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• Generate dynamic UPDATE command from Expression<Func<T, T>>

  - by Rui Jarimba

  I'm trying to generate an UPDATE command based on Expression trees (for a batch update). Assuming the following UPDATE command: UPDATE Product SET ProductTypeId = 123, ProcessAttempts = ProcessAttempts + 1 For an expression like this: Expression<Func<Product, Product>> updateExpression = entity => new Product() { ProductTypeId = 123, ProcessAttempts = entity.ProcessAttempts + 1 }; How can I generate the SET part of the command? SET ProductTypeId = 123, ProcessAttempts = ProcessAttempts + 1

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• C# expression tree for ordinary code

  - by rwallace

  It's possible to create an expression tree, if you declare it as such. But is it possible to get an expression tree for an ordinary chunk of code such as a method or property getter? What I'm trying to do is, let's say for an order processing system, I have a class for order items: class Item : Entity { [Cascade] public Document document { get; set; } public int line { get; set; } public Product product { get; set; } public string description { get; set; } public decimal qty { get; set; } public decimal price { get; set; } public decimal net { get { return qty * price; } } public VatCode vat_code { get; set; } } where the net value equals qty * price, so I'd like to declare it as such, either with a property or method, and then also have the framework introspect that expression so it can generate appropriate SQL for defining a corresponding calculated column in a corresponding database view. The most obvious way to do this would be to get the expression tree for a property getter or a method, but I can't find any indication how to do this, or that it is possible. (I have found a way to get a method body as a byte stream, but that's not what's desired here.) If that isn't possible, I suppose the recommended solution would be to declare something like a static field that is an expression tree, and compile/run it at run time for internal use, and also introspect as normal for SQL generation?

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• Using Entity Framework Table splitting customisations in an ASP.Net application

  - by nikolaosk

  I have been teaching in the past few weeks many people on how to use Entity Framework. I have decided to provide some of the samples I am using in my classes. First let’s try to define what EF is and why it is going to help us to create easily data-centric applications.Entity Framework is an object-relational mapping (ORM) framework for the .NET Framework.EF addresses the problem of Object-relational impedance mismatch . I will not be talking about that mismatch because it is well documented in many...(read more)

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• GNU/Linux interactive table content GUI editor?

  - by sdaau

  I often find myself in the need to gather data (say from the internet), into a table, for comparison reasons. I usually need the final table output in HTML or MediaWiki mostly, but often times also Latex. My biggest problem is that I often forget the correct table syntax for these markup languages, as well as what needs to be properly escaped in the inline data, for the table to render correctly. So, I often wish there was a GUI application, which provides a tabular framework - which I could stick "Always on Top" as a desktop window, and I could paste content into specific cells - before finally exporting the table as a code in the correct language. One application that partially allows this is Open/LibreOffice calc: The good thing here is that: I can drag and drop browser content into a specifically targeted table cell (here B2) "Rich" text / HTML code gets pasted For long content, the cell (column) width stays put as it originally was The bad thing is, that: when the cell height (due to content size) becomes larger than the calc window, it becomes nearly impossible to scroll calc contents up and down (at least with the mousewheel), as the view gets reset to top-right corner of the selected cell calc shows an "endless"/unlimited field of cells, so not exactly a "table" - which I find visually very confusing (and cognitively taxing) Can only export table to HTML What I would need is an application that: Allows for a limited size table, but with quick adding of rows and columns (e.g. via corresponding + buttons) Allows for quick setup of row and column height and width (as well as table size) Stays put at those sizes, regardless of size of content pasted in; if cell content overflows, cell scrollbars are shown (cell content could be possibly re-edited in a separate/new window); if table overflows over window size, window scrollbars are shown Exports table in multiple formats (I'd need both HTML and mediawiki), properly escaping cell content for each (possibility to strip HTML tags from content pasted in cells, to get plain text, is a plus) Targeting a specific cell in the table for the content paste operation is a must - it doesn't have to be drag'n'drop though, a right click over a cell with "Paste content" is enough. I'd also want the ability to click in a specific cell and type in (plain text) content immediately. So, my question is: is there an application out there that already does something like this? The reason I'm asking is that - as the screenshots show - for instance Libre/OpenOffice allows it, but only somewhat (as using it for that purpose is tedious). I know there exist some GUI editors for Linux (both for UI like guile or HTML like amaya); but I don't know them enough to pinpoint if any of them would offer this kind of functionality (and at least in my searches, that kind of functionality, if present in diverse software, seems not to be advertised). Note I'm not interested in styling an HTML table, which is why I haven't used "table designer" in the title, but "table editor" (in lack of better terms) - I'm interested in (quickly) adjusting row/column size of the table, and populating it with pasted data (which is possibly HTML) in a GUI; and finally exporting such a table as self-contained HTML (or other) code.

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• Sorting table data across two table sets with jquery tablesorter

  - by Peter

  I am using jquery table sorter and have two tables. Instead of sorting the data just in the first table, could there be a way to combine the data in the second table and sort both? As an example, sorting column 1 on table 1 OR 2, will result in: //ORIGINAL //RESULT TABLE 1 TABLE 1 col1 | col2 col1 | col2 1 | 1 1 | 1 3 | 3 2 | 2 5 | 5 3 | 3 TABLE 2 TABLE 2 col1 | col 2 col1 | col 2 2 | 2 4 | 4 4 | 4 5 | 5 6 | 6 6 | 6

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• "Error in the Site Data Web Service." when performing crawl

