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  • 'Good' programming form in maintaining / updating / accessing files by entry

    - by zhermes
    Basic Question: If I'm storying/modifying data, should I access elements of a file by index hard-coded index, i.e. targetFile.getElement(5); via a hardcoded identifier (internally translated into index), i.e. target.getElementWithID("Desired Element"), or with some intermediate DESIRED_ELEMENT = 5; ... target.getElement(DESIRED_ELEMENT), etc. Background: My program (c++) stores data in lots of different 'dataFile's. I also keep a list of all of the data-files in another file---a 'listFile'---which also stores some of each one's properties (see below, but i.e. what it's name is, how many lines of information it has etc.). There is an object which manages the data files and the list file, call it a 'fileKeeper'. The entries of a listFile look something like: filename , contents name , number of lines , some more numbers ... Its definitely possible that I may add / remove fields from this list --- but in general, they'll stay static. Right now, I have a constant string array which holds the identification of each element in each entry, something like: const string fileKeeper::idKeys[] = { "FileName" , "Contents" , "NumLines" ... }; const int fileKeeper::idKeysNum = 6; // 6 - for example I'm trying to manage this stuff in 'good' programatic form. Thus, when I want to retrieve the number of lines in a file (for example), instead of having a method which just retrieves the '3'rd element... Instead I do something like: string desiredID = "NumLines"; int desiredIndex = indexForID(desiredID); string desiredElement = elementForIndex(desiredIndex); where the function indexForID() goes through the entries of idKeys until it finds desiredID then returns the index it corresponds to. And elementForIndex(index) actually goes into the listFile to retrieve the index'th element of the comma-delimited string. Problem: This still seems pretty ugly / poor-form. Is there a way I should be doing this? If not, what are some general ways in which this is usually done? Thanks!

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  • Beginner having difficulty with SQL query

    - by Vulcanizer
    Hi, I've been studying SQL for 2 weeks now and I'm preparing for an SQL test. Anyway I'm trying to do this question: For the table: 1 create table data { 2 id int, 3 n1 int not null, 4 n2 int not null, 5 n3 int not null, 6 n4 int not null, 7 primary key (id) 8 } I need to return the relation with tuples (n1, n2, n3) where all the corresponding values for n4 are 0. The problem asks me to solve it WITHOUT using subqueries(nested selects/views) It also gives me an example table and the expected output from my query: 01 insert into data (id, n1, n2, n3, n4) 02 values (1, 2,4,7,0), 03 (2, 2,4,7,0), 04 (3, 3,6,9,8), 05 (4, 1,1,2,1), 06 (5, 1,1,2,0), 07 (6, 1,1,2,0), 08 (7, 5,3,8,0), 09 (8, 5,3,8,0), 10 (9, 5,3,8,0); expects (2,4,7) (5,3,8) and not (1,1,2) since that has a 1 in n4 in one of the cases. The best I could come up with was: 1 SELECT DISTINCT n1, n2, n3 2 FROM data a, data b 3 WHERE a.ID <> b.ID 4 AND a.n1 = b.n1 5 AND a.n2 = b.n2 6 AND a.n3 = b.n3 7 AND a.n4 = b.n4 8 AND a.n4 = 0 but I found out that also prints (1,1,2) since in the example (1,1,2,0) happens twice from IDs 5 and 6. Any suggestions would be really appreciated.

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  • Time calculations with MySQL TIMEDIFF

