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  • What software design pattern is best for the following scenario (C#)

    - by askjdh
    I have a gps device that records data e.g. datetime, latitude, longitude I have an sdk that reads the data from the device. The way the data is read: A command packet (basically a combination of int values in a struct) is sent to the device. The device responds with the data in fixed size chunks e.g. 64bytes Depending on the command issued I will get back differect data structs e.g. sending command 1 to the device returns a struct like struct x { id int, name char[20] } command 2 returns a collection of the following structs (basically it boils down to an array of the structs - y[12]) struct y { date datetime, lat decimal, lon decimal } I would then want to convert the struct to a class and save the data to a database. What would be the best way to encapsulate the entire process, preferably using some established design pattern? Many thanks M

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  • Perform Grouping of Resultsets in Code, not on Database Level

    - by NinjaBomb
    Stackoverflowers, I have a resultset from a SQL query in the form of: Category Column2 Column3 A 2 3.50 A 3 2 B 3 2 B 1 5 ... I need to group the resultset based on the Category column and sum the values for Column2 and Column3. I have to do it in code because I cannot perform the grouping in the SQL query that gets the data due to the complexity of the query (long story). This grouped data will then be displayed in a table. I have it working for specific set of values in the Category column, but I would like a solution that would handle any possible values that appear in the Category column. I know there has to be a straightforward, efficient way to do it but I cannot wrap my head around it right now. How would you accomplish it? EDIT I have attempted to group the result in SQL using the exact same grouping query suggested by Thomas Levesque and both times our entire RDBMS crashed trying to process the query. I was under the impression that Linq was not available until .NET 3.5. This is a .NET 2.0 web application so I did not think it was an option. Am I wrong in thinking that? EDIT Starting a bounty because I believe this would be a good technique to have in the toolbox to use no matter where the different resultsets are coming from. I believe knowing the most concise way to group any 2 somewhat similar sets of data in code (without .NET LINQ) would be beneficial to more people than just me.

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  • Unit testing a controller method?

    - by Stefan Kendall
    I have a controller method like such: def search = { def query = params.query ... render results as JSON } How do I unit test this? Specifically, how do I call search to set params.query, and how do I test the results of the method render? Is there a way to mock the render method, perhaps?

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  • Batch commands execution order

    - by Dave18
    I'm looking to run a second batch command from .bat but after the first command has been done. REN "myfile.txt" "my_file.txt" start "title" "path" Here, I want the rename command to be executed before the process I wanted to start that has been terminated or executed. why it doesn't work in sequence order?

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  • How can I determine a file extension given a file path in LaTeX?

    - by Frank
    I am attempting to write a LaTeX package which leverages the minted package's \inputminted command. My \mycommand command takes two parameters, the first being a path to a file, and I want to pass the file's extension to the \inputminted command: \newcommand\mycommand[2]{ \inputminted{#1}{...} } Note that the above won't work since the full path is passed to \inputminted. Example: \mycommand{/path/to/Test.java}{blah} should invoke \inputminted{java}{...}

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  • IIS 7.5 powershell module usage issues

    - by pmcgrath
    Has anyone managed to use this module with success, i'm running 32bit Windows 7, where i have opened an administrator shell using run as administrator, i have imported the WebAdministration module and then attempted to use the commands with some issues, have provided two examples here Websites I created a web site with the following command new-website -name testsite -port 80 -hostheader testsite -physicalpath c:\temp Then i attempted to get the sites details using the command get-website -name testsite but it always returns all sites, seems to ignore the -name parameter. Only way i can get the site is using a filter get-website | ? { $_.name -eq 'testsite' } | get-member When i use appcmd it works as expected using the following command C:\> C:\Windows\System32\inetsrv\appcmd.exe list site testsite AppPools When i try to list the apppools using the following command dir iis:\apppools i get the following error Get-ChildItem : Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)) Yet when i use appcmd as follows i get all the apppools as expected without any error C:\Windows\System32\inetsrv\appcmd.exe list apppool Has anyone successfully managed to use the WebAdministration module ? Thanks in advance Pat

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  • How to improve INSERT INTO ... SELECT locking behavior

    - by Artem
    In our production database, we ran the following pseudo-code SQL batch query running every hour: INSERT INTO TemporaryTable (SELECT FROM HighlyContentiousTableInInnoDb WHERE allKindsOfComplexConditions are true) Now this query itself does not need to be fast, but I noticed it was locking up HighlyContentiousTableInInnoDb, even though it was just reading from it. Which was making some other very simple queries take ~25 seconds (that's how long that other query takes). Then I discovered that InnoDB tables in such a case are actually locked by a SELECT! http://www.mysqlperformanceblog.com/2006/07/12/insert-into-select-performance-with-innodb-tables/ But I don't really like the solution in the article of selecting into an OUTFILE, it seems like a hack (temporary files on filesystem seem sucky). Any other ideas? Is there a way to make a full copy of an InnoDB table without locking it in this way during the copy. Then I could just copy the HighlyContentiousTable to another table and do the query there.

