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  • Binding Data to DataGridView in VB.Net

    - by Peter
    Hi, I have a bit of code which loads data from a stored procedure in MS SQL Server and then loads the data to a datagridview, which works fine. What i want is for the code that connects / loads the data to sit in my Database Class and then everything associated with the datagridview to be stored in my Form but i am having problems passing the contents of the bindingsource over to the Form from the Database Class. Form1 Public Class Form1 Dim myDatabaseObj As New Class1() Dim bindingSource1 As New BindingSource() Dim connectString As New SqlConnection Dim objDataAdapter As New SqlDataAdapter Dim table As New DataTable() Dim tabletest As New DataTable() Private Sub loadCompanyList() Try Me.dgv_CompanyList.DataSource = Me.bindingSource1 getCompanyList() Catch ex As NullReferenceException End Try End Sub Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load loadCompanyList() End Sub End Class Database Class When i try place the getCompanyList() in a class and then create a new object that references the Form() it does not seem to return any value from the table to the MyForm.BindingSource1.Datasource meaning my datagridview displays not data. ..... Private Sub getCompanyList() Try Dim myForm as new Form() connect_Transaction_Database() objDataAdapter.SelectCommand = New SqlCommand() objDataAdapter.SelectCommand.Connection = connectString objDataAdapter.SelectCommand.CommandText = "sp_GetCompanyList" objDataAdapter.SelectCommand.CommandType = CommandType.StoredProcedure Dim commandBuilder As New SqlCommandBuilder(Me.objDataAdapter) Dim table As New DataTable() table.Locale = System.Globalization.CultureInfo.InvariantCulture Me.objDataAdapter.Fill(table) **MyForm.bindingSource1.DataSource = table** Catch ex As DataException MsgBox(ex.Message) Catch ex As NullReferenceException MsgBox(ex.Message) End Try disconnect_Transaction_Database() End Sub If anyone could help. Thank you. Peter

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  • Create System.Data.Linq.Table in Code for Testing

    - by S. DePouw
    I have an adapter class for Linq-to-Sql: public interface IAdapter : IDisposable { Table<Data.User> Activities { get; } } Data.User is an object defined by Linq-to-Sql pointing to the User table in persistence. The implementation for this is as follows: public class Adapter : IAdapter { private readonly SecretDataContext _context = new SecretDataContext(); public void Dispose() { _context.Dispose(); } public Table<Data.User> Users { get { return _context.Users; } } } This makes mocking the persistence layer easy in unit testing, as I can just return whatever collection of data I want for Users (Rhino.Mocks): Expect.Call(_adapter.Users).Return(users); The problem is that I cannot create the object 'users' since the constructors are not accessible and the class Table is sealed. One option I tried is to just make IAdapter return IEnumerable or IQueryable, but the problem there is that I then do not have access to the methods ITable provides (e.g. InsertOnSubmit()). Is there a way I can create the fake Table in the unit test scenario so that I may be a happy TDD developer?

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  • relational data from xml

    - by Beta033
    Our problem is this, we have a relational database to store objects in tables. As any relational database could, several of these tables have multiple foreign keys pointing to other tables (all pretty normal stuff) We've been trying to identify a solution to allow export of this relational data, ideally, only 1 of the objects in the model, to some sort of file (xml, text, ??). So it wouldn't be simple enough to just export 1 table as data stored in other tables would contribute to the complete model of the object. Something like the following picture: Toward this, i've written a routine to export the structure by following the foreign key paths which exports something similar to the following. <Tables> <TableA PK="1", val1, val2, val3> <TableC PK="1", FK_A="1", Val1, val2, val3> <TableC PK="2", FK_A="1", val1, val2, val3> <TableB PK="1", FK_A="1", FK_C="1", val1, val2, val3> <TableB PK="2", FK_A="1", FK_C="2", val1, val2, val3> <TableD PK="1", FK_B="1", FK_C="1", val1> <TableD PK="2", FK_B="2", FK_C="1", val1> </Tables> However, given this structure, it cannot be placed into a heirarchial format (ie D2 is a child of C1 and B2; and B2 is a child of C2) Which in turn, makes my life very difficult when trying to identify a methodology to reimport (and reKey) these objects. Has anybody done anything like this? how do you do it? are there tools or documentation on how this is best accomplished? Thanks for your help.

