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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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• 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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• How to access this data in PHP?

  - by George Edison

  Okay. Now I give up. I have been playing with this for hours. I have a variable name $data. The variable contains these contents: array ( 'headers' => array ( 'content-type' => 'multipart/alternative; boundary="_689e1a7d-7a0a-442a-bd6c-a1fb1dc2993e_"', ), 'ctype_parameters' => array ( 'boundary' => '_689e1a7d-7a0a-442a-bd6c-a1fb1dc2993e_', ), 'parts' => array ( 0 => stdClass::__set_state(array( 'headers' => array ( 'content-type' => 'text/plain; charset="iso-8859-1"', 'content-transfer-encoding' => 'quoted-printable', ), 'ctype_primary' => 'text', )), ), ) I removed some non-essential data. I want to access the headers value (on the second line above) - simple: $data->headers I want to access the headers value (on the fourteenth line after the stdClass:: stuff) - how? How can I possibly access the values within the stdClass::__set_state section? I tried var_export($data->parts); but all I get is NULL

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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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• 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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• Struggling with a data modeling problem

  - by rpat

  I am struggling with a data model (I use MySQL for the database). I am uneasy about what I have come up with. If someone could suggest a better approach, or point me to some reference matter I would appreciate it. The data would have organizations of many types. I am trying to do a 3 level classification (Class, Category, Type). Say if I have 'Italian Restaurant', it will have the following classification Food Services Restaurants Italian However, an organization may belong to multiple groups. A restaurant may also serve Chinese and Italian. So it will fit into 2 classifications Food Services Restaurants Italian Food Services Restaurants Chinese The classification reference tables would be like the following: ORG_CLASS (RowId, ClassCode, ClassName) 1, FOOD, Food Services ORG_CATEGORY(RowId, ClassCode, CategoryCode, CategoryName) 1, FOOD, REST, Restaurants ORG_TYPE (RowId, ClassCode, CategoryCode, TypeCode, TypeName) 100, FOOD, REST, ITAL, Italian 101, FOOD, REST, CHIN, Chinese 102, FOOD, REST, SPAN, Spanish 103, FOOD, REST, MEXI, Mexican 104, FOOD, REST, FREN, French 105, FOOD, REST, MIDL, Middle Eastern The actual data tables would be like the following: I will allow an organization a max of 3 classifications. I will have 3 GroupIds each pointing to a row in ORG_TYPE. So I have my ORGANIZATION_TABLE ORGANIZATION_TABLE (OrgGroupId1, OrgGroupId2, OrgGroupId3, OrgName, OrgAddres) 100,103,NULL,MyRestaurant1, MyAddr1 100,102,NULL,MyRestaurant2, MyAddr2 100,104,105, MyRestaurant3, MyAddr3 During data add, a dialog could let the user choose the clssa, category, type and the corresponding GroupId could be populated with the rowid from the ORG_TYPE table. During Search, If all three classification are chosen, It will be more specific. For example, if Food Services Restaurants Italian is the criteria, the where clause would be 'where OrgGroupId1 = 100' If only 2 levels are chosen Food Services Restaurants I have to do 'where OrgGroupId1 in (100,101,102,103,104,105, .....)' - There could be a hundred in that list I will disallow class level search. That is I will force selection of a class and category The Ids would be integers. I am trying to see performance issues and other issues. Overall, would this work? or I need to throw this out and start from scratch.

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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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• 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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• al32utf8 in oracle and SQL Server and DB2 pulling data

  - by Bob

  I have a non-utf8 oracle database running on 11.1.0.7. We need to support greek characters. So we have two options: use nvarchar, nclob fields for those fields that need greek (it is not all fields). We have tested this and gotten it to work with java coding. convert Oracle to AL32UTF8 database. I am not asking how to do this. I got this from the Oracle Site/Oracle Support. I know what is involved, lossy data, etc, increasing the size of the database. My question is we have users to our system that connect to our database with database links but work on SQL Server and IBM DB2 databases. I do not have access to those databases and I do not have experience with them. If they are not in UTF-8 databases what happens when they pull UTF8 data? I would assume that English/Ascii characters are fine and the greek will end up as junk data. I also ran Oracle Character set scanner (oracle command line utility you use to get info about the affects of a character set conversion). It says that my database will crease in sizez by about 20%. Does this have an affect on users with 3rd party databases? These are customers of our data and there is a limit to how much access I can have to them to run tests. Any information you have would be welcome.