  - by Janis Veinbergs

  Installed SharePoint Services v3 (SP2, october 2009 cumulative updates, Language Pack), attached to a content database I had previously (all works). Installed Search server 2008 Express (with language pack) on top of WSS and crawl does not work. However it works for newly created web application + database. Was playing around with accounts, permissions to try get it working. Currently I have WSS_Crawler account with such permissions: Office Search Server runs with WSS_Crawler account Config database has read permissions for WSS_Crawler Content database has read permissions for WSS_Crawler WSS_Crawler is owner of search database. Added WSS_Crawler to SQL server browser user group and administrator Yes, i'v given more permissions than needed, but it doesn't even work with that and i don't know if its permission problem or what. Crawl log says there is Error in the Site Data Web Service., nothing more. There were known issues with a similar error: Error in the Site Data Web Service. (Value does not fall within the expected range.), but this is not the case as thats an old issue and i hope it has been included in SP2... Logs are from olders to newest (descending order). They don't appear to be very helpful. Crawl log http://serveris Crawled Local Office SharePoint Server sites 3/15/2010 9:39 AM sts3://serveris Crawled Local Office SharePoint Server sites 3/15/2010 9:39 AM sts3://serveris/contentdbid={55180cfa-9d2d-46e4... Crawled Local Office SharePoint Server sites 3/15/2010 9:39 AM http://serveris/test Error in the Site Data Web Service. Local Office SharePoint Server sites 3/15/2010 9:39 AM http://serveris Error in the Site Data Web Service. Local Office SharePoint Server sites 3/15/2010 9:39 AM EventLog No errors in EventLog, just some Information events that Office Server Search provides The search service started. Successfully stored the application configuration registry snapshot in the database. Context: Application 'SharedServices Component: da1288b2-4109-4219-8c0c-3a22802eb842 Catalog: Portal_Content. A master merge was started due to an external request. Component: da1288b2-4109-4219-8c0c-3a22802eb842 A master merge has completed for catalog Portal_Content. Component: da1288b2-4109-4219-8c0c-3a22802eb842 Catalog: AnchorProject. A master merge was started due to an external request. Component: da1288b2-4109-4219-8c0c-3a22802eb842 A master merge has completed for catalog AnchorProject. ULS Log Just some information, but no exceptions, unexpected errors 03/15/2010 09:03:28.28 mssearch.exe (0x1B2C) 0x0E8C Search Server Common GatherStatus 0 Monitorable Insert crawl 771 to inprogress queue hr 0x00000000 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:6591 03/15/2010 09:03:28.28 mssearch.exe (0x1B2C) 0x0E8C Search Server Common GatherStatus 0 Monitorable Request Start Crawl 1, project Portal_Content, crawl 771 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2875 03/15/2010 09:03:28.28 mssearch.exe (0x1B2C) 0x0E8C Search Server Common GatherStatus 0 Monitorable Advise status change 1, project Portal_Content, crawl 771 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:28.28 w3wp.exe (0x1D98) 0x0958 Search Server Common MS Search Administration 8wn6 Information A full crawl was started on 'Local Office SharePoint Server sites' by BALTICOVO\janis.veinbergs. 03/15/2010 09:03:28.43 mssdmn.exe (0x1750) 0x10F8 ULS Logging Unified Logging Service 8wsv High ULS Init Completed (mssdmn.exe, Microsoft.Office.Server.Native.dll) 03/15/2010 09:03:30.48 mssdmn.exe (0x1750) 0x09C0 Search Server Common MS Search Indexing 8z0v Medium Create CCache 03/15/2010 09:03:30.56 mssdmn.exe (0x1750) 0x09C0 Search Server Common MS Search Indexing 8z0z Medium Create CUserCatalogCache 03/15/2010 09:03:32.06 w3wp.exe (0x1D98) 0x0958 Search Server Common MS Search Administration 90ge Medium SQL: dbo.proc_MSS_PropagationGetQueryServers 03/15/2010 09:03:32.09 w3wp.exe (0x1D98) 0x0958 Search Server Common MS Search Administration 7phq High GetProtocolConfigHelper failed in GetNotesInterface(). 03/15/2010 09:03:34.26 mssearch.exe (0x1B2C) 0x16A4 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project Portal_Content, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:35.92 mssearch.exe (0x1B2C) 0x16A4 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project Portal_Content, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:37.32 mssearch.exe (0x1B2C) 0x16A4 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project Portal_Content, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:37.23 mssdmn.exe (0x1750) 0x1850 Search Server Common MS Search Indexing 8z14 Medium Test TRACE (NULL):(null), (NULL)(null), (CrLf): , end 03/15/2010 09:03:39.04 mssearch.exe (0x1B2C) 0x16A4 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project Portal_Content, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:40.98 mssdmn.exe (0x1750) 0x0B24 Search Server Common MS Search Indexing 7how Monitorable GetWebDefaultPage fail. error 2147755542, strWebUrl http://serveris 03/15/2010 09:03:41.87 mssdmn.exe (0x1750) 0x1260 Search Server Common PHSts 0 Monitorable CSTS3Accessor::GetSubWebListItemAccessURL GetAccessURL failed: Return error to caller, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3acc.cxx Line:505 03/15/2010 09:03:41.87 mssdmn.exe (0x1750) 0x1260 Search Server Common PHSts 0 Monitorable CSTS3Accessor::Init: GetSubWebListItemAccessURL failed. Return error to caller, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3acc.cxx Line:348 03/15/2010 09:03:41.87 mssdmn.exe (0x1750) 0x1260 Search Server Common PHSts 0 Monitorable CSTS3Accessor::Init fails, Url sts3://serveris/siteurl=test/siteid={390611b2-55f3-4a99-8600-778727177a28}/weburl=/webid={fb0e4bff-65d5-4ded-98d5-fd099456962b}, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3handler.cxx Line:243 03/15/2010 09:03:41.87 mssdmn.exe (0x1750) 0x1260 Search Server Common PHSts 0 Monitorable CSTS3Handler::CreateAccessorExB: Return error to caller, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3handler.cxx Line:261 03/15/2010 09:03:40.98 mssdmn.exe (0x1750) 0x1260 Search Server Common MS Search Indexing 7how Monitorable GetWebDefaultPage fail. error 2147755542, strWebUrl http://serveris/test 03/15/2010 09:03:41.90 mssdmn.exe (0x1750) 0x0B24 Search Server Common PHSts 0 Monitorable CSTS3Accessor::GetSubWebListItemAccessURL GetAccessURL failed: Return error to caller, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3acc.cxx Line:505 03/15/2010 09:03:41.90 mssdmn.exe (0x1750) 0x0B24 Search Server Common PHSts 0 Monitorable CSTS3Accessor::Init: GetSubWebListItemAccessURL failed. Return error to caller, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3acc.cxx Line:348 03/15/2010 09:03:41.90 mssdmn.exe (0x1750) 0x0B24 Search Server Common PHSts 0 Monitorable CSTS3Accessor::Init fails, Url sts3://serveris/siteurl=/siteid={505443fa-ef12-4f1e-a04b-d5450c939b78}/weburl=/webid={c5a4f8aa-9561-4527-9e1a-b3c23200f11c}, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3handler.cxx Line:243 03/15/2010 09:03:41.90 mssdmn.exe (0x1750) 0x0B24 Search Server Common PHSts 0 Monitorable CSTS3Handler::CreateAccessorExB: Return error to caller, hr=80042616 - File:d:\office\source\search\search\gather\protocols\sts3\sts3handler.cxx Line:261 03/15/2010 09:03:43.26 mssearch.exe (0x1B2C) 0x0750 Search Server Common GatherStatus 0 Monitorable Advise status change 24, project Portal_Content, crawl 771 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:43.26 mssearch.exe (0x1B2C) 0x1804 Search Server Common GatherStatus 0 Monitorable Remove crawl 771 from inprogress queue - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:6722 03/15/2010 09:03:43.26 mssearch.exe (0x1B2C) 0x0750 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project Portal_Content, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:44.65 mssearch.exe (0x1B2C) 0x1804 Search Server Common GatherStatus 0 Monitorable Insert crawl 772 to inprogress queue hr 0x00000000 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:6591 03/15/2010 09:03:44.65 mssearch.exe (0x1B2C) 0x1804 Search Server Common GatherStatus 0 Monitorable Request Start Crawl 0, project AnchorProject, crawl 772 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2875 03/15/2010 09:03:44.65 mssearch.exe (0x1B2C) 0x1804 Search Server Common GatherStatus 0 Monitorable Advise status change 0, project AnchorProject, crawl 772 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:44.65 mssearch.exe (0x1B2C) 0x1804 Search Server Common GatherStatus 0 Monitorable Unlock Queue, project Portal_Content - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2922 03/15/2010 09:03:44.82 mssearch.exe (0x1B2C) 0x1DD0 Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:44.95 mssearch.exe (0x1B2C) 0x0750 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project AnchorProject, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:46.51 mssearch.exe (0x1B2C) 0x0750 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project AnchorProject, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:46.39 mssearch.exe (0x1B2C) 0x1E4C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.01 mssearch.exe (0x1B2C) 0x1C6C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.87 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.29 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.53 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.67 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.82 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.84 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.89 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:49.90 mssearch.exe (0x1B2C) 0x0750 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project AnchorProject, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:51.42 mssearch.exe (0x1B2C) 0x1E4C Search Server Common GatherStatus 0 Monitorable Advise status change 4, project AnchorProject, crawl 772 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:51.00 mssearch.exe (0x1B2C) 0x1E4C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:51.42 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GatherStatus 0 Monitorable Remove crawl 772 from inprogress queue - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:6722 03/15/2010 09:03:52.96 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GatherStatus 0 Monitorable Insert crawl 773 to inprogress queue hr 0x00000000 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:6591 03/15/2010 09:03:52.96 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GatherStatus 0 Monitorable Request Start Crawl 0, project AnchorProject, crawl 773 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2875 03/15/2010 09:03:55.29 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GatherStatus 0 Monitorable Unlock Queue, project AnchorProject - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2922 03/15/2010 09:03:55.29 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GatherStatus 0 Monitorable Removed start crawl request from Queue 0, crawl 773 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2942 03/15/2010 09:03:55.29 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GatherStatus 0 Monitorable Request Start Crawl 0, project AnchorProject, crawl 773 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2875 03/15/2010 09:03:55.29 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GatherStatus 0 Monitorable Advise status change 0, project AnchorProject, crawl 773 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:55.37 mssearch.exe (0x1B2C) 0x1CCC Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:55.37 mssearch.exe (0x1B2C) 0x0750 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project AnchorProject, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:56.71 mssearch.exe (0x1B2C) 0x1E4C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:56.78 mssearch.exe (0x1B2C) 0x0750 Search Server Common GatherStatus 0 Monitorable Advise status change 12, project AnchorProject, crawl -1 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:58.40 mssearch.exe (0x1B2C) 0x155C Search Server Common GathererSql 0 Monitorable CGatherer::LoadTransactionsFromCrawlInternal Flush anchor, count 0 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4943 03/15/2010 09:03:58.89 mssearch.exe (0x1B2C) 0x155C Search Server Common GatherStatus 0 Monitorable Advise status change 4, project AnchorProject, crawl 773 - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:4853 03/15/2010 09:03:58.89 mssearch.exe (0x1B2C) 0x1130 Search Server Common GatherStatus 0 Monitorable Remove crawl 773 from inprogress queue - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:6722 03/15/2010 09:03:58.89 mssearch.exe (0x1B2C) 0x1130 Search Server Common GatherStatus 0 Monitorable Unlock Queue, project AnchorProject - File:d:\office\source\search\search\gather\server\gatherobj.cxx Line:2922 What could be wrong here - any clues?