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  • Linq to SQL not inserting data onto the DB

    - by Jesus Rodriguez
    Hello! I have a little / weird behaviour here and Im looking over internet and SO and I didn't find a response. I have to admit that this is my first time using databases, I know how to use them with SQL but never used it actually. Anyway, I have a problem with my app inserting data, I just created a very simple project for testing that and no solution yet. I have an example database with Sql Server Id - int (identity primary key) Name - nchar(10) (not null) The table is called "Person", simple as pie. I have this: static void Main(string[] args) { var db = new ExampleDBDataContext {Log = Console.Out}; var jesus = new Person {Name = "Jesus"}; db.Persons.InsertOnSubmit(jesus); db.SubmitChanges(); var query = from person in db.Persons select person; foreach (var p in query) { Console.WriteLine(p.Name); } } As you can see, nothing extrange. It show Jesus in the console. But if you see the table data, there is no data, just empty. I comment the object creation and insertion and the foreach doesn't print a thing (normal, there is no data in the database) The weird thing is that I created a row in the database manually and the Id was 2 and no 1 (Was the linq really playing with the database but it didn't create the row?) There is the log: INSERT INTO [dbo].Person VALUES (@p0) SELECT CONVERT(Int,SCOPE_IDENTITY()) AS [value] -- @p0: Input NChar (Size = 10; Prec = 0; Scale = 0) [Jesus] -- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.30729.4926 SELECT [t0].[Id], [t0].[Name] FROM [dbo].[Person] AS [t0] -- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.30729.4926 I am really confused, All the blogs / books use this kind of snippet to insert an element to a database. Thank you for helping.

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  • NSURL Connection will/won't load data

    - by jkap
    So here's my issue: I followed the NSURLConnection tutorial in the iPhone Developer Documentation almost to the T, and it only kinda works. Here's where it all goes wrong: The object seems to be created correctly and delegates to connectionDidFinishLoading, but with any URL I try to load the response data always ends up only being 0 bytes. I am running in the simulator if that makes any difference. Here's my relevant code: - (void)viewDidLoad { [super viewDidLoad]; self.title = @"WVFS Player"; //create a request NSURLRequest *theRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://wvfs.josh-kaplan.com/nowPlaying.php"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0]; // create a connection NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; if(theConnection) { // create the datum responseData=[[NSMutableData data] retain]; } else { // code this later } } - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response { [responseData setLength:0]; } - (void)connectionDidFinishLoading:(NSURLConnection *)connection { // make it work NSLog(@"Succeeded! Received %d bytes of data:",[responseData length]); // release it [connection release]; [responseData release]; } And here's my log output: [Session started at 2010-03-14 09:01:09 -0400.] 2010-03-14 09:01:14.784 WVFS[19571:207] Succeeded! Received 0 bytes of data: Any ideas? Thanks, Josh

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  • Dashboard for collaborative science / data processing projects

    - by rescdsk
    Hi, Continuous Integration servers like Hudson are a pretty amazing addition to software development. I work in an academic research lab, and I'd love to apply similar principles to scientific data analysis. I want a dashboard-like view of which collections of data are fine, which ones are failing their tests (simple shell scripts, mostly), and so on. A lot like the Chromium dashboard (WARNING: page takes a long time to load). It takes work from at least 4 people, and maybe 10 or 12 hours of computer time, to bring our data (from behavioral studies) from its raw form to its final, easily-analyzed form. I've tried Hudson and buildbot, but neither is really appropriate to our workflow. We just want to run a bunch of tests on maybe fifty independent collections of subject data, and display the results nicely. SO! Does anyone have a recommendation of a way to generate this kind of report easily? Or, can you think of a good way to shoehorn this kind of workflow into a continuous integration server? Or, can you recommend a unit testing dashboard that could deal with tests that are little shell scripts rather than little functions? Thank you!

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  • Storing statistics of multple data types in SQL Server 2008

    - by Mike
    I am creating a statistics module in SQL Server 2008 that allows users to save data in any number of formats (date, int, decimal, percent, etc...). Currently I am using a single table to store these values as type varchar, with an extra field to denote the datatype that it should be. When I display the value, I use that datatype field to format it. I use sprocs to calculate the data for reporting; and the datatype field to convert to the appropriate datatype for the appropriate calculations. This approach works, but I don't like storing all kinds of data in a varchar field. The only alternative that I can see is to have separate tables for each datatype I want to store, and save the record information to the appropriate table based on datatype. To retreive, I run a case statement to join the appropriate table and get the data. This seems to solve. This however, seems like a lot of work for ... what gain? Wondering if I'm missing something here. Is there a better way to do this? Thanks in advance!