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• Aggregating, restructuring hourly time series data in R

  - by Advait Godbole

  I have a year's worth of hourly data in a data frame in R: > str(df.MHwind_load) # compactly displays structure of data frame 'data.frame': 8760 obs. of 6 variables: $ Date : Factor w/ 365 levels "2010-04-01","2010-04-02",..: 1 1 1 1 1 1 1 1 1 1 ... $ Time..HRs. : int 1 2 3 4 5 6 7 8 9 10 ... $ Hour.of.Year : int 1 2 3 4 5 6 7 8 9 10 ... $ Wind.MW : int 375 492 483 476 486 512 421 396 456 453 ... $ MSEDCL.Demand: int 13293 13140 12806 12891 13113 13802 14186 14104 14117 14462 ... $ Net.Load : int 12918 12648 12323 12415 12627 13290 13765 13708 13661 14009 ... While preserving the hourly structure, I would like to know how to extract a particular month/group of months the first day/first week etc of each month all mondays, all tuesdays etc of the year I have tried using "cut" without result and after looking online think that "lubridate" might be able to do so but haven't found suitable examples. I'd greatly appreciate help on this issue.

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• Scripts to parse and download iTunes Connect and AppStore data

  - by bradhouse

  I'm looking for recommendations of a script or series of scripts that download and parse iTunes Connect sales data and AppStore comments, ratings and rankings data for a defined app. I'm also aware of solutions like: AppViz appsales-mobile iphone-stats Heartbeat.app I'm sure I'll find a few more with more searching. I can't help but feel there must be a really decent set of open source scripts out there to do this, given how many developers are now writing apps for the AppStore. Would be interested to hear any commercial offerings as well (although my personal preference is for open source, so I can at least see what it is doing with my iTunes Connect login credentials). To be clear, I'm really looking for something that hits all of the areas mentioned: App Store (per store) Comments Ratings Category/store rankings iTunes Connect The contents of the sales reports Analysis/graphs of the data is not necessary (but would be a nice to have I guess). I'm not really looking for something like AppSales Mobile above, I would like the raw data so I can do my own analysis and formatting. So far it looks like AppViz (listed above) is the best out there. Any suggestions on what is good/available or should I just go roll my own?

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• WPF tree data binding

  - by Am

  Hi, I have a well defined tree repository. Where I can rename items, move them up, down, etc. Add new and delete. The data is stored in a table as follows: Index Parent Label Left Right 1 0 root 1 14 2 1 food 2 7 3 2 cake 3 4 4 2 pie 5 6 5 1 flowers 8 13 6 5 roses 9 10 7 5 violets 11 12 Representing the following tree: (1) root (14) (2) food (7) (8) flowers (13) (3) cake (4) (5) pie (6) (9) roeses (10) (11) violets (12) or root food cake pie flowers roses violets Now, my problem is how to represent this in a bindable way, so that a TreeView can handle all the possible data changes? Renaming is easy, all I need is to make the label an updatble field. But what if a user moves flowers above food? I can make the relevant data changes, but they cause a complete data change to all other items in the tree. And all the examples I found of bindable hierarchies are good for non static trees.. So my current (and bad) solution is to reload the displayed tree after relocation change. Any direction will be good. Thanks

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• SQL Server Multi-statement UDF - way to store data temporarily required

  - by Kharlos Dominguez

  Hello, I have a relatively complex query, with several self joins, which works on a rather large table. For that query to perform faster, I thus need to only work with a subset of the data. Said subset of data can range between 12 000 and 120 000 rows depending on the parameters passed. More details can be found here: http://stackoverflow.com/questions/3054843/sql-server-cte-referred-in-self-joins-slow As you can see, I was using a CTE to return the data subset before, which caused some performance problems as SQL Server was re-running the Select statement in the CTE for every join instead of simply being run once and reusing its data set. The alternative, using temporary tables worked much faster (while testing the query in a separate window outside the UDF body). However, when I tried to implement this in a multi-statement UDF, I was harshly reminded by SQL Server that multi-statement UDFs do not support temporary tables for some reason... UDFs do allow table variables however, so I tried that, but the performance is absolutely horrible as it takes 1m40 for my query to complete whereas the the CTE version only took 40minutes. I believe the table variables is slow for reasons listed in this thread: http://stackoverflow.com/questions/1643687/table-variable-poor-performance-on-insert-in-sql-server-stored-procedure Temporary table version takes around 1 seconds, but I can't make it into a function due to the SQL Server restrictions, and I have to return a table back to the caller. Considering that CTE and table variables are both too slow, and that temporary tables are rejected in UDFs, What are my options in order for my UDF to perform quickly? Thanks a lot in advance.

