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  • Calculating average (AVG) and grouping by week on large data set takes too long

    - by caioiglesias
    I'm getting average prices by week on 7 million rows, it's taking around 30 seconds to get the job done. This is the simple query: SELECT AVG(price) as price, yearWEEK(FROM_UNIXTIME(timelog)) as week from pricehistory where timelog > $range and product_id = $id GROUP BY week The only week that actually gets data changed and is worth averaging every time is always the last one, so this calculation for the whole period is a waste of resources. I just wanted to know if mysql has a tool to help out on this.

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  • What's the name of the storage paradigm that uses cubes subdivided into 8 smaller cubes ad infinitum?

    - by Eric
    If I have a cube divided into 8 smaller cubes, each of which may be subdivided into a further 8 cubes, ad infinitum, what is the name of my system? I know that it's a special case of a tree, where each brance contains exactly 8 other leaves/branches. I remember the name starting with "Oct", and there was a wikipedia article on it, but I honestly can't find it! Does anyone know what such a data structure is actually known as?

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  • Want to check fields for data fast.

    - by Tom
    We have a database setup that consists of two parts: a static structure, and dynamic additions. For each database, the dynamic can be different, and sometimes we don't have data for all the dynamic fields. Rigt now, we check for empties by looking at the total count of records in the entire table, but we want to move to a more refined method of checking for empties if possible. Is it possible to quickly check through several hundred fields and see which ones are empty and which ones are populated?

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  • Go - Data types for validation

    - by nevalu
    How to create a new data type for Go which to can check/validate its schema when is created a new variable (of that type)? By example, to validate if a string has 20 characters, I tried: // Format: 2006-01-12T06:06:06Z func date(str string) { if len(str) != 20 { fmt.Println("error") } } var Date = date() type Account struct { domain string username string created Date } but it fails because Date is not a type.

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  • Hash Tables - Java

    - by Antony
    Am about to do a homework, and i need to store quite a lot of information (Dictionary) in a data structure of my choice. I heard people in my classroom saying hash-tables are the way to go. How come?

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  • MySQL Data Truncation: Out of range value in Performance test

    - by Khaledez
    on a test for Java-MySQL-Restlet application, I write to database at 4reqs/second for 120 seconds. In this write I insert a row that has foreign key which has the same value for all rows, and this exception occurs: Could not recover transaction. Original exception follows. com.mysql.jdbc.MysqlDataTruncation: Data truncation: Out of range value for column 'idPxxx' at row 1 Only 5% of requests fails to this exceptions, others works. Regards

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  • Mysql query to fetch data

    - by hnihar
    i have a table "request" with 4 columns namely: 1.recId :long primary key 2.interactionId:long 3.requestedBy:boolean 4.requestedType:boolean and data is as follows: VALUES (185,455699,0,5), (186,455746,0,1), (187,455746,1,1), (188,455752,0,1), (189,455753,0,1), (190,455753,1,1), (191,455754,1,1) i want a query to fetch all the rows where interactionId is same and having requestedBy both 1 and 0 values and requestType=1; regards, Nihar

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  • What data actually gets cached in InnoDB/MySQL?

    - by ming yeow
    Hi folks, i am trying to optimize performance for my database. My question is - what get cached in the db memory? For example: (table with 2 columns: key (indexed), data (not indexed) updated (not indexed) Select * where updated=20100202 (the db will do a scan - will the scanned rows be kept in memory?) Select * where key = 20 (the db will refer to the index - will the identified rows be kept in memory?)

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  • jqgrid modify data returned from ajax call before display in table

    - by user954211
    I have to display some data that I receive from the server as json object like this {"rowndx":"0","rows":"25","rowstotal":"100","rowsdata":[ ["00","DEVICE001","T0_IHOME","1","***","1","10"], ["01","DEVICE002","NO_DEVICE","1","***","1","10"], ["02","DEVICE003","NO_DEVICE","0","***","1","10"], ..... Before displaying the received data in a table I would like to make changes where necessary adding units to the numbers or replacing the numbers with words (eg 0 -OFF 1- ON) To do this I have associated at the ajax option "success" my encoding function. In this case, however, remains always visible the message "Loading ..." and no other action is permitted. I moved my re-encoding procedure to the "complete" ajax option and this time it seems to work. But I did not understand what was my mistake and I do not know if my procedure can work. This is my table ajax configuration url : "devtbl.json", mtype : "POST", datatype : "json", postData : ...... ajaxGridOptions: { type : 'post', contentType: 'application/json', async : false, complete : DEVparse_serverdata, error : function() { alert('Something bad happened. Stopping');}, }, jsonReader : { root : "tablerows", page : "currentpage", total : "totalpages", records : "totalrecords", cell : "", id : "0", userdata : "userdata", repeatitems : true }, and my coding function function DEVparse_serverdata(js , textStatus) { var jsontablereply = {} ; var rowsxpage_int = parseInt(UB.rowsxpage.DEVtable) ; var jsonreply = jQuery.parseJSON(js.responseText) ; jsontablereply.currentpage = "" + (1 + (parseInt(jsonreply.rowndx) / rowsxpage_int)); jsontablereply.totalpages = "" + parseInt((parseInt(jsonreply.rowstotal) + (rowsxpage_int-1)) / rowsxpage_int) ; jsontablereply.totalrecords = jsonreply.rowstotal; jsontablereply.tablerows = [] ; $.each(jsonreply.rowsdata, function(ndx, row) { var rowarray = [] ; rowarray[0] = row[0] ; rowarray[1] = row[1] ; rowarray[2] = row[2] ; rowarray[3] = row[3] ; rowarray[4] = row[4] ; switch (row[2]) { case "NO_DEVICE": rowarray[5] = "***" ; break ; case "T0_IHOME": rowarray[5] = "T=" + row[5] + "°C" ; break ; } jsontablereply.tablerows[ndx] = rowarray ; }) ; // each jQuery("#DEVtbl")[0].addJSONData(jsontablereply); } (I am a beginner with Jquery my coding style is poor)