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• Why not port Linux kernel to Common Lisp?

  - by rplevy

  Conventional wisdom states that OS kernels must be written in C in order to achieve the necessary levels of performance. This has been the justification for not using more expressive high level languages. However, for a few years now implementations of Common Lisp such as SBCL have proven to be just as performant as C. What then are the arguments against redoing the kernel in a powerfully expressive language, namely Common Lisp? I don't think anyone (at least anyone who knows what they are talking about) could argue against the fact that the benefits in transparency and readability would be tremendous, not to mention all the things that can't be done in C that can be done in Lisp, but there may be implementation details that would make this a bad idea.

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• How to use Common Table Expression and check no duplication in sqlserver

  - by vodkhang

  I have a table references to itself. User table: id, username, managerid and managerid links back to id Now, I want to get all the managers including direct manager, manager of direct manager, so on and so forth... The problem is that I do not want to have a unstop recursive sql. So, I want to check if an id alreay in a list, I will not include it anymore. Here is my sql for that: with --the relation for all the subparts of ozsolar including itself all_managers (id, username, managerid, idlist) as ( --seed that is the ozsola part select u1.id, u1.username, u1.managerid, ' ' from users u1, users u2 where u1.id = u2.managerid and u2.id = 6 UNION ALL select u.id, u.username, u.managerid, idlist + ' ' + u.id from all_managers a, users u where a.managerid = u.id and charindex(cast(u.id as nvarchar(5)), idlist) != 0 ) --select the total number of subparts and group by subpart select id, username from all_managers; The problem is that in this line: select u1.id, u1.username, u1.managerid, ' ' The sqlserver complains with me that I can not put ' ' as the initialized for idlist. nvarchar(40) does not work as well. I do not know how to declare it inside a common table expression like this one. Usually, in db2, I can just put varchar(40)

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• Connecting .NET to Common Lisp

  - by JPanest

  I have a fairly involved LispWorks Common Lisp module that sits atop some .NET modules via RDNZL. It has come up that I need to expose some of its functionality to some other .NET applications, and I'm not sure the best (shortest) way to approach this without re-writing the module in C#. I know there are a few CLR Lisp implementations but most seem unmaintained or incomplete and there are many things that cannot be trivially re-written in Scheme. Is there any facility that exposes the opposite of what RDNZL enables (.NET - Common Lisp)? Can I use RDNZL to deliver a DLL that accepts .NET objects?