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  • Syncing data between devel/live databases in Django

    - by T. Stone
    With Django's new multi-db functionality in the development version, I've been trying to work on creating a management command that let's me synchronize the data from the live site down to a developer machine for extended testing. (Having actual data, particularly user-entered data, allows me to test a broader range of inputs.) Right now I've got a "mostly" working command. It can sync "simple" model data but the problem I'm having is that it ignores ManyToMany fields which I don't see any reason for it do so. Anyone have any ideas of either how to fix that or a better want to handle this? Should I be exporting that first query to a fixture first and then re-importing it? from django.core.management.base import LabelCommand from django.db.utils import IntegrityError from django.db import models from django.conf import settings LIVE_DATABASE_KEY = 'live' class Command(LabelCommand): help = ("Synchronizes the data between the local machine and the live server") args = "APP_NAME" label = 'application name' requires_model_validation = False can_import_settings = True def handle_label(self, label, **options): # Make sure we're running the command on a developer machine and that we've got the right settings db_settings = getattr(settings, 'DATABASES', {}) if not LIVE_DATABASE_KEY in db_settings: print 'Could not find "%s" in database settings.' % LIVE_DATABASE_KEY return if db_settings.get('default') == db_settings.get(LIVE_DATABASE_KEY): print 'Data cannot synchronize with self. This command must be run on a non-production server.' return # Fetch all models for the given app try: app = models.get_app(label) app_models = models.get_models(app) except: print "The app '%s' could not be found or models could not be loaded for it." % label for model in app_models: print 'Syncing %s.%s ...' % (model._meta.app_label, model._meta.object_name) # Query each model from the live site qs = model.objects.all().using(LIVE_DATABASE_KEY) # ...and save it to the local database for record in qs: try: record.save(using='default') except IntegrityError: # Skip as the record probably already exists pass

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  • Why does LINQ-to-SQL Paging fail inside a function?

    - by ssg
    Here I have an arbitrary IEnumerable<T>. And I'd like to page it using a generic helper function instead of writing Skip/Take pairs every time. Here is my function: IEnumerable<T> GetPagedResults<T>(IEnumerable<T> query, int pageIndex, int pageSize) { return query.Skip((pageIndex - 1) * pageSize).Take(pageSize); } And my code is: result = GetPagedResults(query, 1, 10).ToList(); This produces a SELECT statement without TOP 10 keyword. But this code below produces the SELECT with it: result = query.Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList(); What am I doing wrong in the function?

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  • How to use function to connect to database and how to work with queries?

    - by Abhilash Shukla
    I am using functions to work with database.. Now the way i have defined the functions are as follows:- /** * Database definations */ define ('db_type', 'MYSQL'); define ('db_host', 'localhost'); define ('db_port', '3306'); define ('db_name', 'database'); define ('db_user', 'root'); define ('db_pass', 'password'); define ('db_table_prefix', ''); /** * Database Connect */ function db_connect($host = db_host, $port = db_port, $username = db_user, $password = db_pass, $database = db_name) { if(!$db = @mysql_connect($host.':'.$port, $username, $password)) { return FALSE; } if((strlen($database) > 0) AND (!@mysql_select_db($database, $db))) { return FALSE; } // set the correct charset encoding mysql_query('SET NAMES \'utf8\''); mysql_query('SET CHARACTER_SET \'utf8\''); return $db; } /** * Database Close */ function db_close($identifier) { return mysql_close($identifier); } /** * Database Query */ function db_query($query, $identifier) { return mysql_query($query, $identifier); } Now i want to know whether it is a good way to do this or not..... Also, while database connect i am using $host = db_host Is it ok? Secondly how i can use these functions, these all code is in my FUNCTIONS.php The Database Definitions and also the Database Connect... will it do the needful for me... Using these functions how will i be able to connect to database and using the query function... how will i able to execute a query? VERY IMPORTANT: How can i make mysql to mysqli, is it can be done by just adding an 'i' to mysql....Like:- @mysql_connect @mysqli_connect

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  • do's and don'ts for writing mysql queries

    - by nik
    One thing I always wonder while writing query is that am I writing most optimized query or not? I know certain things like: 1) using SELECT field1, filed2 instead of SELECT * 2) Giving proper indexes to the tables but I am sure there are more things that should be kept in mind for writing queries, since most of the database can only grow more and optimal query will help gr8 in execution time, Can u share some tips and tricks on writing queries?