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  • thresholding to distinguish small features in noisy data

    - by Daniel
    Hi, I'm wondering what type of threshold would work well for distinguishing features that are very small (small in the xy sense) in comparison with the full spread, if that makes sense. The graythresh() function in Matlab that uses the Otsu method doesn't work too well for my data. Otsu is a clustering method where I think the # of pixels should be similar in each class, which is not the case for me so when I employ it I get a threshold that is way too small and falls well within a lot of the background noise that remains even after filtering.

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  • How to handle UIPickerView with two data sources?

    - by devb0yax
    Hi, is it possible to handle two data sources in the UIPickerView? I have here a segmented control that would control the display of the picker view. So, for example, when first segment is clicked, the picker will display person's name. Then, when second segment is clicked, picker will display place's name. Thanks

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  • FormsAuthentication AuthCookie data type

    - by FreshCode
    Does the original data type of the username string in a call to FormsAuthentication.SetAuthCookie(...) make any difference with regards to security or code maintainability? As I understand it, the cookie is encrypted and used to identify a user on each request. I'm curious whether it should affect the design of the primary key on my Users table in my database, eg. Guid vs int or a unique username string.

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  • Retrieving Data in A NSTableView

    - by Heisennberg
    I have a three column Table View populated by two NSMutableDictionaries which share the same keys (ie key | value1 | value2 ) with dict1(key,value1) and dict2(key,value2). I want to manually enter data in the third column and create the key/value objects in dict2. But when I do that, my code picks the wrong key :S Here's the code for the delegate : - (void)tableView:(NSTableView *)aTableView setObjectValue:(id)anObject forTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex { if ([[aTableColumn identifier] isEqualToString:@"value2"]) { [dict2 setValue:anObject forKey:[[[aTableView tableColumnWithIdentifier:@"key"] dataCellForRow:rowIndex] stringValue ]]; } } Any idea ?

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  • Android - Retrieve all data from a SQLite table row

    - by Paul
    I have searched and cannot find an answer to my issue so i hope i am not completely barking up the wrong tree (so to speak). I am new to android and have started to create an app. My app on one screen creates and adds entries to a SQLite database using public class DatabaseHandler extends SQLiteOpenHelper and this all appears to work. I retrieve all the data and populate it into a grid, again this now works. My issue is I am unable to retrieve one complete line from the grid. I populate/display the grid with the following code. I have cut a lot out as the grid is made in stages, header, blank lines etc but the grid does display as I want. The id’s work as when I touch a line it displays its unique id. The onClick is right at the end and when I use getText() instead of getID() all it returns is the data in the labelDate. How do I retrieve all the labels as listed below? TextView labelDATE = new TextView(this); TextView labelCP = new TextView(this); TextView labelBG = new TextView(this); TextView labelQA = new TextView(this); TextView labelCN = new TextView(this); TextView labelKT = new TextView(this); TextView[] tvArray = {labelDATE, labelCP, labelBG, labelQA, labelCN, labelKT}; labelDATE.setText(re.getTime()); labelCP.setText(re.getCP()); labelBG.setText(re.getBG()); labelQA.setText(re.getQA()); labelCN.setText(re.getCN()); labelKT.setText(re.getKT()); for (TextView tv : tvArray) { tv.setTextColor(Color.WHITE); tv.setId(200+count); tr.setOnClickListener(this); tr.addView(tv); } //add this to the table row tl.addView(tr, new TableLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT)); public void onClick(View v) { if (v instanceof TableRow) { TableRow row = (TableRow) v; TextView child = (TextView) row.getChildAt(0); Toast toast = Toast.makeText(this, String.valueOf(child.getId()), Toast.LENGTH_SHORT); toast.show(); } } I can supply all the code for the grid creation if required. Thanks for any help.

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  • sending data from appcontroller to default.ctp - CakePHP

    - by Astral Projection Forum
    I want to send the below data to default.ctp, I want to display menus in all the pages, I'm using Auth, The problem is if I'm logged in I get the Menus correctly, but if I logout, I'm getting error saying variable'$topMenu' not found. The MenuController can be accessed only if logged in. $this->loadModel('Menu'); $this->set('topMenu',$this->Menu->find('all')); Any help on how to solve this?

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  • Are cookies enough for storing login data? (PHP)

    - by jpjp
    I am reading the Head First PHP/Mysql book and they say to store both the user's username, email into cookies and sessions. Is it safe to assume that everyone know a day has cookies? Or should I store both in sessions and cookies? I am not storing any sensitive data in cookies such as password, etc.

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