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• pivot table / chart default sorting

  - by Prince Charming

  What is default sorting for excel 2010 pivot table and charts I have a "Year month Week" column in my data sheet which I am using as row label, excel pivot table renders it arbitrarily like in data sheet I have data in the following order 2010 October Week 1 2010 September Week 1 2010 September Week 2 2010 September Week 3 2010 September Week 4 but when I use this in pivot table it generates row labels as 2010 October Week 1 2010 September Week 3 2010 September Week 2 2010 September Week 4 2010 September Week 1 I want pivot table to show row labels exactly in the same order as it is in data sheet

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• SQL Server Table Polling by Multiple Subscribers

  - by Daniel Hester

  Background Designing Stored Procedures that are safe for multiple subscribers (to call simultaneously) can be challenging.  For example let’s say that you want multiple worker processes to poll a shared work queue that’s encapsulated as a SQL Table. This is a common scenario and through experience you’ll find that you want to use Table Hints to prevent unwanted locking when performing simultaneous queries on the same table. There are three table hints to consider: NOLOCK, READPAST and UPDLOCK. Both NOLOCK and READPAST table hints allow you to SELECT from a table without placing a LOCK on that table. However, SELECTs with the READPAST hint will ignore any records that are locked due to being updated/inserted (or otherwise “dirty”), whereas a SELECT with NOLOCK ignores all locks including dirty reads. For the initial update of the flag (that marks the record as available for subscription) I don’t use the NOLOCK Table Hint because I want to be sensitive to the “active” records in the table and I want to exclude them.  I use an Update Lock (UPDLOCK) in conjunction with a WHERE clause that uses a sub-select with a READPAST Table Hint in order to explicitly lock the records I’m updating (UPDLOCK) but not place a lock on the table when selecting the records that I’m going to update (READPAST). UPDATES should be allowed to lock the rows affected because we’re probably changing a flag on a record so that it is not included in a SELECT from another subscriber. On the UPDATE statement we should explicitly use the UPDLOCK to guard against lock escalation. A SELECT to check for the next record(s) to process can result in a shared read lock being held by more than one subscriber polling the shared work queue (SQL table). It is expected that more than one worker process (or server) might try to process the same new record(s) at the same time. When each process then tries to obtain the update lock, none of them can because another process has a shared read lock in place. Thus without the UPDLOCK hint the result would be a lock escalation deadlock; however with the UPDLOCK hint this condition is mitigated against. Note that using the READPAST table hint requires that you also set the ISOLATION LEVEL of the transaction to be READ COMMITTED (rather than the default of SERIALIZABLE). Guidance In the Stored Procedure that returns records to the multiple subscribers: Perform the UPDATE first. Change the flag that makes the record available to subscribers.  Additionally, you may want to update a LastUpdated datetime field in order to be able to check for records that “got stuck” in an intermediate state or for other auditing purposes. In the UPDATE statement use the (UPDLOCK) Table Hint on the UPDATE statement to prevent lock escalation. In the UPDATE statement also use a WHERE Clause that uses a sub-select with a (READPAST) Table Hint to select the records that you’re going to update. In the UPDATE statement use the OUTPUT clause in conjunction with a Temporary Table to isolate the record(s) that you’ve just updated and intend to return to the subscriber. This is the fastest way to update the record(s) and to get the records’ identifiers within the same operation. Finally do a set-based SELECT on the main Table (using the Temporary Table to identify the records in the set) with either a READPAST or NOLOCK table hint.  Use NOLOCK if there are other processes (besides the multiple subscribers) that might be changing the data that you want to return to the multiple subscribers; or use READPAST if you're sure there are no other processes (besides the multiple subscribers) that might be updating column data in the table for other purposes (e.g. changes to a person’s last name).  NOLOCK is generally the better fit in this part of the scenario. See the following as an example: CREATE PROCEDURE [dbo].[usp_NewCustomersSelect] AS BEGIN -- OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON -- DECLARE TEMP TABLE -- Note that this example uses CustomerId as an identifier; -- you could just use the Identity column Id if that’s all you need. DECLARE @CustomersTempTable TABLE ( CustomerId NVARCHAR(255) ) -- PERFORM UPDATE FIRST -- [Customers] is the name of the table -- [Id] is the Identity Column on the table -- [CustomerId] is the business document key used to identify the -- record globally, i.e. in other systems or across SQL tables -- [Status] is INT or BIT field (if the status is a binary state) -- [LastUpdated] is a datetime field used to record the time of the -- last update UPDATE [Customers] WITH (UPDLOCK) SET [Status] = 1, [LastUpdated] = GETDATE() OUTPUT [INSERTED].[CustomerId] INTO @CustomersTempTable WHERE ([Id] = (SELECT TOP 100 [Id] FROM [Customers] WITH (READPAST) WHERE ([Status] = 0) ORDER BY [Id] ASC)) -- PERFORM SELECT FROM ENTITY TABLE SELECT [C].[CustomerId], [C].[FirstName], [C].[LastName], [C].[Address1], [C].[Address2], [C].[City], [C].[State], [C].[Zip], [C].[ShippingMethod], [C].[Id] FROM [Customers] AS [C] WITH (NOLOCK), @CustomersTempTable AS [TEMP] WHERE ([C].[CustomerId] = [TEMP].[CustomerId]) END In a system that has been designed to have multiple status values for records that need to be processed in the Work Queue it is necessary to have a “Watch Dog” process by which “stale” records in intermediate states (such as “In Progress”) are detected, i.e. a [Status] of 0 = New or Unprocessed; a [Status] of 1 = In Progress; a [Status] of 2 = Processed; etc.. Thus, if you have a business rule that states that the application should only process new records if all of the old records have been processed successfully (or marked as an error), then it will be necessary to build a monitoring process to detect stalled or stale records in the Work Queue, hence the use of the LastUpdated column in the example above. The Status field along with the LastUpdated field can be used as the criteria to detect stalled / stale records. It is possible to put this watchdog logic into the stored procedure above, but I would recommend making it a separate monitoring function. In writing the stored procedure that checks for stale records I would recommend using the same kind of lock semantics as suggested above. The example below looks for records that have been in the “In Progress” state ([Status] = 1) for greater than 60 seconds: CREATE PROCEDURE [dbo].[usp_NewCustomersWatchDog] AS BEGIN -- TO OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON DECLARE @MaxWait int; SET @MaxWait = 60 IF EXISTS (SELECT 1 FROM [dbo].[Customers] WITH (READPAST) WHERE ([Status] = 1) AND (DATEDIFF(s, [LastUpdated], GETDATE()) > @MaxWait)) BEGIN SELECT 1 AS [IsWatchDogError] END ELSE BEGIN SELECT 0 AS [IsWatchDogError] END END Downloads The zip file below contains two SQL scripts: one to create a sample database with the above stored procedures and one to populate the sample database with 10,000 sample records.  I am very grateful to Red-Gate software for their excellent SQL Data Generator tool which enabled me to create these sample records in no time at all. References http://msdn.microsoft.com/en-us/library/ms187373.aspx http://www.techrepublic.com/article/using-nolock-and-readpast-table-hints-in-sql-server/6185492 http://geekswithblogs.net/gwiele/archive/2004/11/25/15974.aspx http://grounding.co.za/blogs/romiko/archive/2009/03/09/biztalk-sql-receive-location-deadlocks-dirty-reads-and-isolation-levels.aspx