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  • Strange things appear on running the program

    - by FILIaS
    Hey! I'm fixing a program but I'm facing a problem and I cant really realize what's the wrong on the code. I would appreciate any help. I didnt post all the code...but i think with this part you can get an idea of it. With the following function enter() I wanna add user commands' datas to a list. eg. user give the command: "enter james bond 007 gun" 'james' is supposed to be the name, 'bond' the surname, 007 the amount and the rest is the description. I use strtok in order to 'cut' the command,then i put each name on a temp array. Then i call InsertSort in order to put the datas on a linked list but in alphabetical order depending on the surname that users give. I wanna keep the list on order and put each time the elements on the right position. /* struct for all the datas that user enters on file*/ typedef struct catalog { char short_name[50]; char surname[50]; signed int amount; char description[1000]; struct catalog *next; }catalog,*catalogPointer; catalogPointer current; catalogPointer head = NULL; void enter(void)//user command: enter <name> <surname> <amount> <description> { int n,j=2,k=0; char temp[1500]; char command[1500]; while (command[j]!=' ' && command[j]!='\0') { temp[k]=command[j]; j++; k++; } temp[k]='\0'; char *curToken = strtok(temp," "); printf("temp is:%s \n",temp); char short_name[50],surname[50],description[1000]; signed int amount; //short_name=(char *)malloc(sizeof (char *)); //surname=(char *)malloc(sizeof (char *)); //description=(char *)malloc(sizeof (char *)); //amount=(int *)malloc(sizeof (int *)); printf("\nWhat you entered for saving:\n"); for (n = 0; curToken !='\0'; ++n) { if (curToken) { strncpy(short_name, curToken, sizeof (char *)); / } printf("Short Name: %s \n",short_name); curToken = strtok(NULL," "); if (curToken) strncpy(surname, curToken, sizeof (char *)); / printf("SurName: %s \n",surname); curToken = strtok(NULL," "); if (curToken) { char *chk; amount = (int) strtol(curToken, &chk, 10); if (!isspace(*chk) && *chk != 0) fprintf(stderr,"Warning: expected integer value for amount, received %s instead\n",curToken); } printf("Amount: %d \n",amount); curToken = strtok(NULL,"\0"); if (curToken) { strncpy(description, curToken, sizeof (char *)); } printf("Description: %s \n",description); break; } if (findEntryExists(head, surname) != NULL) printf("\nAn entry for <%s %s> is already in the catalog!\nNew entry not entered.\n",short_name,surname); else { printf("\nTry to entry <%s %s %d %s> in the catalog list!\n",short_name,surname,amount,description); InsertSort(&head,short_name, surname, amount, description); printf("\n**Entry done!**\n"); } // Maintain the list in alphabetical order by surname. } /********Uses special case code for the head end********/ void SortedInsert(catalog** headRef, catalogPointer newNode,char short_name[],char surname[],signed int amount,char description[]) { strcpy(newNode->short_name, short_name); strcpy(newNode->surname, surname); newNode->amount=amount; strcpy(newNode->description, description); // Special case for the head end if (*headRef == NULL||(*headRef)->surname >= newNode->surname) { newNode->next = *headRef; *headRef = newNode; } else { // Locate the node before the point of insertion catalogPointer current = *headRef; catalogPointer temp=current->next; while ( temp!=NULL ) { if(strcmp(temp->surname,newNode->surname)<0 ) current = temp; } newNode->next = temp; temp = newNode; } } // Given a list, change it to be in sorted order (using SortedInsert()). void InsertSort(catalog** headRef,char short_name[],char surname[],signed int amount,char description[]) { catalogPointer result = NULL; // build the answer here catalogPointer current = *headRef; // iterate over the original list catalogPointer next; while (current!=NULL) { next = current->next; // tricky - note the next pointer before we change it SortedInsert(&result,current,short_name,surname,amount,description); current = next; } *headRef = result; } Running the program I get these strange things (garbage?)... Choose your selection: enter james bond 007 gun Your command is: enter james bond 007 gun temp is:james What you entered for saving: Short Name: james SurName: Amount: 0 Description: 0T?? Try to entry james 0 0T?? in the catalog list! Entry done! Also I'm facing a problem on how to use the 'malloc' on this program. Thanks in advance. . .

