everything. I guess there is something going on with my javascript submit. Any ideas on this?

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  • Partial Evaluation of ConstantExpression in ExpressionTreeVisitor

    - by Andrew Theken
    Hi all, I am not an Expression Tree master by any stretch of the imagination, what I have is code that looks like this: int external = 10; using(var session = new Session()) { session.Add(new Product { Name = "test1", Price = 20 }); session.Add(new Product {Name = "test", Price = 10}); var product = session.Products.Where(p => p.Price == external).FirstOrDefault(); Assert.Equal(10, product.Price); } Session implements all the IQueryProvider, IQueryable interfaces you'd come to expect from a LINQ Provider. When I execute the query, everything goes to plan until I read the ConstantExpression for "external", at which point, I am at a loss as to how to move forward because: //constant is ConstantExpression for "external" on the right side of the "p.Price == external" expression above. var t = constant.GetType(); //evaluates to class called "<>c__DisplayClass2" - with a member named "external" that has the value 10. The question is basically.. How can I just access the value of the member "external" - is there a way to accomplish this without using reflection? or am I cooked? What am I missing?

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  • What is the best database structure for this scenario?

    - by Ricketts
    I have a database that is holding real estate MLS (Multiple Listing Service) data. Currently, I have a single table that holds all the listing attributes (price, address, sqft, etc.). There are several different property types (residential, commercial, rental, income, land, etc.) and each property type share a majority of the attributes, but there are a few that are unique to that property type. My question is the shared attributes are in excess of 250 fields and this seems like too many fields to have in a single table. My thought is I could break them out into an EAV (Entity-Attribute-Value) format, but I've read many bad things about that and it would make running queries a real pain as any of the 250 fields could be searched on. If I were to go that route, I'd literally have to pull all the data out of the EAV table, grouped by listing id, merge it on the application side, then run my query against the in memory object collection. This also does not seem very efficient. I am looking for some ideas or recommendations on which way to proceed. Perhaps the 250+ field table is the only way to proceed. Just as a note, I'm using SQL Server 2012, .NET 4.5 w/ Entity Framework 5, C# and data is passed to asp.net web application via WCF service. Thanks in advance.

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  • How should I manage my many-to-many relationships?

    - by wes
    Hello all, I have a database containing a couple tables: files and users. This relationship is many-to-many, so I also have a table called users_files_ref which holds foreign keys to both of the above tables. Here's the schema of each table: files - file_id, file_name users - user_id, user_name users_files_ref - user_file_ref_id, user_id, file_id I'm using Codeigniter to build a file host application, and I'm right in the middle of adding the functionality that enables users to upload files. This is where I'm running into my problem. Once I add a file to the files table, I will need that new file's id to update the users_files_ref table. Right now I'm adding the record to the files table, and then I imagined I'd run a query to grab the last file added, so that I can get the ID, and then use that ID to insert the new users_files_ref record. I know this will work on a small scale, but I imagine there is a better way of managing these records, especially in a heavy-traffic scenario. I am new to relational database stuff but have been around PHP for a while, so please bear with me here :-) I have primary and foreign keys set up correctly for the files, users, and users_files_ref tables, I'm just wondering how to manage the adding of file records for this scenario? Thanks for any help provided, it's much appreciated. -Wes

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  • SQL Server Reset Identity Increment for all tables

    - by DanSpd
    Basically I need to reset Identity Increment for all tables to its original. Here I tried some code, but it fails. http://pastebin.com/KSyvtK5b actual code from link: USE World00_Character GO -- Create a cursor to loop through the System Ojects and get each table name DECLARE TBL_CURSOR CURSOR -- Declare the SQL Statement to cursor through FOR ( SELECT Name FROM Sysobjects WHERE Type='U' ) -- Declare the @SQL Variable which will hold our dynamic sql DECLARE @SQL NVARCHAR(MAX); SET @SQL = ''; -- Declare the @TblName Variable which will hold the name of the current table DECLARE @TblName NVARCHAR(MAX); -- Open the Cursor OPEN TBL_CURSOR -- Setup the Fetch While that will loop through our cursor and set @TblName FETCH NEXT FROM TBL_CURSOR INTO @TblName -- Do this while we are not at the end of the record set WHILE (@@FETCH_STATUS <> -1) BEGIN -- Appeand this table's select count statement to our sql variable SET @SQL = @SQL + ' ( SELECT '''+@TblName+''' AS Table_Name,COUNT(*) AS Count FROM '+@TblName+' ) UNION'; -- Delete info EXEC('DBCC CHECKIDENT ('+@TblName+',RESEED,(SELECT IDENT_SEED('+@TblName+')))'); -- Pull the next record FETCH NEXT FROM TBL_CURSOR INTO @TblName -- End the Cursor Loop END -- Close and Clean Up the Cursor CLOSE TBL_CURSOR DEALLOCATE TBL_CURSOR -- Since we were adding the UNION at the end of each part, the last query will have -- an extra UNION. Lets trim it off. SET @SQL = LEFT(@SQL,LEN(@SQL)-6); -- Lets do an Order By. You can pick between Count and Table Name by picking which -- line to execute below. SET @SQL = @SQL + ' ORDER BY Count'; --SET @SQL = @SQL + ' ORDER BY Table_Name'; -- Now that our Dynamic SQL statement is ready, lets execute it. EXEC (@SQL); GO error message: Error: Msg 102, Level 15, State 1, Line 1 Incorrect syntax near '('. How can I either fix that SQL or reset identity for all tables to its original? Thank you