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• MySQL foreign key creation with alter table command

  - by user313338

  I created some tables using MySQL Workbench, and then did forward ‘forward engineer’ to create scripts to create these tables. BUT, the scripts lead me to a number of problems. One of which involves the foreign keys. So I tried creating separate foreign key additions using alter table and I am still getting problems. The code is below (the set statements, drop/create statements I left in … though I don’t think they should matter for this): SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0; SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0; SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL'; DROP SCHEMA IF EXISTS `mydb` ; CREATE SCHEMA IF NOT EXISTS `mydb` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci ; -- ----------------------------------------------------- -- Table `mydb`.`User` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User` ; CREATE TABLE IF NOT EXISTS `mydb`.`User` ( `UserName` VARCHAR(35) NOT NULL , `Num_Accts` INT NOT NULL , `Password` VARCHAR(45) NULL , `Email` VARCHAR(45) NULL , `User_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_ID`) ) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `mydb`.`User_Space` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User_Space` ; CREATE TABLE IF NOT EXISTS `mydb`.`User_Space` ( `User_UserName` VARCHAR(35) NOT NULL , `User_Space_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_Space_ID`), FOREIGN KEY (`User_UserName`) REFERENCES `mydb`.`User` (`UserName`) ON UPDATE CASCADE ON DELETE CASCADE) ENGINE = InnoDB; SET SQL_MODE=@OLD_SQL_MODE; SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS; SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS; The error this produces is: Error Code: 1005 Can't create table 'mydb.user_space' (errno: 150) Anybody know what the heck I’m doing wrong?? And anybody else have problems with the script generation done by mysql workbench? It’s a nice tool, but annoying that it pumps out scripts that don’t work for me. [As an fyi here’s the script it auto-generates: SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0; SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0; SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL'; DROP SCHEMA IF EXISTS `mydb` ; CREATE SCHEMA IF NOT EXISTS `mydb` DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci ; -- ----------------------------------------------------- -- Table `mydb`.`User` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User` ; CREATE TABLE IF NOT EXISTS `mydb`.`User` ( `UserName` VARCHAR(35) NOT NULL , `Num_Accts` INT NOT NULL , `Password` VARCHAR(45) NULL , `Email` VARCHAR(45) NULL , `User_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_ID`) ) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `mydb`.`User_Space` -- ----------------------------------------------------- DROP TABLE IF EXISTS `mydb`.`User_Space` ; CREATE TABLE IF NOT EXISTS `mydb`.`User_Space` ( `User_Space_ID` INT NOT NULL AUTO_INCREMENT , PRIMARY KEY (`User_Space_ID`) , INDEX `User_ID` () , CONSTRAINT `User_ID` FOREIGN KEY () REFERENCES `mydb`.`User` () ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; SET SQL_MODE=@OLD_SQL_MODE; SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS; SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS; ** Thanks!]

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• "select * into table" Will it work for inserting data into existing table

  - by Shantanu Gupta

  I am trying to insert data from one of my existing table into another existing table. Is it possible to insert data into any existing table using select * into query. I think it can be done using union but in that case i need to record all data of my existing table into temporary table, then drop that table and finally than apply union to insert all records into same table eg. select * into #tblExisting from tblExisting drop table tblExisting select * into tblExisting from #tblExisting union tblActualData Here tblExisting is the table where I actually want to store all data tblActualData is the table from where data is to be appended to tblExisting. Is it right method. Do we have some other alternative ?

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• What would be the safest way to store objects of classes derived from a common interface in a common

  - by Svenstaro

  I'd like to manage a bunch of objects of classes derived from a shared interface class in a common container. To illustrate the problem, let's say I'm building a game which will contain different actors. Let's call the interface IActor and derive Enemy and Civilian from it. Now, the idea is to have my game main loop be able to do this: // somewhere during init std::vector<IActor> ActorList; Enemy EvilGuy; Civilian CoolGuy; ActorList.push_back(EvilGuy); ActorList.push_back(CoolGuy); and // main loop while(!done) { BOOST_FOREACH(IActor CurrentActor, ActorList) { CurrentActor.Update(); CurrentActor.Draw(); } } ... or something along those lines. This example obviously won't work but that is pretty much the reason I'm asking here. I'd like to know: What would be the best, safest, highest-level way to manage those objects in a common heterogeneous container? I know about a variety of approaches (Boost::Any, void*, handler class with boost::shared_ptr, Boost.Pointer Container, dynamic_cast) but I can't decide which would be the way to go here. Also I'd like to emphasize that I want to stay away as far as possible from manual memory management or nested pointers. Help much appreciated :).