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  • PHP calling PostgreSQL function - type issue?

    - by CitrusTree
    I have a function in PostgreSQL / plpgsql with the following signature: CREATE OR REPLACE FUNCTION user_login(TEXT, TEXT) RETURNS SETOF _get_session AS $$ ... $$ Where _get_session is a view. The function works fine when calling it from phpPgAdmin, however whan I call it from PHP I get the following error: Warning: pg_query() [function.pg-query]: Query failed: ERROR: type "session_ids" does not exist CONTEXT: compile of PL/pgSQL function "user_login" near line 2 in /home/sites/blah.com/index.php on line 69 The DECLARE section of the function contains the following variables: oldSessionId session_ids := $1; newSessionId session_ids := $2; The domain session_ids DOES exist, and other functions which use the same domain work when called from the same script. The PHP is as follows: $query = "SELECT * FROM $dbschema.user_login('$session_old'::TEXT, '$session'::TEXT)"; $result = pg_query($login, $query); I have also tried this using ::session_ids in place of ::TEXT when calling the function, however I recieve the same error. Help :o(

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  • DBLinq not generating where clause

    - by sipwiz
    I'm testing out DBLinq-0.18 and DBLinq from SVN Trunk with MySQL and Postgresql. I'm only using a very simple query but on both database DBLinq is not generating a Where clause. I have confirmed this by turning on statement logging on Postgresql to check exactly what request DBLinq is sending. My Linq query is: MyDB db = new MyDB(new NpgsqlConnection("Database=database;Host=localhost;User Id=postgres;Password=password")); var customers = from customer in db.Customers where customer.CustomerUserName == "test" select customer; The query works ok but the SQL generated by DBLinq is of the form: select customerusername, customerpassword .... from public.customers There is no Where clause which means DBLinq must be pulling the whole table down before running the Linq query. Has anyone had any experience with DBLinq and know what I could be doing wrong?

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  • How do I stop Mercurial's "hg serve -d" service under Windows?

    - by Joel
    I'm technically savvy but don't have extensive experience with servers/daemons (I'm a Windows guy, so...command lines intimidate me). I started a Mercurial server using the hg serve -d command, and all was well. Now, I want to stop it, and can't find a process to kill. Does anybody know the process name or a relatively simply CLI command to get it done?

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  • Open an attachment for editing and save changes made to it

    - by Seitaridis
    My Lotus Notes document has a rich text item that stores an attachment. I want to edit the attachment and after this to save the attachment back to the Lotus Notes document. This is the script that launches the attachment: @Command([EditGotoField];"Attachment"); @Command([EditSelectAll]); @Command([AttachmentLaunch]); @Command([EditDeselectAll]) This script opens the attachment, but the changes made are not reflected to the Lotus Document. One way of solving this is to add AttachmentActionDefault=2 as an entry to the notes.ini. This enables to edit the attachment when double clicking on attachment. Also using the right click on the attachment, and then choosing edit action, produces the same result. In both cases, after saving, the changes are reflected back to the Lotus Notes document. The problem is that I want to use a button for opening the attachment.

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  • MVVM-Light EventToCommand Behavior for CheckBox Checked/Unchecked in Silverlight