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• Sending jQuery.ajax data simultaneous to a form submit

  - by dscher

  I have a bit of a conundrum. I have a form which has numerous fields. There is one field for links where you enter a link, click an add button, and the link(using jQuery) gets added to a link_array. I want this array to be sent via the jQuery.ajax method when the form is submitted. If I send the link_array using $.ajax like this: $.ajax({ type: "POST", url: "add_stock", dataType: "json", data: { "links": link_array } }); when the add link button is selected the data goes no problem to the correct place and gets put in the db correctly. If I bind the above function to the submit form button using $(#stock_form).submit(..... then the rest of the form data is sent but not the link_array. I can obviously pass the link array back into a hidden field in HTML but then I'd have to unpack the array into comma separate values and break the comma-separated string apart in PHP. It just seems 100X easier to unpack the Javascript array in PHP without an other fuss. So, how is it that you can send an array from javascript using $.ajax concurrent to the rest of the $_POST data in HTML? Please note that I'm using Kohana 3.0 framework but really that shouldn't make a difference, what I want to do is add this js array to the $_POST array that is already going. Thanks!

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• How to share data between SSRS Security and Data Processing extension?

  - by user2904681

  I've spent a lot of time trying to solve the issue pointed in title and have no found a solution yet. I use MS SSRS 2012 with custom Security (based on Form Authentication and ClaimsPrincipal) and Data Processing extensions. In Data extension level I need to apply filter programmatically based on one of the claim which I have access in Security extension level only. Here is the problem: I do know how to pass the claim from Security to Data Processing extension code... What I've tried: IAuthenticationExtension.LogonUser(string userName, string password, string authority) { ... ClaimsPrincipal claimsPrincipal = CreateClaimsPrincipal(...); Thread.CurrentPrincipal = claimsPrincipal; HttpContext.Current.User = claimsPrincipal; ... }; But it doesn't work. It seems SSRS overrides it within either GenericPrincipal or FormsIdentity internally. The possible workaround I'm thinking about (but haven't checked it yet): 1. Create HttpModule which will create HttpContext with all required information (minus: will be invoke getting claims each time - huge operation) 2. Write to custom SQL table to store logged users information which is required for Data extension and then read it 3. try somehow to append to cookies due to LogOn and then read each time on IAuthenticationExtension.GetUserInfo and fill HttpContext None of them seems to be a good solution. I would be grateful for any help/advise/comments.

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• modifying ajax returned data before showing

  - by Nick

  I'm processing subscribtion form with jQuery/ajax and need to display results with success function (they are different depending on if email exists in database). But the trick is I do not need h2 and first "p" tag. How can I show only div#alertmsg and second "p" tag? I've tried revoming unnecessary elements with method described here, but it didn't work. Thanks in advance. Here is my code: var dataString = $('#subscribe').serialize(); $.ajax({ type: "POST", url: "/templates/willrock/pommo/user/process.php", data: dataString, success: function(data){ var result = $(data); $('#success').append(result); } Here is the data returned: <h2>Subscription Review</h2> <p><a href="url" onClick="history.back(); return false;"><img src="/templates/willrock/pommo/themes/shared/images/icons/back.png" alt="back icon" class="navimage" /> Back to Subscription Form</a></p> <div id="alertmsg" class="error"> <ul> <li>Email address already exists. Duplicates are not allowed.</li> </ul> </div> <p><a href="login.php">Update your records</a></p>

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• POSTing JSON data to WCF REST