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  • Embedded non-relational (nosql) data store

    - by Igor Brejc
    I'm thinking about using/implementing some kind of an embedded key-value (or document) store for my Windows desktop application. I want to be able to store various types of data (GPS tracks would be one example) and of course be able to query this data. The amount of data would be such that it couldn't all be loaded into memory at the same time. I'm thinking about using sqlite as a storage engine for a key-value store, something like y-serial, but written in .NET. I've also read about FriendFeed's usage of MySQL to store schema-less data, which is a good pointer on how to use RDBMS for non-relational data. sqlite seems to be a good option because of its simplicity, portability and library size. My question is whether there are any other options for an embedded non-relational store? It doesn't need to be distributable and it doesn't have to support transactions, but it does have to be accessible from .NET and it should have a small download size. UPDATE: I've found an article titled SQLite as a Key-Value Database which compares sqlite with Berkeley DB, which is an embedded key-value store library.

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  • Storing Arbitrary Contact Information in Ruby on Rails

    - by Anthony Chivetta
    Hi, I am currently working on a Ruby on Rails app which will function in some ways like a site-specific social networking site. As part of this, each user on the site will have a profile where they can fill in their contact information (phone numbers, addresses, email addresses, employer, etc.). A simple solution to modeling this would be to have a database column per piece of information I allow users to enter. However, this seems arbitrary and limited. Further, to support allowing users to enter as many phone numbers as they would like requires the addition of another database table and joins. It seems to me that a better solution would be to serialize all the contact information entered by a user into a single field in their row. Since I will never be conditioning a SQL query on this information, such a solution wouldn't be any less efficient. Ideally, I would like to use a vCard as my serialization format. vCards are the standard solution to storing contact information across the web, and reusing tested solutions is a Good Thing. Alternative serialization formats would include simply marshaling a ruby hash, or YAML. Regardless of serialization format, supporting the reading and updating of this information in a rails-like way seems to be a major implementation challenge. So, here's the question: Has anyone seen this approach used in a rails application? Are there any rails plugins or gems that make such a system easy to implement? Ideally what I would like is an acts_as_vcard to add to my model object that would handle editing the vcard for me and saving it back to the database.

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  • Where Not In OR Except simulation of SQL in LINQ to Objects

    - by Thinking
    Suppose I have two lists that holds the list of source file names and destination file names respectively. The Sourcefilenamelist has files as 1.txt, 2.txt,3.txt, 4.txt while the Destinaitonlist has 1.txt,2.txt. I ned to write a linq query to find out which files are in SourceList that are absent in DestinationFile list. e.g. here the out put will be 3.txt and 4.txt. I have done this by a foreach statement. but now I want to do the same by using LINQ(C#). Edit: My Code is List<FileList> sourceFileNames = new List<FileList>(); sourceFileNames.Add(new FileList { fileNames = "1.txt" }); sourceFileNames.Add(new FileList { fileNames = "2.txt" }); sourceFileNames.Add(new FileList { fileNames = "3.txt" }); sourceFileNames.Add(new FileList { fileNames = "4.txt" }); List<FileList> destinationFileNames = new List<FileList>(); destinationFileNames.Add(new FileList { fileNames = "1.txt" }); destinationFileNames.Add(new FileList { fileNames = "2.txt" }); IEnumerable<FileList> except = sourceFileNames.Except(destinationFileNames); And Filelist is a simple class with only one property fileNames of type string.