    - by George Durzi
    I would like to handle the Checked and Unchecked events of a Checkbox control and execute a command in my ViewModel. I wired up an EventTrigger for both the Checked and Unchecked events as follows: <CheckBox x:Name="chkIsExtendedHr" IsChecked="{Binding Schedule.Is24Hour, Mode=TwoWay}"> <i:Interaction.Triggers> <i:EventTrigger EventName="Checked"> <GalaSoft_MvvmLight_Command:EventToCommand CommandParameter="{Binding IsChecked, ElementName=chkIsExtendedHr}" Command="{Binding Path=SetCloseTime, Mode=OneWay}" /> </i:EventTrigger> <i:EventTrigger EventName="Unchecked"> <GalaSoft_MvvmLight_Command:EventToCommand CommandParameter="{Binding IsChecked, ElementName=chkIsExtendedHr}" Command="{Binding Path=SetCloseTime, Mode=OneWay}" /> </i:EventTrigger> </i:Interaction.Triggers> </CheckBox> I defined a RelayCommand in my ViewModel and wired up an action for it: public RelayCommand<Boolean> SetCloseTime{ get; private set; } ... SetCloseTime= new RelayCommand<bool>(ExecuteSetCloseTime); The parameter in the action for the command always resolves to the previous state of the CheckBox, e.g. false when the CheckBox is checked, and true when the CheckBox is unchecked. void ExecuteSetCloseTime(bool isChecked) { if (isChecked) { // do something } } Is this expected behavior? I have a workaround where I have separate triggers (and commands) for the Checked and Unchecked and use a RelayCommand instead of RelayCommand<bool>. Each command executes correctly when the CheckBox is checked and unchecked. Feels a little dirty though - even dirtier than having UI code in my ViewModel :) Thanks

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  • SQL: Join vs. subquery

    - by Col. Shrapnel
    I am an old-school MySQL user and always preferred JOIN over sub-query. But nowadays everyone uses sub-query and I hate it, dunno why. Though I've lack of theoretical knowledge to judge myself if there are any difference. Well, I am curious if sub-query as good as join and there is no thing to worry about?

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  • exec problem in sql 2005

    - by IordanTanev
    Hi, i have the situation where i have two databases whith same structure. The first have some data in its datatables. I need to create a script that will transfer the data from the first database to the second. I have created this script. DECLARE @table_name nvarchar(MAX), @query nvarchar(MAX) DECLARE @table_cursor CURSOR SET @table_cursor = CURSOR FAST_FORWARD FOR Select TABLE_NAME FROM INFORMATION_SCHEMA.TABLES OPEN @table_cursor FETCH NEXT FROM @table_cursor INTO @table_name WHILE @@FETCH_STATUS = 0 BEGIN SET @query = 'INSERT INTO ' + @table_name + ' SELECT * FROM MyDataBase.dbo.' + @table_name print @query exec @query FETCH NEXT FROM @table_cursor INTO @table_name END CLOSE @table_cursor DEALLOCATE @table_cursor The problem is that when i run th script the "print @query" statement prints statement like this INSERT INTO table SELECT * FROM MyDataBase.dbo.table When i copy this and run it from Management studio it works fine. But when the script trys to run it with exec i get this error Msg 911, Level 16, State 1, Line 21 Could not locate entry in sysdatabases for database 'INSERT INTO table SELECT * FROM MPDEV090314'. No entry found with that name. Make sure that the name is entered correctly. Hope someone can tell me whot is wront with this. Best Regards, Iordan Tanev

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  • How can I get mounted name and (Drive letter too) on Windows using python

    - by aberry
    I am using Daemon tool to mount an ISO image on Windows XP machine.I do mount using Daemon command (daemon.exe -mount 0,). Above command will mount ISO image to device number. In my case I have 4 partition (C,D,E,F) and G for DVD/CD-RW. Now what happen, ISO gets mounted to drive letter 'H:' with name (as defined while creating ISO) say 'testmount' My queries:- 1) How can I get mount name of mounted ISO image (i.e. 'testmount'). Just another case; if there are already some mount points existing on machine and I created a new one using Daemon tool. Then If I can get latest one using script that will be great. 2) How to get drive letter where it did get mounted. If anyone know python script or command (or even Win command ) to get these info. do let me know. Thanks...

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  • How to designing a generic databse whos layout may change over time?