  - by Randall Sexton

  I'm trying to send data from a client application using jQuery to a REST WCF service based on the WCF REST starter kit. Here's what I have so far. Service Definition: [WebHelp(Comment = "Save PropertyValues to the database")] [WebInvoke(Method = "POST", UriTemplate = "PropertyValues_Save", BodyStyle = WebMessageBodyStyle.WrappedRequest, RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)] [OperationContract] public bool PropertyValues_Save(Guid assetId, Dictionary<Guid, string> newValues) { ... } Call from the client: $.ajax({ url:SVC_PROPERTYVALUES_SAVE, type: "POST", contentType: "application/json; charset=utf-8", data: jsonData, dataType: "json", error: function(XMLHttpRequest, textStatus, errorThrown) { alert(textStatus + ' ' + errorThrown); }, success: function(data) { if (data) { alert('Values saved'); $("#confirmSubmit").dialog('close'); } else { alert('Values failed to save'); $("#confirmSubmit").dialog('close'); } } }); Example of the JSON being passed: { "assetId": "d70714c3-e403-4cc5-b8a9-9713d05b2ee0", "newValues": [ { "key": "bd01aa88-b48d-47c7-8d3f-eadf47a46680", "value": "0e9fdf34-2d12-4639-8d70-19b88e753ab1" }, { "key": "06e8eda2-a004-450e-90ab-64df357013cf", "value": "1d490aec-f40e-47d5-865c-07fe9624f955" } ] } I'm using Windows Authentication on the virtual directory. When I call operations that are GETs, everything is fine. This code is prompting the browser to log in. When I enter my credentials, I simply get an alert in my browser which says "error undefined". Even if you can't help my specific error, do you see anything that looks wrong from glancing? I've been beating my head on this nearly all day. Thanks in advance.

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• Collecting high-volume video viewing data

  - by DanK

  I want to add tracking to our Flash-based media player so that we can provide analytics that show what sections of videos are being watched (at the moment, we just register a view when a video starts playing) For example, if a viewer watches the first 30 seconds of a video and then clicks away to something else, we want the data to reflect that. Likewise, if someone watches the first 10 seconds, then scrubs the timeline to the last minute of the video and watches that, we want to register viewing on the parts watched and not the middle section. My first thought was to collect up the viewing data in the player and send it all to the server at the end of a viewing session. Unfortunately, Flash does not seem to have an event that you can hook into when a viewer clicks away from the page the movie is on (probably a good thing - it would be open to abuse) So, it looks like we're going to have to make regular requests to the server as the video is playing. This is obviously going to lead to a high volume of requests when there are large numbers of simultaneous viewers. The simple approach of dumping all these 'heartbeat' events from clients to a database feels like it will quickly become unmanageable so I'm wondering whether I should be taking an approach where viewing sessions are cached in memory and flushed to database when they become inactive (based on a timeout). That way, the data could be stored as time spans rather than individual heartbeats. So, to the question - what is the best way to approach dealing with this kind of high-volume viewing data? Are there any good existing architectures/patterns? Thanks, Dan.

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• In what order does DOJO handles ajax requests?

  - by mm2887

  Hi, Using a form in a dialog box I am using Dojo in jsp to save the form in my database. After that request is completed using dojo.xhrPost() I am sending in another request to update a dropdown box that should include the added form object that was just saved, but for some reason the request to update the dropdown is executed before saving the form in the database even though the form save is called first. Using Firebug I can see that the getLocations() request is completed before the sendForm() request. This is the code: Add Team sendForm("ajaxResult1", "addTeamForm"); dijit.byId("addTeamDialog").hide(); getLocations("locationsTeam"); </script> function sendForm(target, form){ var targetNode = dojo.byId(target); var xhrArgs = { form: form, url: "ajax", handleAs: "text", load: function(data) { targetNode.innerHTML = data; }, error: function(error) { targetNode.innerHTML = "An unexpected error occurred: " + error; } } //Call the asynchronous xhrGet var deferred = dojo.xhrPost(xhrArgs); } function getLocations(id) { var targetNode = dojo.byId(id); var xhrArgs = { url: "ajax", handleAs: "text", content: { location: "yes" }, load: function(data) { targetNode.innerHTML = data; }, error: function(error) { targetNode.innerHTML = "An unexpected error occurred: " + error; } } //Call the asynchronous xhrGet var deferred = dojo.xhrGet(xhrArgs); } Why is this happening? Is there way to make the first request complete first before the second executes? To reduce the possibilities of why this is happening I tried setting the cache property in xhrGet to false but the result is still the same. Please help!