    - by Oli
    Hi there, I have the following table: mysql> SELECT id,start1,stop1,start2,stop2 FROM times; +----+---------------------+---------------------+---------------------+---------------------+ | id | start1 | stop1 | start2 | stop2 | +----+---------------------+---------------------+---------------------+---------------------+ | 4 | 2010-04-23 08:05:00 | 2010-04-23 12:15:00 | 2010-04-23 12:45:00 | 2010-04-23 16:50:00 | | 2 | 2010-04-26 09:30:00 | 2010-04-26 12:10:00 | 2010-04-26 12:50:00 | 2010-04-26 16:50:00 | | 7 | 2010-04-28 08:45:00 | 2010-04-28 11:45:00 | 2010-04-28 13:10:00 | 2010-04-28 17:29:00 | | 6 | 2010-04-27 09:30:00 | 2010-04-27 12:15:00 | 2010-04-27 12:55:00 | 2010-04-27 18:44:00 | +----+---------------------+---------------------+---------------------+---------------------+ I want to sum total worktime and the difference to the "needed work hours". It works pretty well with the statement below, but for unknown reasons it doesn't work for id 6. start*/stop* fields are in format datetime. SELECT *, TIME_FORMAT(TIMEDIFF(totaltime,'08:24'),'%H:%i') AS diff, totaltime > '08:24' AS redorgreen FROM ( SELECT DATE_FORMAT(start1,'%a %e. %M %Y') AS date, TIME_FORMAT(SUM(TIMEDIFF(stop1,start1) + TIMEDIFF(stop2,start2)),'%H:%i') AS totaltime, TIME_FORMAT(start1,'%H:%i') AS start1, TIME_FORMAT(stop1,'%H:%i') AS stop1, TIME_FORMAT(start2,'%H:%i') AS start2, TIME_FORMAT(stop2,'%H:%i') AS stop2, id as id FROM times GROUP BY id ASC ) AS somethingwedontneed; This is the result: select id, TIME_FORMAT(SUM(TIMEDIFF(stop1,start1) + TIMEDIFF(stop2,start2)),'%H:%i') AS totaltime from times group by id; +----+-----------+ | id | totaltime | +----+-----------+ | 2 | 06:40 | | 4 | 08:15 | | 6 | NULL | | 7 | 07:19 | +----+-----------+ Thanks in advance for every hint.

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  • PHP login, getting wrong count value from query / fetch array

    - by Chris
    Hello, *EDIT*Thanks to the comments below it has been figured out that the problem lies with the md5, without everything works as it should. But how do i implent the md5 then? I am having some troubles with the following code below to login. The database and register system are already working. The problem lies that it does not find any result at all in the query. IF the count is 0 it should redirect the user to a secured page. But this only works if i write count = 0, but this should be 0 , only if the user name and password is found he should be directed to the secure (startpage) of the site after login. For example root (username) root (password) already exists but i cannot seem to properly login with it. <?php session_start(); if (!empty($_POST["send"])) { $username = ($_POST["username"]); $password = (md5($_POST["password"])); $count = 0; $con = mysql_connect("localhost" , "root", ""); mysql_select_db("testdb", $con); $result = mysql_query("SELECT name, password FROM user WHERE name = '".$username."' AND password = '".$password."' ") or die("Error select statement"); $count = mysql_num_rows($result); if($count > 0) // always goes the to else, only works with >=0 but then the data is not found in the database, hence incorrect { $row = mysql_fetch_array($result); $_SESSION["username"] = $row["name"]; header("Location: StartPage.php"); } else { echo "Wrong login data, please try again"; } mysql_close($con); } ?>

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  • mysql with 3 group by and sum

    - by cyberfly
    Hi all I have this data in my table (tb_cash_transaction) I want to group the TYPE column, CURRENCY_ID column and AMOUNT column so it will become like below: **Currency** **Cash IN** **Cash OUT** **Balance** 14 40000 30000 10000 15 50000 40000 10000 Rule : 1.Group by currency 2.Then find the sum of cash in for that currency 3.Find the sum of cash out for that currency 4.Get the balance (sum cash in - sum cash out) How to achieve it using mysql? I try using group by but cannot get the desired output. Thanks in advance

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  • Is it possible to select data with max value for a column using Criteria in Hibernate?