    - by mawg
    Here's a tricky one - how do I programatically create and interrogate a database who's contents I can't really foresee? I am implementing a generic input form system. The user can create PHP forms with a WYSIWYG layout and use them for any purpose he wishes. He can also query the input. So, we have three stages: a form is designed and generated. This is a one-off procedure, although the form can be edited later. This designs the database. someone or several people make use of the form - say for daily sales reports, stock keeping, payroll, etc. Their input to the forms is written to the database. others, maybe management, can query the database and generate reports. Since these forms are generic, I can't predict the database structure - other than to say that it will reflect HTML form fields and consist of a the data input from collection of edit boxes, memos, radio buttons and the like. Questions and remarks: A) how can I best structure the database, in terms of tables and columns? What about primary keys? My first thought was to use the control name to identify each column, then I realized that the user can edit the form and rename, so that maybe "name" becomes "employee" or "wages" becomes ":salary". I am leaning towards a unique number for each. B) how best to key the rows? I was thinking of a timestamp to allow me to query and a column for the row Id from A) C) I have to handle column rename/insert/delete. Foe deletion, I am unsure whether to delete the data from the database. Even if the user is not inputting it from the form any more he may wish to query what was previously entered. Or there may be some legal requirements to retain the data. Any gotchas in column rename/insert/delete? D) For the querying, I can have my PHP interrogate the database to get column names and generate a form with a list where each entry has a database column name, a checkbox to say if it should be used in the query and, based on column type, some selection criteria. That ought to be enough to build searches like "position = 'senior salesman' and salary 50k". E) I probably have to generate some fancy charts - graphs, histograms, pie charts, etc for query results of numerical data over time. I need to find some good FOSS PHP for this. F) What else have I forgotten? This all seems very tricky to me, but I am database n00b - maybe it is simple to you gurus?

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  • Building Queries Systematically

    - by Jeremy Smyth
    The SQL language is a bit like a toolkit for data. It consists of lots of little fiddly bits of syntax that, taken together, allow you to build complex edifices and return powerful results. For the uninitiated, the many tools can be quite confusing, and it's sometimes difficult to decide how to go about the process of building non-trivial queries, that is, queries that are more than a simple SELECT a, b FROM c; A System for Building Queries When you're building queries, you could use a system like the following:  Decide which fields contain the values you want to use in our output, and how you wish to alias those fields Values you want to see in your output Values you want to use in calculations . For example, to calculate margin on a product, you could calculate price - cost and give it the alias margin. Values you want to filter with. For example, you might only want to see products that weigh more than 2Kg or that are blue. The weight or colour columns could contain that information. Values you want to order by. For example you might want the most expensive products first, and the least last. You could use the price column in descending order to achieve that. Assuming the fields you've picked in point 1 are in multiple tables, find the connections between those tables Look for relationships between tables and identify the columns that implement those relationships. For example, The Orders table could have a CustomerID field referencing the same column in the Customers table. Sometimes the problem doesn't use relationships but rests on a different field; sometimes the query is looking for a coincidence of fact rather than a foreign key constraint. For example you might have sales representatives who live in the same state as a customer; this information is normally not used in relationships, but if your query is for organizing events where sales representatives meet customers, it's useful in that query. In such a case you would record the names of columns at either end of such a connection. Sometimes relationships require a bridge, a junction table that wasn't identified in point 1 above but is needed to connect tables you need; these are used in "many-to-many relationships". In these cases you need to record the columns in each table that connect to similar columns in other tables. Construct a join or series of joins using the fields and tables identified in point 2 above. This becomes your FROM clause. Filter using some of the fields in point 1 above. This becomes your WHERE clause. Construct an ORDER BY clause using values from point 1 above that are relevant to the desired order of the output rows. Project the result using the remainder of the fields in point 1 above. This becomes your SELECT clause. A Worked Example   Let's say you want to query the world database to find a list of countries (with their capitals) and the change in GNP, using the difference between the GNP and GNPOld columns, and that you only want to see results for countries with a population greater than 100,000,000. Using the system described above, we could do the following:  The Country.Name and City.Name columns contain the name of the country and city respectively.  