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  • What is the best Binary Decision Diagram library for Java?

    - by reprogrammer
    A Binary Decision Diagram (BDD) is a data structure to represent boolean functions. I'd like use this data structure in a Java program. My search for Java based BDD libraries resulted into the following packages. Java Decision Diagram Libraries JavaBDD JDD JBDD bddbddb If you know of any other BDD libraries available for Java programs, please let me know so that I add it to the list above. If you have used any of these libraries, please tell me about your experience with the library. In particular, I'd like you to compare the available libraries along the following dimensions. Quality. Is the library mature and reasonably bug free? Performance. How do you evaluate the performance of the library? Support. Could you easily get support whenever you encountered a problem with the library? Was the library well documented? Ease of use. Was the API well designed? Could you install and use the library quickly and easily? Please mention the version of the library that you are evaluating.

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  • SQL Server 2005 database design - many-to-many relationships with hierarchy

    - by Remnant
    Note I have completely re-written my original post to better explain the issue I am trying to understand. I have tried to generalise the problem as much as possible. Also, my thanks to the original people who responded. Hopefully this post makes things a little clearer. Context In short, I am struggling to understand the best way to design a small scale database to handle (what I perceive to be) multiple many-to-many relationships. Imagine the following scenario for a company organisational structure: Textile Division Marketing Division | | ---------------------- ---------------------- | | | | HR Dept Finance Dept HR Dept Finance Dept | | | | ---------- ---------- ---------- --------- | | | | | | | | Payroll Hiring Audit Tax Payroll Hiring Audit Accounts | | | | | | | | Emps Emps Emps Emps Emps Emps Emps Emps NB: Emps denotes a list of employess that work in that area When I first started with this issue I made four separate tables: Divisions - Textile, Marketing (PK = DivisionID) Departments - HR, Finance (PK = DeptID) Functions - Payroll, Hiring, Audit, Tax, Accounts (PK = FunctionID) Employees - List of all Employees (PK = EmployeeID) The problem as I see it is that there are multiple many-to-many relationships i.e. many departments have many divisions and many functions have many departments. Question Giving the database structure above, suppose I wanted to do the following: Get all employees who work in the Payroll function of the Marketing Division To do this I need to be able to differentiate between the two Payroll departments but I am not sure how this can be done? I understand that I could build a 'Link / Junction' table between Departments and Functions so that I can retrieve which Functions are in which Departments. However, I would still need to differentiate the Division they belong to. Research Effort As you can see I am an abecedarian when it comes to database deisgn. I have spent the last two days resaerching this issue, traversing nested set models, adjacency models, reading that this issue is known not to be NP complete etc. I am sure there is a simple solution?

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  • Oracle rownum in db2 - Java data archiving

    - by HonorGod
    I have a data archiving process in java that moves data between db2 and sybase. FYI - This is not done through any import/export process because there are several conditions on each table that are available on run-time and so this process is developed in java. Right now I have single DatabaseReader and DatabaseWriter defined for each source and destination combination so that data is moved in multiple threads. I guess I wanted to expand this further where I can have Multiple DatabaseReaders and Multiple DatabaseWriters defined for each source and destination combination. So, for example if the source data is about 100 rows and I defined 10 readers and 10 writer, each reader will read 10 rows and give them to the writer. I hope process will give me extreme performance depending on the resources available on the server [CPU, Memory etc]. But I guess the problem is these source tables do not have primary keys and it is extremely difficult to grab rows in multiple sets. Oracle provides rownum concept and i guess the life is much simpler there....but how about db2? How can I achieve this behavior with db2? Is there a way to say fetch first 10 records and then fetch next 10 records and so on? Any suggestions / ideas ? Db2 Version - DB2 v8.1.0.144 Fix Pack Num - 16 Linux

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  • Windows Programming: ID2D1Bitmap Interface - Getting the Bitmap Data