    - by Palo
    Lets say I have the following mapping: <hibernate-mapping package="mypackage"> <class name="User" table="user"> <id name="id" column="id"> <generator class="native"></generator> </id> <property name="name" /> <property name="age" /> </class> </hibernate-mapping> Is it possible to select the oldest user (that is age is maximal) using Criteria in Hibernate? I can imagine that i could do this with 2 selects. (first select total number of users and then order the entries descending by age and select the first entry). But is it possible with a single select? Thank you Palo

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  • Running sql scripts against an attached database?

    - by Will
    I've got an MDF attached to an instance of Sql Server 2008 Express, and I need to run some sql scripts against it to generate tables, indexes, etc. But I can't figure out how to get this to work. If I load the scripts in Visual Studio, it only allows me to connect to the server and run it against a database. I can't choose a different provider (Microsoft Sql Server Database File), so I can't select my MDF. This leaves me the only option of running the script as individual queries, but that won't work as it appears it doesn't support TSQL CREATE statements. How can I run my sql script against an attached database?

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  • wanted to get all dates in mysql result

    - by PankajK
    I have mysql table called user(id, name, join_on) join on is a date field what I want is to show in each day how many uses has been created I can use group by but it will only give me the dates when users get added like if date 4/12/10 5 users added 4/13/10 2 users added 4/15/10 7 users added here date 4/14/10 is missing and I want listing of all dates in one month. I have one solution for it by creating another table only for adding date and that table will left join my users table on join_on and will give total result but I don't want to do that as for creating that I need to create and add entries in date table please suggest the different approach for doing so. Thank you.

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  • Select Query Joined on Two Fields?

    - by btollett
    I've got a few tables in an access database: ID | LocationName 1 | Location1 2 | Location2 ID | LocationID | Date | NumProductsDelivered 1 | 1 | 12/10 | 3 2 | 1 | 01/11 | 2 3 | 1 | 02/11 | 2 4 | 2 | 11/10 | 1 5 | 2 | 12/10 | 1 ID | LocationID | Date | NumEmployees | EmployeeType 1 | 1 | 12/10 | 10 | 1 (=Permanent) 2 | 1 | 12/10 | 3 | 2 (=Temporary) 3 | 1 | 12/10 | 1 | 3 (=Support) 4 | 2 | 10/10 | 1 | 1 5 | 2 | 11/10 | 2 | 1 6 | 2 | 11/10 | 1 | 2 7 | 2 | 11/10 | 1 | 3 8 | 2 | 12/10 | 2 | 1 9 | 2 | 12/10 | 1 | 3 What I want to do is pass in the LocationID as a parameter and get back something like the following table. So, if I pass in 2 as my LocationID, I should get: Date | NumProductsDelivered | NumPermanentEmployees | NumSupportEmployees 10/10 | | 1 | 11/10 | 1 | 2 | 1 12/10 | 1 | 2 | 1 It seems like this should be a pretty simple query. I really don't even need the first table except as a way to fill in the combo box on the form from which the user chooses which location they want a report for. Unfortunately, everything I've done has resulted in me getting a lot more data than I should be getting. My confusion is in how to set up the join (presumably that's what I'm looking for here) given that I want both the date and locationID to be the same for each row in the result set. Any help would be much appreciated. Thanks.

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  • Some ASP.NET and Access

    - by Fazleh
    Good Day all, I have a big problem but i think its minor for you guys in Stackoverflow. I am creating a web application that has two main parts. The Payment part and Requisition part. It backbone is using access and the script is in ASP.NET. I managed to sort out most of the application. But I have been having a few problems. I have pasted the link to the project in http://www.mediafire.com/download/p09fefreifidud3/Inyatsi.rar so it will be easy for someone to see what I am blabbing about. Now for my problems: The AddRequisition.aspx/AddPayment.aspx: both have a reference number. I wanted it to be unique number(but not a primary key). I wanted it to be in the following format: DDMMYY(TransactionNo)(UserID) eg: 24061101PK. I have tried and tried but have not been able to sort it out. The AmountINWords gets the value from Amount. It converts the Amount into words. Thats not all. It picks what currncy was picked in the CurrencyPaidIn and pust the respective currency inside. eg. 123.45 USD becomes One Hundred and twenty three dollars and forty five cents. I tried using queries but as you will see that went all wrong. Those are the only two things that I cant seem to get my head around. I do know that there are some things that are not conventional ASP.NET and some text boxes are not the right size. I was thinking of sorting out those after I get those two fixed because they are simple to do. I really need some help with this application please. If someone can just have a look at the code and add a few things here and there. Thanks in advance. Faz