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• Why put a DAO layer over a persistence layer (like JDO or Hibernate)

  - by Todd Owen

  Data Access Objects (DAOs) are a common design pattern, and recommended by Sun. But the earliest examples of Java DAOs interacted directly with relational databases -- they were, in essence, doing object-relational mapping (ORM). Nowadays, I see DAOs on top of mature ORM frameworks like JDO and Hibernate, and I wonder if that is really a good idea. I am developing a web service using JDO as the persistence layer, and am considering whether or not to introduce DAOs. I foresee a problem when dealing with a particular class which contains a map of other objects: public class Book { // Book description in various languages, indexed by ISO language codes private Map<String,BookDescription> descriptions; } JDO is clever enough to map this to a foreign key constraint between the "BOOKS" and "BOOKDESCRIPTIONS" tables. It transparently loads the BookDescription objects (using lazy loading, I believe), and persists them when the Book object is persisted. If I was to introduce a "data access layer" and write a class like BookDao, and encapsulate all the JDO code within this, then wouldn't this JDO's transparent loading of the child objects be circumventing the data access layer? For consistency, shouldn't all the BookDescription objects be loaded and persisted via some BookDescriptionDao object (or BookDao.loadDescription method)? Yet refactoring in that way would make manipulating the model needlessly complicated. So my question is, what's wrong with calling JDO (or Hibernate, or whatever ORM you fancy) directly in the business layer? Its syntax is already quite concise, and it is datastore-agnostic. What is the advantage, if any, of encapsulating it in Data Access Objects?

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• Non distinct Unique ID in MySQL database table.

  - by Geoff

  First of, a simplified version: I am wondering if I can create a trigger to activate during INSERT (it's actually LOAD DATA INFILE) and NOT enter records for an RMA already in my table? I have a table that has no records that are unique. Some may be duplicates but there is one field that I can use to know if the data has been entered or not. For instance RMA Op Days --------------------- 213 Repair 0.10 213 Test 0.20 213 Repair 0.10 So I could do an index on the three columns together but as you see it's possible for an RMA to be in a step for the same amount of time twice so it's possible to have duplicate records. This data comes from a report that I cannot edit and this is all it provides. The key is that an RMA's data is only in the report once so if my database already has that RMA in it's records I want to skip the loading of that RMA's records from the report. By all means please let me know if that didn't make sense, I'll Explain as needed. I'm sure it's not uncommon but I couldn't find anything on the net.

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• Trying to return data asynchronously using jQuery AND jSon in MVC 2.0

  - by Calibre2010

  Hi, I am trying to use Jquerys getJSON method to return data server side to my browser, what happens is the url the getJSON method points to does get reached but upon the postback the result does not get returned to the browser for some odd reason. I wasen't sure if it was because I was using MVC 2.0 and jQuery 1.4.1 and it differs to the MVC 1.0 version and jQuerys 1.3.2 version. . this is the code sections Controller public JsonResult StringReturn() { NameDTO myName = new NameDTO(); myName.nameID = 1; myName.name= "James"; myName.nameDescription = "Jmaes"; return Json(myName); } View with JQuery <script type="text/javascript"> $(document).ready(function () { $("#myButton").click(function () { $.getJSON("Home/StringReturn/", null, function (data) { alert(data.name); $("#show").append($("<div>" + data.name + "</div>")); }); }); }); </script> HTML <input type="button" value="clickMe" id="myButton"/> <div id="show">d</div>

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• Best strategy for moving data between physical tiers in ASP.net

  - by Pete Lunenfeld

  Building a new ASP.net application, and planning to separate DB, 'service' tier and Web/UI tier into separate physical layers. What is the best/easiest strategy to move serialized objects between the service tier and the UI tier? I was considering serializing POCOs into JSON using simple ASP.net pages to serve the middle tier. Meaning that the UI/Web tier will request data from a (hidden to the outside user) web server that will return a JSON string. This kind of JSON 'emitter' seems easily testable. It also seems easily compressible for efficiently moving data over the WAN between tiers. I know that some folks use .asmx webservices for this kind of task, but this seems like there is excess overhead with SOAP, and the package is not as human readable (testable) as POCOs serialized as JSON. Others are using more complex technology like WCF which we have never used. Does anyone have advice for choosing a method for moving data/objects between the data (db) tier and the web (UI) tier over the WAN using .net technologies? Thanks!!!

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• When should I be cautious using 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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