    - by LostInBrackets
    I've been writing my own library of functions to access some of the new Direct2D Windows libraries. In particular, I've been working on the ID2D1Bitmap interface. I wanted to write a function to return a pointer to the start of the bitmap data (for the editing of particular pixels, or custom encoding or whatever else I might wish for in the future). Unfortunately... problem ahead... I can't seem to find a way to get access to the raw pixel data from the ID2D1Bitmap Interface. Does anyone have an idea how to access this? One of my friends suggested drawing the bitmap to a surface and extracting the bitmap data from there. I don't know if this would work. It definitely seems inefficient and I wouldn't know which kind of surface to use. Any help is appreciated. (c++ in particular, but I assume the code won't be tooo different between languages) (I know I could just read in the data direct from the file, but I'm using the WIC decoders which means it could be in any number of indecipherable formats)

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  • iPhone POST to PHP failing

    - by Alexander
    I have this code here: NSString *post = [NSString stringWithFormat:@"deviceIdentifier=%@&deviceToken=%@",deviceIdentifier,deviceToken]; NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:NO]; NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]]; NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease]; [request setURL:[NSURL URLWithString:@"http://website.com/RegisterScript.php"]]; [request setHTTPMethod:@"POST"]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; [request setValue:@"MyApp-V1.0" forHTTPHeaderField:@"User-Agent"]; [request setHTTPBody:postData]; NSData *urlData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; NSString *response = [[NSString alloc] initWithData:urlData encoding:NSASCIIStringEncoding]; which should be sending data to my PHP server to register the device into our database, but for some of my users no POST data is being sent. I've been told that this line: NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:NO]; may be causing the problem. Any thoughts on why this script would sometimes not send the POST data? On the server I got the packet trace for a failed send and the Content-lenght came up as 0 so no data was sent at all. Thanks for any help

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  • SQLite assembly not copied to output folder for unit testing

    - by Groo
    Problem: SQLite assembly referenced in my DAL assembly does not get copied to the output folder when doing unit tests (Copy local is set to true). I am working on a .Net 3.5 app in VS2008, with NHibernate & SQLite in my DAL. Data access is exposed through the IRepository interface (repository factory) to other layers, so there is no need to reference NHibernate or the System.Data.SQLite assemblies in other layers. For unit testing, there is a public factory method (also in my DAL) which creates an in-memory SQLite session and creates a new IRepository implementation. This is also done to avoid have a shared SQLite in-memory config for all assemblies which need it, and to avoid referencing those DAL internal assemblies. The problem is when I run unit tests which reside a separate project - if I don't add System.Data.SQLite as a reference to the unit test project, it doesn't get copied to the TestResults...\Out folder (although this project references my DAL project, which references System.Data.SQLite, which has its Copy local property set to true), so the tests fail while NHibernate is being configured. If I add the reference to my testing project, then it does get copied and unit tests work. What am I doing wrong?

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  • When should I be cautious using about data binding in .NET?

    - by Ben McCormack
    I just started working on a small team of .NET programmers about a month ago and recently got in a discussion with our team lead regarding why we don't use databinding at all in our code. Every time we work with a data grid, we iterate through a data table and populate the grid row by row; the code usually looks something like this: Dim dt as DataTable = FuncLib.GetData("spGetTheData ...") Dim i As Integer For i = 0 To dt.Rows.Length - 1 '(not sure why we do not use a for each here)' gridRow = grid.Rows.Add() gridRow(constantProductID).Value = dt("ProductID").Value gridRow(constantProductDesc).Value = dt("ProductDescription").Value Next '(I am probably missing something in the code, but that is basically it)' Our team lead was saying that he got burned using data binding when working with Sheridan Grid controls, VB6, and ADO recordsets back in the nineties. He's not sure what the exact problem was, but he remembers that binding didn't work as expected and caused him some major problems. Since then, they haven't trusted data binding and load the data for all their controls by hand. The reason the conversation even came up was because I found data binding to be very simple and really liked separating the data presentation (in this case, the data grid) from the in-memory data source (in this case, the data table). "Loading" the data row by row into the grid seemed to break this distinction. I also observed that with the advent of XAML in WPF and Silverlight, data-binding seems like a must-have in order to be able to cleanly wire up a designer's XAML code with your data. When should I be cautious of using data-binding in .NET?