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  • reverse many to many fields in Django + count them

    - by cleliodpaula
    I'm trying to figure out how to solve this class Item(models.Model): type = models.ForeignKey(Type) name = models.CharField(max_lenght = 10) ... class List(models.Model): items = models.ManyToManyField(Item) ... I want to count how many an Item appears in another Lists, and show on template. view def items_by_list(request, id_): list = List.objects.get(id = id_) qr = list.items.all() #NOT TESTED num = [] i = 0 for item in qr: num[i] = List.objects.filter(items__id = item__id ).count() #FINISH NOT TESTED c = {} c.update(csrf(request)) c = {'request':request, 'list' : qr, 'num' : num} return render_to_response('items_by_list.html', c, context_instance=RequestContext(request)) template {% for dia in list %} <div class="span4" > <div> <h6 style="color: #9937d8">{{item.type.description}}</h6> <small style="color: #b2e300">{{ item.name }}</small> <small style="color: #b2e300">{{COUNT HOW MANY TIMES THE ITEM APPEAR ON OTHER LISTS}}</small> </div> {% endfor %} This seems to be easy, but I could not implement yet. If anyone has some glue to me, please help me. Thanks in advance.

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  • Not sure how to use Decode, NVL, and/or isNull (or something else?) in this situation

    - by RSW
    I have a table of orders for particular products, and a table of products that are on sale. (It's not ideal database structure, but that's out of my control.) What I want to do is outer join the order table to the sale table via product number, but I don't want to include any particular data from the sale table, I just want a Y if the join exists or N if it doesn't in the output. Can anyone explain how I can do this in SQL? Thanks in advance!

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  • how to compare the values inside a table in sql

    - by Ranjana
    how to compare the values of same table(say for eg: Order table) each and every time the record get inserted , if the record with same values get inserted already in same table i should not insert the new record with same values. how to do that exactly in sql server 2008

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  • android: error on SQLiteDatabase rawQuery (fetching data)

    - by Jin
    So I have a SQliteDatabase mDb. It only has one column, and its data are Strings for previously saved inputs. I'm trying to populate all the data from mDb into a String[] for AutoCompleteTextView (so that the autocomplete is based on previous inputs), and here's my code to get all of the String. public String[] fetchAllSearch() { ArrayList<String> allSearch = new ArrayList<String>(); Cursor c = mDb.rawQuery("select * from " + DATABASE_TABLE, null); c.moveToFirst(); if (c.getCount() > 0) { do { allSearch.add(c.getString(c.getColumnIndex("KEY"))); } while (c.moveToNext()); } String[] foo = (String[]) allSearch.toArray(); if (foo == null) { foo = new String[] {""}; } return foo; } my CREATE_TABLE command is private static final String DATABASE_CREATE = "create table " + DATABASE_TABLE; .. public void onCreate(SQLiteDatabase db) { db.execSQL(DATABASE_CREATE); } But for some reason the line mDb.rawQuery(...) is giving me "no such table found" exception, and for the life of me I can't figure out why. Any pointers?

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  • mysql count(*) left join group by - the number of files in a folder

    - by Flavius
    Hi I have the following tables CREATE TABLE `files` ( `fileid` int(11) NOT NULL AUTO_INCREMENT, `filename` varchar(255) NOT NULL, `filesize` int(11) NOT NULL, `folder` int(11) NOT NULL, PRIMARY KEY (`fileid`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; CREATE TABLE `folders` ( `directoryid` int(11) NOT NULL AUTO_INCREMENT, `directoryname` varchar(255) NOT NULL, PRIMARY KEY (`directoryid`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; How to get a list of all folders and the number of files they hold, including folders who have no (zero) files? Recursion must not be taken into account. Found it select folders.directoryid, folders.directoryname, count(files.fileid) as no_files from folders left join files on files.folder = folders.directoryid group by folders.directoryid, folders.directoryname I hope it will help someone.