The change in GNP comes from the calculation GNP - GNPOld. Both those columns are in the Country table. This calculation is also used to order the output, in descending order To see only countries with a population greater than 100,000,000, you need the Population field of the Country table. There is also a Population field in the City table, so you'll need to specify the table name to disambiguate. You can also represent a number like 100 million as 100e6 instead of 100000000 to make it easier to read. Because the fields come from the Country and City tables, you'll need to join them. There are two relationships between these tables: Each city is hosted within a country, and the city's CountryCode column identifies that country. Also, each country has a capital city, whose ID is contained within the country's Capital column. This latter relationship is the one to use, so the relevant columns and the condition that uses them is represented by the following FROM clause:  FROM Country JOIN City ON Country.Capital = City.ID The statement should only return countries with a population greater than 100,000,000. Country.Population is the relevant column, so the WHERE clause becomes:  WHERE Country.Population > 100e6  To sort the result set in reverse order of difference in GNP, you could use either the calculation, or the position in the output (it's the third column): ORDER BY GNP - GNPOld or ORDER BY 3 Finally, project the columns you wish to see by constructing the SELECT clause: SELECT Country.Name AS Country, City.Name AS Capital,        GNP - GNPOld AS `Difference in GNP`  The whole statement ends up looking like this:  mysql> SELECT Country.Name AS Country, City.Name AS Capital, -> GNP - GNPOld AS `Difference in GNP` -> FROM Country JOIN City ON Country.Capital = City.ID -> WHERE Country.Population > 100e6 -> ORDER BY 3 DESC; +--------------------+------------+-------------------+ | Country            | Capital    | Difference in GNP | +--------------------+------------+-------------------+ | United States | Washington | 399800.00 | | China | Peking | 64549.00 | | India | New Delhi | 16542.00 | | Nigeria | Abuja | 7084.00 | | Pakistan | Islamabad | 2740.00 | | Bangladesh | Dhaka | 886.00 | | Brazil | Brasília | -27369.00 | | Indonesia | Jakarta | -130020.00 | | Russian Federation | Moscow | -166381.00 | | Japan | Tokyo | -405596.00 | +--------------------+------------+-------------------+ 10 rows in set (0.00 sec) Queries with Aggregates and GROUP BY While this system might work well for many queries, it doesn't cater for situations where you have complex summaries and aggregation. For aggregation, you'd start with choosing which columns to view in the output, but this time you'd construct them as aggregate expressions. For example, you could look at the average population, or the count of distinct regions.You could also perform more complex aggregations, such as the average of GNP per head of population calculated as AVG(GNP/Population). Having chosen the values to appear in the output, you must choose how to aggregate those values. A useful way to think about this is that every aggregate query is of the form X, Y per Z. The SELECT clause contains the expressions for X and Y, as already described, and Z becomes your GROUP BY clause. Ordinarily you would also include Z in the query so you see how you are grouping, so the output becomes Z, X, Y per Z.  As an example, consider the following, which shows a count of  countries and the average population per continent:  mysql> SELECT Continent, COUNT(Name), AVG(Population)     -> FROM Country     -> GROUP BY Continent; +---------------+-------------+-----------------+ | Continent     | COUNT(Name) | AVG(Population) | +---------------+-------------+-----------------+ | Asia          |          51 |   72647562.7451 | | Europe        |          46 |   15871186.9565 | | North America |          37 |   13053864.8649 | | Africa        |          58 |   13525431.0345 | | Oceania       |          28 |    1085755.3571 | | Antarctica    |           5 |          0.0000 | | South America |          14 |   24698571.4286 | +---------------+-------------+-----------------+ 7 rows in set (0.00 sec) In this case, X is the number of countries, Y is the average population, and Z is the continent. Of course, you could have more fields in the SELECT clause, and  more fields in the GROUP BY clause as you require. You would also normally alias columns to make the output more suited to your requirements. More Complex Queries  Queries can get considerably more interesting than this. You could also add joins and other expressions to your aggregate query, as in the earlier part of this post. You could have more complex conditions in the WHERE clause. Similarly, you could use queries such as these in subqueries of yet more complex super-queries. Each technique becomes another tool in your toolbox, until before you know it you're writing queries across 15 tables that take two pages to write out. But that's for another day...