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• MySQL ALTER TABLE on very large table - is it safe to run it?

  - by Timothy Mifsud

  I have a MySQL database with one particular MyISAM table of above 4 million rows. I update this table about once a week with about 2000 new rows. After updating, I then perform the following statement: ALTER TABLE x ORDER BY PK DESC i.e. I order the table in question by the primary key field in descending order. This has not given me any problems on my development machine (Windows with 3GB memory), but, even though 3 times I have tried it successfully on the production Linux server (with 512MB RAM - and achieving the resulted sorted table in about 6 minutes each time), the last time I tried it I had to stop the query after about 30 minutes and rebuild the database from a backup. I have started to wonder whether a 512MB server can cope with that statement (on such a large table) as I have read that a temporary table is created to perform the ALTER TABLE command?! And, if it can be safely run, what should be the expected time for the alteration of the table? Thanks in advance, Tim

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• Building extensions for Expression Blend 4 using MEF

  - by Timmy Kokke

  Introduction Although it was possible to write extensions for Expression Blend and Expression Design, it wasn’t very easy and out of the box only one addin could be used. With Expression Blend 4 it is possible to write extensions using MEF, the Managed Extensibility Framework. Until today there’s no documentation on how to build these extensions, so look thru the code with Reflector is something you’ll have to do very often. Because Blend and Design are build using WPF searching the visual tree with Snoop and Mole belong to the tools you’ll be using a lot exploring the possibilities.  Configuring the extension project Extensions are regular .NET class libraries. To create one, load up Visual Studio 2010 and start a new project. Because Blend is build using WPF, choose a WPF User Control Library from the Windows section and give it a name and location. I named mine DemoExtension1. Because Blend looks for addins named *.extension.dll  you’ll have to tell Visual Studio to use that in the Assembly Name. To change the Assembly Name right click your project and go to Properties. On the Application tab, add .Extension to name already in the Assembly name text field. To be able to debug this extension, I prefer to set the output path on the Build tab to the extensions folder of Expression Blend. This means that everything that used to go into the Debug folder is placed in the extensions folder. Including all referenced assemblies that have the copy local property set to false. One last setting. To be able to debug your extension you could start Blend and attach the debugger by hand. I like it to be able to just hit F5. Go to the Debug tab and add the the full path to Blend.exe in the Start external program text field. Extension Class Add a new class to the project.  This class needs to be inherited from the IPackage interface. The IPackage interface can be found in the Microsoft.Expression.Extensibility namespace. To get access to this namespace add Microsoft.Expression.Extensibility.dll to your references. This file can be found in the same folder as the (Expression Blend 4 Beta) Blend.exe file. Make sure the Copy Local property is set to false in this reference. After implementing the interface the class would look something like: using Microsoft.Expression.Extensibility; namespace DemoExtension1 { public class DemoExtension1:IPackage { public void Load(IServices services) { } public void Unload() { } } } These two methods are called when your addin is loaded and unloaded. The parameter passed to the Load method, IServices services, is your main entry point into Blend. The IServices interface exposes the GetService<T> method. You will be using this method a lot. Almost every part of Blend can be accessed thru a service. For example, you can use to get to the commanding services of Blend by calling GetService<ICommandService>() or to get to the Windowing services by calling GetService<IWindowService>(). To get Blend to load the extension we have to implement MEF. (You can get up to speed on MEF on the community site or read the blog of Mr. MEF, Glenn Block.)  In the case of Blend extensions, all that needs to be done is mark the class with an Export attribute and pass it the type of IPackage. The Export attribute can be found in the System.ComponentModel.Composition namespace which is part of the .NET 4 framework. You need to add this to your references. using System.ComponentModel.Composition; using Microsoft.Expression.Extensibility;   namespace DemoExtension1 { [Export(typeof(IPackage))] public class DemoExtension1:IPackage { Blend is able to find your addin now. Adding UI The addin doesn’t do very much at this point. The WPF User Control Library came with a UserControl so lets use that in this example. I just drop a Button and a TextBlock onto the surface of the control to have something to show in the demo. To get the UserControl to work in Blend it has to be registered with the WindowService.  Call GetService<IWindowService>() on the IServices interface to get access to the windowing services. The UserControl will be used in Blend on a Palette and has to be registered to enable it. This is done by calling the RegisterPalette on the IWindowService interface and passing it an identifier, an instance of the UserControl and a caption for the palette. public void Load(IServices services) { IWindowService windowService = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(); windowService.RegisterPalette("DemoExtension", uc, "Demo Extension"); } After hitting F5 to start debugging Expression Blend will start. You should be able to find the addin in the Window menu now. Activating this window will show the “Demo Extension” palette with the UserControl, style according to the settings of Blend. Now what? Because little is publicly known about how to access different parts of Blend adding breakpoints in Debug mode and browsing thru objects using the Quick Watch feature of Visual Studio is something you have to do very often. This demo extension can be used for that purpose very easily. Add the click event handler to the button on the UserControl. Change the contructor to take the IServices interface and store this in a field. Set a breakpoint in the Button_Click method. public partial class UserControl1 : UserControl { private readonly IServices _services;   public UserControl1(IServices services) { _services = services; InitializeComponent(); }   private void button1_Click(object sender, RoutedEventArgs e) { } } Change the call to the constructor in the load method and pass it the services property. public void Load(IServices services) { IWindowService service = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(services); service.RegisterPalette("DemoExtension", uc, "Demo Extension"); } Hit F5 to compile and start Blend. Got to the window menu and start show the addin. Click on  the button to hit the breakpoint. Now place the carrot text _services text in the code window and hit Shift+F9 to show the Quick Watch window. Now start exploring and discovering where to find everything you need.  More Information The are no official resources available yet. Microsoft has released one extension for expression Blend that is very useful as a reference, the Microsoft Expression Blend® Add-in Preview for Windows® Phone. This will install a .extension.dll file in the extension folder of Blend. You can load this file with Reflector and have a peek at how Microsoft is building his addins. Conclusion I hope this gives you something to get started building extensions for Expression Blend. Until Microsoft releases the final version, which hopefully includes more information about building extensions, we’ll have to work on documenting it in the community.