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  • CURL & web.py: transfer closed with outstanding read data remaining

    - by Richard J
    Hi Folks, I have written a web.py POST handler, thus: import web urls = ('/my', 'Test') class Test: def POST(self): return "Here is your content" app = web.application(urls, globals()) if __name__ == "__main__": app.run() When I interact with it using Curl from the command line I get different responses depending on whether I post it any data or not: curl -i -X POST http://localhost:8080/my HTTP/1.1 200 OK Transfer-Encoding: chunked Date: Thu, 06 Jan 2011 16:42:41 GMT Server: CherryPy/3.1.2 WSGI Server Here is your content (Posting of no data to the server gives me back the "Here is your content" string) curl -i -X POST --data-binary "@example.zip" http://localhost:8080/my HTTP/1.1 100 Content-Length: 0 Content-Type: text/plain HTTP/1.1 200 OK Transfer-Encoding: chunked Date: Thu, 06 Jan 2011 16:43:47 GMT Server: CherryPy/3.1.2 WSGI Server curl: (18) transfer closed with outstanding read data remaining (Posting example.zip to the server results in this error) I've scoured the web.py documentation (what there is of it), and can't find any hints as to what might be going on here. Possibly something to do with 100 continue? I tried writing a python client which might help clarify: h1 = httplib.HTTPConnection('localhost:8080') h1.request("POST", "http://localhost:8080/my", body, headers) print h1.getresponse() body = the contents of the example.zip, and headers = empty dictionary. This request eventually timed out without printing anything, which I think exonerates curl from being the issue, so I believe something is going on in web.py which isn't quite right (or at least not sufficiently clear) Any web.py experts got some tips? Cheers, Richard

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  • Magento resource model for table with compound primary key

    - by sdek
    I am creating a custom module for a Magento ecommerce site, and the module will center around a new (ie, custom) table that has a compound/composite primary key, or rather the table has two columns that make up the primary key. Does anybody know how to create your models/resource models based on a table with a compound key? To give a few more details, I have looked up several tutorials and also used the excellent moduleCreator script. But it seems like all the tutorials revolve around the table having a PK with just one column in it. Something like this: class <Namespace>_<Module>_Model_Mysql4_<Module> extends Mage_Core_Model_Mysql4_Abstract { public function _construct(){ $this->_init('<module_alias>/<table_alias>', '<table_primary_key_id>'); } } Also, I just noticed that looking at the database model almost all tables have a single primary key. I understand this has much to do with the EAV-style db structure, but still is it possible to use a table with a compound PK? I want to stick with the Magento framework/conventions if possible. Is it discouraged? Should I just change the structure of my custom table to have some dummy id column? I do have the ability to do that, but geez! (Another side note that I thought I would mention is that it looks like the Zend Framework provides a way to base a class on a table with compound primary key (see Example #20 on this page - about half-way down), so it seems that the Magento framework should also provide for it... I just don't see how.)

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  • Strange error when filling a data adapter.

    - by Tim C
    I am receiving the following error in my code (c#, .Net 3.5, VS2008) when I try to connect to an Excel sheet and fill a OleDbDataAdapter with the results of a query. First the error: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. And here is the code, which is honestly pretty simple: var excelFileName = string.Format("c:/Metadata_Tool.xlsm"); var connectionString = string.Format("Provider=Microsoft.ACE.OLEDB.12.0; Data Source={0}; Extended Properties=Excel 12.0;HDR=YES;", excelFileName); var adapter = new OleDbDataAdapter("Select * FROM [Video Tagging XML]", connectionString); var ds = new DataSet(); adapter.Fill(ds, "VTX"); DataTable data = ds.Tables["VTX"]; foreach (DataRow myRow in data.Rows) { foreach (DataColumn myColumn in data.Columns) { Console.Write("\t{0}", myRow[myColumn]); } Console.WriteLine(); } Console.ReadLine(); I get the error on the line adapter.Fill(ds,"VTX");. I did find a microsoft forum post saying to turn on JIT optimization in VS2008 from the Tools/Options/Debug/General menu, but this did not seem to help. Any help would be greatly appreciated thanks!