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  • NHibernate FetchMode.Lazy

    - by RyanFetz
    I have an object which has a property on it that has then has collections which i would like to not load in a couple situations. 98% of the time i want those collections fetched but in the one instance i do not. Here is the code I have... Why does it not set the fetch mode on the properties collections? [DataContract(Name = "ThemingJob", Namespace = "")] [Serializable] public class ThemingJob : ServiceJob { [DataMember] public virtual Query Query { get; set; } [DataMember] public string Results { get; set; } } [DataContract(Name = "Query", Namespace = "")] [Serializable] public class Query : LookupEntity<Query>, DAC.US.Search.Models.IQueryEntity { [DataMember] public string QueryResult { get; set; } private IList<Asset> _Assets = new List<Asset>(); [IgnoreDataMember] [System.Xml.Serialization.XmlIgnore] public IList<Asset> Assets { get { return _Assets; } set { _Assets = value; } } private IList<Theme> _Themes = new List<Theme>(); [IgnoreDataMember] [System.Xml.Serialization.XmlIgnore] public IList<Theme> Themes { get { return _Themes; } set { _Themes = value; } } private IList<Affinity> _Affinity = new List<Affinity>(); [IgnoreDataMember] [System.Xml.Serialization.XmlIgnore] public IList<Affinity> Affinity { get { return _Affinity; } set { _Affinity = value; } } private IList<Word> _Words = new List<Word>(); [IgnoreDataMember] [System.Xml.Serialization.XmlIgnore] public IList<Word> Words { get { return _Words; } set { _Words = value; } } } using (global::NHibernate.ISession session = NHibernateApplication.GetCurrentSession()) { global::NHibernate.ICriteria criteria = session.CreateCriteria(typeof(ThemingJob)); global::NHibernate.ICriteria countCriteria = session.CreateCriteria(typeof(ThemingJob)); criteria.AddOrder(global::NHibernate.Criterion.Order.Desc("Id")); var qc = criteria.CreateCriteria("Query"); qc.SetFetchMode("Assets", global::NHibernate.FetchMode.Lazy); qc.SetFetchMode("Themes", global::NHibernate.FetchMode.Lazy); qc.SetFetchMode("Affinity", global::NHibernate.FetchMode.Lazy); qc.SetFetchMode("Words", global::NHibernate.FetchMode.Lazy); pageIndex = Convert.ToInt32(pageIndex) - 1; // convert to 0 based paging index criteria.SetMaxResults(pageSize); criteria.SetFirstResult(pageIndex * pageSize); countCriteria.SetProjection(global::NHibernate.Criterion.Projections.RowCount()); int totalRecords = (int)countCriteria.List()[0]; return criteria.List<ThemingJob>().ToPagedList<ThemingJob>(pageIndex, pageSize, totalRecords); }

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  • Build dynamic LINQ?

    - by d daly
    Hi Im using #LINQ# to query data, but can anyone tell me how to build the query dynamically, if the user only wants to report on say 1 of the 3 fields? (see below) Thanks DD var query = from cl in db.tblClaims join cs in db.tblCases on cl.ref_no equals cs.ref_no where cl.claim_status == "Appeal" && cl.appeal_date >= Convert.ToDateTime(txtReferedFromDate.Text) && cl.appeal_date <= Convert.ToDateTime(txtReferedToDate.Text) && cs.referred_from_lho == dlLHO.Text && cs.adviser == dlAdviser.Text select new { Ref = cs.ref_no, ClaimType = cl.claim_type, ClaimStatus = cl.claim_status, AppealDate = cl.appeal_date }; gvReport.DataSource = query;

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  • Masspay and MySql

    - by Mike
    Hi, I am testing Paypal's masspay using their 'MassPay NVP example' and I having difficulty trying to amend the code so inputs data from my MySql database. Basically I have user table in MySql which contains email address, status of payment (paid,unpaid) and balance. CREATE TABLE `users` ( `user_id` int(10) unsigned NOT NULL auto_increment, `email` varchar(100) collate latin1_general_ci NOT NULL, `status` enum('unpaid','paid') collate latin1_general_ci NOT NULL default 'unpaid', `balance` int(10) NOT NULL default '0', PRIMARY KEY (`user_id`) ) ENGINE=MyISAM AUTO_INCREMENT=6 DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci Data : 1 [email protected] paid 100 2 [email protected] unpaid 11 3 [email protected] unpaid 20 4 [email protected] unpaid 1 5 [email protected] unpaid 20 6 [email protected] unpaid 15 I then have created a query which selects users with an unpaid balance of $10 and above : $conn = db_connect(); $query=$conn->query("SELECT * from users WHERE balance >='10' AND status = ('unpaid')"); What I would like to is for each record returned from the query for it to populate the code below: Now the code which I believe I need to amend is as follows: for($i = 0; $i < 3; $i++) { $receiverData = array( 'receiverEmail' => "[email protected]", 'amount' => "example_amount",); $receiversArray[$i] = $receiverData; } However I just can't get it to work, I have tried using mysqli_fetch_array and then replaced "[email protected]" with $row['email'] and "example_amount" with row['balance'] in various methods of coding but it doesn't work. Also I need it to loop to however many rows that were retrieved from the query as <3 in the for loop above. So the end result I am looking for is for the $nvpStr string to pass with something like this: $nvpStr = "&EMAILSUBJECT=test&RECEIVERTYPE=EmailAddress&CURRENCYCODE=USD&[email protected]&L_Amt=11&[email protected]&L_Amt=11&[email protected]&L_Amt=20&[email protected]&L_Amt=20&[email protected]&L_Amt=15"; Thanks

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