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• Call asp.net mvc Html Helper within custom html helper with expression parameter

  - by Frank Michael Kraft

  I am trying to write an html helper extension within the asp.net mvc framework. public static MvcHtmlString PlatformNumericTextBoxFor<TModel>(this HtmlHelper instance, TModel model, Expression<Func<TModel,double>> selector) where TModel : TableServiceEntity { var viewModel = new PlatformNumericTextBox(); var func = selector.Compile(); MemberExpression memExpession = (MemberExpression)selector.Body; string name = memExpession.Member.Name; var message = instance.ValidationMessageFor<TModel, double>(selector); viewModel.name = name; viewModel.value = func(model); viewModel.validationMessage = String.Empty; var result = instance.Partial(typeof(PlatformNumericTextBox).Name, viewModel); return result; } The line var message = instance.ValidationMessageFor<TModel, double>(selector); has a syntax error. But I do not understand it. The error is: Fehler 2 "System.Web.Mvc.HtmlHelper" enthält keine Definition für "ValidationMessageFor", und die Überladung der optimalen Erweiterungsmethode "System.Web.Mvc.Html.ValidationExtensions.ValidationMessageFor(System.Web.Mvc.HtmlHelper, System.Linq.Expressions.Expression)" weist einige ungültige Argumente auf. C:\Projects\WorkstreamPlatform\WorkstreamPlatform_WebRole\Extensions\PlatformHtmlHelpersExtensions.cs 97 27 WorkstreamPlatform_WebRole So according to the message, the parameter is invalid. But the method is actually declared like this: public static MvcHtmlString ValidationMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression); So actually it should work.

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• Expression Tree with Property Inheritance causes an argument exception

  - by Adam Driscoll

  Following this post: link text I'm trying to create an expression tree that references the property of a property. My code looks like this: public interface IFoo { void X {get;set;} } public interface IBar : IFoo { void Y {get;set;} } public interface IFooBarContainer { IBar Bar {get;set;} } public class Filterer { //Where T = "IFooBarContainer" public IQueryable<T> Filter<T>(IEnumerable<T> collection) { var argument = Expression.Parameter(typeof (T), "item"); //... //where propertyName = "IBar.X"; PropertyOfProperty(argument, propertyName); } private static MemberExpression PropertyOfProperty(Expression expr, string propertyName) { return propertyName.Split('.').Aggregate<string, MemberExpression>(null, (current, property) => Expression.Property(current ?? expr, property)); } } I receive the exception: System.ArgumentException: Instance property 'X' is not defined for type 'IBar' ReSharper turned the code in the link above into the condensed statement in my example. Both forms of the method returned the same error. If I reference IBar.Y the method does not fail.

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• Evaluate an expression tree

  - by Phronima

  Hi, This project that I'm working on requires that an expression tree be constructed from a string of single digit operands and operators both represented as type char. I did the implmentation and the program up to that point works fine. I'm able to print out the inorder, preorder and postorder traversals in the correct way. The last part calls for evaulating the expression tree. The parameters are an expression tree "t" and its root "root". The expression tree is ((3+2)+(6+2)) which is equal to 13. Instead I get 11 as the answer. Clearly I'm missing something here and I've done everything short of bashing my head against the desk. I would greatly appreciate it if someone can point me in the right direction. (Note that at this point I'm only testing addition and will add in the other operators when I get this method working.) public int evalExpression( LinkedBinaryTree t, BTNode root ) { if( t.isInternal( root ) ) { int x = 0, y = 0, value = 0; char operator = root.element(); if( root.getLeft() != null ) x = evalExpression(t, t.left( root ) ); if( root.getRight() != null ) y = evalExpression(t, t.right( root ) ); if( operator == '+' ) { value = value + Character.getNumericValue(x) + Character.getNumericValue(y); } return value; } else { return root.element(); } }

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• How to obtain a random sub-datatable from another data table

  - by developerit

  Introduction In this article, I’ll show how to get a random subset of data from a DataTable. This is useful when you already have queries that are filtered correctly but returns all the rows. Analysis I came across this situation when I wanted to display a random tag cloud. I already had the query to get the keywords ordered by number of clicks and I wanted to created a tag cloud. Tags that are the most popular should have more chance to get picked and should be displayed larger than less popular ones. Implementation In this code snippet, there is everything you need. ' Min size, in pixel for the tag Private Const MIN_FONT_SIZE As Integer = 9 ' Max size, in pixel for the tag Private Const MAX_FONT_SIZE As Integer = 14 ' Basic function that retreives Tags from a DataBase Public Shared Function GetTags() As MediasTagsDataTable ' Simple call to the TableAdapter, to get the Tags ordered by number of clicks Dim dt As MediasTagsDataTable = taMediasTags.GetDataValide ' If the query returned no result, return an empty DataTable If dt Is Nothing OrElse dt.Rows.Count < 1 Then Return New MediasTagsDataTable End If ' Set the font-size of the group of data ' We are dividing our results into sub set, according to their number of clicks ' Example: 10 results -> [0,2] will get font size 9, [3,5] will get font size 10, [6,8] wil get 11, ... ' This is the number of elements in one group Dim groupLenth As Integer = CType(Math.Floor(dt.Rows.Count / (MAX_FONT_SIZE - MIN_FONT_SIZE)), Integer) ' Counter of elements in the same group Dim counter As Integer = 0 ' Counter of groups Dim groupCounter As Integer = 0 ' Loop througt the list For Each row As MediasTagsRow In dt ' Set the font-size in a custom column row.c_FontSize = MIN_FONT_SIZE + groupCounter ' Increment the counter counter += 1 ' If the group counter is less than the counter If groupLenth <= counter Then ' Start a new group counter = 0 groupCounter += 1 End If Next ' Return the new DataTable with font-size Return dt End Function ' Function that generate the random sub set Public Shared Function GetRandomSampleTags(ByVal KeyCount As Integer) As MediasTagsDataTable ' Get the data Dim dt As MediasTagsDataTable = GetTags() ' Create a new DataTable that will contains the random set Dim rep As MediasTagsDataTable = New MediasTagsDataTable ' Count the number of row in the new DataTable Dim count As Integer = 0 ' Random number generator Dim rand As New Random() While count < KeyCount Randomize() ' Pick a random row Dim r As Integer = rand.Next(0, dt.Rows.Count - 1) Dim tmpRow As MediasTagsRow = dt(r) ' Import it into the new DataTable rep.ImportRow(tmpRow) ' Remove it from the old one, to be sure not to pick it again dt.Rows.RemoveAt(r) ' Increment the counter count += 1 End While ' Return the new sub set Return rep End Function Pro’s This method is good because it doesn’t require much work to get it work fast. It is a good concept when you are working with small tables, let says less than 100 records. Con’s If you have more than 100 records, out of memory exception may occur since we are coping and duplicating rows. I would consider using a stored procedure instead.