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  • Strip parity bits in C from 8 bits of data followed by 1 parity bit

    - by dubnde
    I have a buffer of bits with 8 bits of data followed by 1 parity bit. This pattern repeats itself. The buffer is currently stored as an array of octets. Example (p are parity bits): 0001 0001 p000 0100 0p00 0001 00p01 1100 ... should become 0001 0001 0000 1000 0000 0100 0111 00 ... Basically, I need to strip of every ninth bit to just obtain the data bits. How can I achieve this? This is related to another question asked here sometime back. This is on a 32 bit machine so the solution to the related question may not be applicable. The maximum possible number of bits is 45 i.e. 5 data octets This is what I have tried so far. I have created a "boolean" array and added the bits into the array based on the the bitset of the octet. I then look at every ninth index of the array and through it away. Then move the remaining array down one index. Then I've got only the data bits left. I was thinking there may be better ways of doing this.

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  • CLR Stored Procedures

    - by Paul Hatcherian
    In an ASP.NET application, I have a small number of fairly complex, frequently used operations to execute against a database. In these operations, one or more of several tables needs updates or inserts based a logical evaluation of both input parameters and values of certain tables. I've maintained a separation of logic and data access, so the operation currently looks like this: Request received from client Business layer invokes data layer to retrieve data from database Business layer processes result and determines which operation to execute Business layer invokes appropriate data operation Response sent to client As you can see, the client is kept waiting while two separate requests are made to the database. In searching for a solution to this, I've found CLR Stored Procedures, but I'm not sure if I have the right idea about what they are useful for. I have written a replacement for the code above which especially places steps 2-4 in a CLR SP. My understanding is that the SP will be executed locally by SQL Server and result in only one call being made to the server. My initial benchmark tests show this is actually orders of magnitude slower than my original code, but I attribute that recompilation of the code I have not worked out yet and/or some flaw in my environment. My question is basically, is this the intended use of CLR SPs or am I missing something? I realize this is a bit of a compromise structurally, so if there's a better way to do it I'd love to hear it.

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  • Getting data from array of DataSet objects returned from web service

    - by Sarah Vessels
    I have a web service that I want to access when it is added as a web reference to my C# project. A particular method in the web service takes a SQL query string and returns the results of the query as a custom type. When I add the web service reference, the method shows up as returning DataSet[] instead of the custom type. This is fine provided I can still somehow access the data returned from the query within those DataSet objects. I ran a particular query that should return 6 rows; I got back a DataSet[] array with 6 elements. However, when I iterate over those DataSet objects, none of them has any tables (via the Tables property on the DataSet). What gives? Where is my data? The web service is tested and works when I use it as a data source in a Report Builder 2.0 report. I am able to send an XML SOAP query to the web service and get back XML results containing my data.

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  • Should I move big data blobs in JSON or in separate binary connection?

    - by Amagrammer
    QUESTION: Is it better to send large data blobs in JSON for simplicity, or send them as binary data over a separate connection? If the former, can you offer tips on how to optimize the JSON to minimize size? If the latter, is it worth it to logically connect the JSON data to the binary data using an identifier that appears in both, e.g., as "data" : "< unique identifier " in the JSON and with the first bytes of the data blob being < unique identifier ? CONTEXT: My iPhone application needs to receive JSON data over the 3G network. This means that I need to think seriously about efficiency of data transfer, as well as the load on the CPU. Most of the data transfers will be relatively small packets of text data for which JSON is a natural format and for which there is no point in worrying much about efficiency. However, some of the most critical transfers will be big blobs of binary data -- definitely at least 100 kilobytes of data, and possibly closer to 1 megabyte as customers accumulate a longer history with the product. (Note: I will be caching what I can on the iPhone itself, but the data still has to be transferred at least once.) It is NOT streaming data. I will probably use a third-party JSON SDK -- the one I am using during development is here. Thanks

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  • rs232 communication, general timing question

    - by Sunny Dee
    Hi, I have a piece of hardware which sends out a byte of data representing a voltage signal at a frequency of 100Hz over the serial port. I want to write a program that will read in the data so I can plot it. I know I need to open the serial port and open an inputstream. But this next part is confusing me and I'm having trouble understanding the process conceptually: I create a while loop that reads in the data from the inputstream 1 byte at a time. How do I get the while loop timing so that there is always a byte available to be read whenever it reaches the readbyte line? I'm guessing that I can't just put a sleep function inside the while loop to try and match it to the hardware sample rate. Is it just a matter of continuing reading the inputstream in the while loop, and if it's too fast then it won't do anything (since there's no new data), and if it's too slow then it will accumulate in the inputstream buffer? Like I said, i'm only trying to understand this conceptually so any guidance would be much appreciated! I'm guessing the idea is independent of which programming language I'm using, but if not, assume it is for use in Java. Thanks!