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  • Communication between EJB3 Instances (JEE inter-bean communication) possible?

    - by Hank
    I'm designing a part of a JEE6 application, consisting of EJB3 beans. Part of the requirements are multiple parallel (say a few hundred) long running (over days) database hunts. Individual hunts have different search parameters (start time, end time, query filter). Parameters may get changed over time. Currently I'm thinking of the following: SearchController (Stateless Session Bean) formulates a set of search parameters, sends it off to a SearchListener via JMS SearchListener (Message Driven Bean) receives search parameters, instantiates a SearchWorker with the parameters SearchWorker (SLSB) hunts repeatedly through the database; when it finds something, the result is sent off via JMS, and the search continues; when the given 'end-time' has reached, it ends What I'm wondering now: Is there a problem, with EJB3 instances running for days? (Other than that I need to be able to deal with container restarts...) How do I know how many and which EJB instances of SearchWorker are currently running? Is it possible to communicate with them individually (similar to sending a System V signal to a unix process), e.g. to send new parameters, to end an instance, etc..

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  • Is there a good way to QuickCheck Happstack.State methods?

    - by Paul Kuliniewicz
    I have a set of Happstack.State MACID methods that I want to test using QuickCheck, but I'm having trouble figuring out the most elegant way to accomplish that. The problems I'm running into are: The only way to evaluate an Ev monad computation is in the IO monad via query or update. There's no way to create a purely in-memory MACID store; this is by design. Therefore, running things in the IO monad means there are temporary files to clean up after each test. There's no way to initialize a new MACID store except with the initialValue for the state; it can't be generated via Arbitrary unless I expose an access method that replaces the state wholesale. Working around all of the above means writing methods that only use features of MonadReader or MonadState (and running the test inside Reader or State instead of Ev. This means forgoing the use of getRandom or getEventClockTime and the like inside the method definitions. The only options I can see are: Run the methods in a throw-away on-disk MACID store, cleaning up after each test and settling for starting from initialValue each time. Write the methods to have most of the code run in a MonadReader or MonadState (which is more easily testable), and rely on a small amount of non-QuickCheck-able glue around it that calls getRandom or getEventClockTime as necessary. Is there a better solution that I'm overlooking?

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  • GPIB connection to external device using MATLAB

    - by hkf
    Is there a way to establish a GPIB connection using MATLAB without the instrument control Tool box? (I don't have it). Also is there a way for MATLAB to know what the external device's RS232 parameter values are ( Baud rate, stop bit etc..). For the RS232 connection I have the following code: % This function is meant to send commands to Potentiostat Model 263A. % A run includes turning the cell on, reading current for time t1, turning % the cell off, waiting for time t2. % t1 is the duration [secs] for which the Potentiostat must run (cell is on) % t2 is the duration [secs] to on after off % n is the number of runs % port is the serial port name such as COM1 function [s] = Potentiostat_control(t1,t2,n) port = input('type port name such as COM1', 's') s = serial(port); set(s,'BaudRate', 9600, 'DataBits', 8, 'Parity', 'even', 'StopBits', 2 ,'Terminator', 'CR/LF'); fopen(s) %fprintf(s,'RS232?') disp(['Total runs requested = ' num2str(n)]) disp('i denotes number of runs executed so far..'); for i=1:n i %data1 = query(s, '*IDN?') fprintf(s,'%s','CELL 1'); % sends the command 'CELL 1' %fprintf(s,'%s','READI'); pause(t1); fprintf(s,'%s','CELL 0'); %fprintf(s,'%s','CLEAR'); pause(t2); end fclose(s)

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  • Oracle syntax - should we have to choose between the old and the new?