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• SQL SERVER- IF EXISTS(Select null from table) vs IF EXISTS(Select 1 from table)

  - by pinaldave

  Few days ago I wrote article about SQL SERVER – Stored Procedure Optimization Tips – Best Practices. I received lots of comments on particular blog article. In fact, almost all the comments are very interesting. If you have not read all the comments, I strongly suggest to read them. Click here to read the comments. The [...]

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• Cannot insert explicit value for identity column in table ‘table’ when IDENTITY_INSERT is set to OFF

  - by Derek D.

  This error occurs when trying to insert into a column containing an identity. An Identity column is not able to be inserted into without the use of a special command mentioned below. Identity columns are columns that automatically increment when a value is inserted into a row. They are commonly used [...]

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• Pass table as parameter to SQLCLR TV-UDF

  - by Skeolan

  We have a third-party DLL that can operate on a DataTable of source information and generate some useful values, and we're trying to hook it up through SQLCLR to be callable as a table-valued UDF in SQL Server 2008. Taking the concept here one step further, I would like to program a CLR Table-Valued Function that operates on a table of source data from the DB. I'm pretty sure I understand what needs to happen on the T-SQL side of things; but, what should the method signature look like in the .NET (C#) code? What would be the parameter datatype for "table data from SQL Server?" e.g. /* Setup */ CREATE TYPE InTableType AS TABLE (LocationName VARCHAR(50), Lat FLOAT, Lon FLOAT) GO CREATE TYPE OutTableType AS TABLE (LocationName VARCHAR(50), NeighborName VARCHAR(50), Distance FLOAT) GO CREATE ASSEMBLY myCLRAssembly FROM 'D:\assemblies\myCLR_UDFs.dll' WITH PERMISSION_SET = EXTERNAL_ACCESS GO CREATE FUNCTION GetDistances(@locations InTableType) RETURNS OutTableType AS EXTERNAL NAME myCLRAssembly.GeoDistance.SQLCLRInitMethod GO /* Execution */ DECLARE @myTable InTableType INSERT INTO @myTable(LocationName, Lat, Lon) VALUES('aaa', -50.0, -20.0) INSERT INTO @myTable(LocationName, Lat, Lon) VALUES('bbb', -20.0, -50.0) SELECT * FROM @myTable DECLARE @myResult OutTableType INSERT INTO @myResult MyCLRTVFunction @myTable --returns a table result calculated using the input The lat/lon - distance thing is a silly example that should of course be better handled entirely in SQL; but I hope it illustrates the general intent of table-in - table-out through a table-valued UDF tied to a SQLCLR assembly. I am not certain this is possible; what would the SQLCLRInitMethod method signature look like in the C#? public class GeoDistance { [SqlFunction(FillRowMethodName = "FillRow")] public static IEnumerable SQLCLRInitMethod(<appropriateType> myInputData) { //... } public static void FillRow(...) { //... } } If it's not possible, I know I can use a "context connection=true" SQL connection within the C# code to have the CLR component query for the necessary data given the relevant keys; but that's sensitive to changes in the DB schema. So I hope to just have SQL bundle up all the source data and pass it to the function. Bonus question - assuming this works at all, would it also work with more than one input table?

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• How to fill DataGridView from nested table oracle

  - by arkadiusz85

  I want to create my type: CREATE TYPE t_read AS OBJECT ( id_worker NUMBER(20), how_much NUMBER(5,2), adddate_r DATE, date_from DATE, date_to DATE ); I create a table of my type: CREATE TYPE t_tab_read AS TABLE OF t_read; Next step is create a table with my type: enter code hereCREATE TABLE Reading ( id_watermeter NUMBER(20) constraint Watermeter_fk1 references Watermeters(id_watermeter), read t_tab_read ) NESTED TABLE read STORE AS store_read ; Microsoft Visual Studio can not display this type in DataGridView. I use Oracle.Command: C# using Oracle.DataAccess; using Oracle.DataAccess.Client; private void button1_Click(object sender, EventArgs e) { try { //my working class to connect to database ConnectionClass.BeginConnection(); OracleDataAdapter tmp = new OracleDataAdapter(); tmp = ConnectionClass.ReadCommand(ReadClass.test()); DataSet dataset4 = new DataSet(); tmp.Fill(dataset4, "Read1"); dataGridView4.DataSource = dataset4.Tables["Read1"]; } catch (Exception o) { MessageBox.Show(o.Message); } public class ReadClass { public static OracleCommand test() { string sql = "select c.id_watermeter, a. from reading c , table (c.read) a where id_watermeter=1"; ConnectionClass.Command1= new OracleCommand(sql, ConnectionClass.Connection); ConnectionClass.Command1.CommandType = CommandType.Text; return ConnectionClass.Command1; } } I tray: string sql = "select r.id_watermeter, o.id_worker, o.how_much, o.adddate_r, o.date_from, o.date_to from reading r, table (r.read) o where r.id_watermeter=1" string sql = "select a.from reading c , Table (c.read) a where id_watermeter=1" string sql = "select a.id_worker, a.how_much, a.adddate_r, a.date_from, a.date_to from reading c , table (c.read) a where id_watermeter=1" string sql = "select c.id_watermeter, a. from reading c , table (c.read) a where id_watermeter=1" Error : Unsuported Oracle data type USERDEFINED encountered Sombady can help me how to fill DataGridView using data from nested table. I am using Oracle 10g XE

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• problem in table:

  - by Ayyappan.Anbalagan

  i had table inside the another table, my inner table display the image, if i enter the text after the inner table,The text should display right side of the table and the bottom of the inner table.how do i do this??? "the below code display the outer table text always displayed bellow the inner table" Heading ## <tr style=" width:500px; float:left;"> <td style="border: thin ridge #008000; text-align:left;" align="left"; > <table class="" style=" border: 1px solid #800000; width:200px; float:left; height: 200px;"> <tr> <td>&nbsp;stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow&nbsp; </td> </tr> </table> stackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow stackoverflowstackoverflow statackoverflow sta</td> </tr> </table>

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