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  • Sweave/R - Automatically generating an appendix that contains all the model summaries/plots/data pro

    - by John Horton
    I like the idea of making research available at multiple levels of detail i.e., abstract for the casually curious, full text for the more interested, and finally the data and code for those working in the same area/trying to reproduce your results. In between the actual text and the data/code level, I'd like to insert another layer. Namely, I'd like to create a kind of automatically generated appendix that contains the full regression output, diagnostic plots, exploratory graphs data profiles etc. from the analysis, regardless of whether those plots/regressions etc. made it into the final paper. One idea I had was to write a script that would examine the .Rnw file and automatically: Profile all data sets that are loaded (sort of like the Hmisc(?) package) Summarize all regressions - i.e., run summary(model) for all models Present all plots (regardless of whether they made it in the final version) The idea is to make this kind of a low-effort, push-button sort of thing as opposed to a formal appendix written like the rest of a paper. What I'm looking for is some ideas on how to do this in R in a relatively simple way. My hunch is that there is some way of going through the namespace, figuring out what something is and then dumping into a PDF. Thoughts? Does something like this already exist?

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  • Automation Error when exporting Excel data to SQL Server

    - by brohjoe
    I'm getting an Automation error upon running VBA code in Excel 2007. I'm attempting to connect to a remote SQL Server DB and load data to from Excel to SQL Server. The error I get is, "Run-time error '-2147217843(80040e4d)': Automation error". I checked out the MSDN site and it suggested that this may be due to a bug associated with the sqloledb provider and one way to mitigate this is to use ODBC. Well I changed the connection string to reflect ODBC provider and associated parameters and I'm still getting the same error. Here is the code with ODBC as the provider: Dim cnt As ADODB.Connection Dim rst As ADODB.Recordset Dim stSQL As String Dim wbBook As Workbook Dim wsSheet As Worksheet Dim rnStart As Range Public Sub loadData() 'This was set up using Microsoft ActiveX Data Components version 6.0. 'Create ADODB connection object, open connection and construct the connection string object. Set cnt = New ADODB.Connection cnt.ConnectionString = "Driver={SQL Server}; Server=onlineSQLServer2010.foo.com; Database=fooDB;Uid=logonalready;Pwd='helpmeOB1';" cnt.Open On Error GoTo ErrorHandler 'Open Excel and run query to export data to SQL Server. strSQL = "SELECT * INTO SalesOrders FROM OPENDATASOURCE('Microsoft.ACE.OLEDB.12.0'," & _ "'Data Source=C:\Database.xlsx; Extended Properties=Excel 12.0')...[SalesOrders$]" cnt.Execute (strSQL) 'Error handling. ErrorExit: 'Reclaim memory from the connection objects Set rst = Nothing Set cnt = Nothing Exit Sub ErrorHandler: MsgBox Err.Description, vbCritical Resume ErrorExit 'clean up and reclaim memory resources. If CBool(cnt.State And adStateOpen) Then Set rst = Nothing Set cnt = Nothing cnt.Close End If End Sub

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  • Map element position in data file to class property

    - by Augusto
    I need to read/write files, following a format provided by a third party specification. The specification itself is pretty simple: it says the position and the size of the data that will be saved in the file. For example: Position Size Description -------------------------------------------------- 0001 10 Device serial number 0011 02 Hour 0013 02 Minute 0015 02 Second 0017 02 Day 0019 02 Month 0021 02 Year The list is very long, it has about 400 elements. But lots of them can be combined. For example, hour, minute, second, day, month and year can be combined in a single DateTime object. I've splitted the elements into about 4 categories, and created separeted classes for holding the data. So, instead of a big structure representing the data, I have some smaller classes. I've also created different classes for reading and writing the data. The problem is: how to map the positions in the file to the objects properties, so that I don't need to repeat the values in the reading/writing class? I could use some custom attributes and retrieve them via reflection. But since the code will be running on devices with small memory and processor, it would be nice to find another way. My current read code looks like this: public void Read() { DataFile dataFile = new DataFile(); // the arguments are: position, size dataFile.SerialNumber = ReadLong(1, 10); //... } Any ideas on this one? Thanks!

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