    - by Martin Milan
    Hi, I work on a code base in the region of about 1'000'000 lines of source, in a team of around eight developers. Our code is basically an application using an Oracle database, but the code has evolved over time (we have plenty of source code from the mid nineties in there!). A dispute has arisen amongst the team over the syntax that we are using for querying the Oracle database. At the moment, the overwhelming majority of our queries use the "old" Oracle Syntax for joins, meaning we have code that looks like this... Example of Inner Join select customers.*, orders.date, orders.value from customers, orders where customers.custid = orders.custid Example of Outer Join select customers.custid, contacts.ContactName, contacts.ContactTelNo from customers, contacts where customers.custid = contacts.custid(+) As new developers have joined the team, we have noticed that some of them seem to prefer using SQL-92 queries, like this: Example of Inner Join select customers.*, orders.date, orders.value from customers inner join orders on (customers.custid = orders.custid) Example of Outer Join select customers.custid, contacts.ContactName, contacts.ContactTelNo from customers left join contacts on (customers.custid = contacts.custid) Group A say that everyone should be using the the "old" syntax - we have lots of code in this format, and we ought to value consistency. We don't have time to go all the way through the code now rewriting database queries, and it wouldn't pay us if we had. They also point out that "this is the way we've always done it, and we're comfortable with it..." Group B however say that they agree that we don't have the time to go back and change existing queries, we really ought to be adopting the "new" syntax on code that we write from here on in. They say that developers only really look at a single query at a time, and that so long as developers know both syntax there is nothing to be gained from rigidly sticking to the old syntax, which might be deprecated at some point in the future. Without declaring with which group my loyalties lie, I am interested in hearing the opinions of impartial observers - so let the games commence! Martin. Ps. I've made this a community wiki so as not to be seen as just blatantly chasing after question points...

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  • How to adjust size of programatically created Bitmap to match text drawn on it?

    - by TooFat
    I have the following .ashx page that takes some query string parameters and returns a bitmap with the specified text written on it. The problem I have is that I am currently just manually setting the initial size of the bitmap at 100 X 100 when what I really want is to have the bitmap be just big enough to include all the text that was written to it. How can I do this? public void ProcessRequest (HttpContext context) { context.Response.ContentType = "image/png"; string text = context.Request.QueryString["Text"]; //set FontName string fontName; if (context.Request.QueryString["FontName"] != null) { fontName = context.Request.QueryString["FontName"]; } else { fontName = "Arial"; } //Set FontSize int fontEms; if (context.Request.QueryString["FontSize"] != null) { string fontSize = context.Request.QueryString["FontSize"]; fontEms = Int32.Parse(fontSize); } else { fontEms = 12; } //Set Font Color System.Drawing.Color color; if (context.Request.QueryString["FontColor"] != null) { string fontColor = context.Request.QueryString["FontColor"]; color = System.Drawing.ColorTranslator.FromHtml(fontColor); context.Response.Write(color.ToString()); } else { color = System.Drawing.Color.Red; } using (System.Drawing.Text.PrivateFontCollection fnts = new System.Drawing.Text.PrivateFontCollection()) using (System.Drawing.FontFamily fntfam = new System.Drawing.FontFamily(fontName)) using (System.Drawing.SolidBrush brush = new System.Drawing.SolidBrush(color)) using (System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(100, 100)) { using (System.Drawing.Font fnt = new System.Drawing.Font(fntfam, fontEms)) { fnts.AddFontFile(System.IO.Path.Combine(@"C:\Development\Fonts\", fontName)); System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(bmp); graph.DrawString(text, fnt, brush, new System.Drawing.Point(0, 0)); string imgPath = System.IO.Path.Combine(@"C:\Development\MyPath\Images\Text", System.IO.Path.GetRandomFileName()); bmp.Save(imgPath); context.Response.WriteFile(imgPath); } } }

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  • t-sql most efficient row to column? for xml path, pivot

    - by ajberry
    create table _orders ( OrderId int identity(1,1) primary key nonclustered ,CustomerId int ) create table _details ( DetailId int identity(1,1) primary key nonclustered ,OrderId int ,ProductId int ) insert into _orders (CustomerId) select 1 union select 2 union select 3 insert into _details (OrderId,ProductId) select 1,100 union select 1,158 union select 1,234 union select 2,125 union select 3,105 union select 3,101 union select 3,212 union select 3,250 -- select orderid ,REPLACE(( SELECT ' ' + CAST(ProductId as varchar) FROM _details d WHERE d.OrderId = o.OrderId ORDER BY d.OrderId,d.DetailId FOR XML PATH('') ),'&#x20;','') as Products from _orders o I am looking for the most performant way to turn rows into columns. I have a requirement to output the contents of the db (not actual schema above, but concept is similar) in both fixed width and delimited formats. The above FOR XML PATH query gives me the result I want, but when dealing with anything other than small amounts of data, can take awhile. I've looked at pivot but most of the examples I have found are aggregating information. I just to combine the child rows and tack them onto the parent. For example, for an order it would need to output: OrderId,Product1,Product2,Product3,etc Thoughts or suggestions? I am using SQL Server 2k5.

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