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  • SQL: Optimize insensive SELECTs on DateTime fields

    - by Fedyashev Nikita
    I have an application for scheduling certain events. And all these events must be reviewed after each scheduled time. So basically we have 3 tables: items(id, name) scheduled_items(id, item_id, execute_at - datetime) - item_id column has an index option. reviewed_items(id, item_id, created_at - datetime) - item_id column has an index option. So core function of the application is "give me any items(which are not yet reviewed) for the actual moment". How can I optimize this solution for speed(because it is very core business feature and not micro optimization)? I suppose that adding index to the datetime fields doesn't make any sense because the cardinality or uniqueness on that fields are very high and index won't give any(?) speed-up. Is it correct? What would you recommend? Should I try no-SQL? -- mysql -V 5.075 I use caching where it makes sence.

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  • Joining tables, if percentage is above certain value

    - by CluelessGerman
    My question is similar to this one: Compare rows and get percentage However, little different. I adapted my question to the other post. I got 2 tables. First table: user_id | post_id 1 1 1 2 1 3 2 12 2 15 And second table: post_id | rating 1 1 1 2 1 3 2 1 2 5 3 null 3 1 3 4 12 4 15 1 So now I would like to count the rating for each post, in the second table. If the rating has more than, lets say, 50% positive ratings than I want to get the post_id and going it to the post_id from table one and add 1 to the user_id. At the end it would return the user_id with the number of positive posts. The result for above table would be: user_id | helpfulPosts 1 2 2 1 The post with post_id 1 and 3 have positive rating, because more than 50% have ratings of 1-3. The post with id = 2 is not positive, because the rating is exactly 50%. How would I achieve this? For clarification: It's a mysql rdbm and a positive post, is one where the number of rating_ids with 1, 2 and 3 are more than half of the overall rating. Basically the same thing, from the other thread I posted above.

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  • MySQL select/where statement

    - by expo101
    I have a webapplication linked to a mysql database with the following fields: field 1:trip_id field 2:trip_destination field 3:trip_description field 4:trip_duration In the webapplication I have a listbox based on the following: ListBox value =1: trip duration 1 - 5 days ListBox value =2: trip duration 6 - 10 days Listbox value =3: trip duration 11 -20 days ListBox value =4: trip duration over 20 days How do I put this in the sql select statement?

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  • MySQL: List rows who have one but not another many-to-many relationship

    - by Svish
    Not quite sure how to ask or define this, but can't figure it out. I have three tables like this: persons person_id, first_name, last_name hobbies hobby_id, name persons_hobbies person_id, hobby_id I need to make two lists. Persons that have both hobby A and B, and persons that have hobby A but not B. How can I write these two queries? Can't figure out how to do this with joining and all...

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  • Find Consecutive Rows & Calculate Duration

    - by MannyKo
    I have a set a of data that tells me if a couple of systems are available or not every 5 or 15 minutes increments. For now, the time increment shouldn't matter. The data looks like this: Status Time System_ID T 10:00 S01 T 10:15 S01 F 10:30 S01 F 10:45 S01 F 11:00 S01 T 11:15 S01 T 11:30 S01 F 11:45 S01 F 12:00 S01 F 12:15 S01 T 12:30 S01 F 10:00 S02 F 10:15 S02 F 10:30 S02 F 10:45 S02 F 11:00 S02 T 11:15 S02 T 11:30 S02 I want to create a view that tells when a system is NOT available (i.e. when it is F), from what time, to what time, and duration which is to - from. Desired results: System_ID From To Duration S01 10:30 11:00 00:30 S01 11:45 12:15 00:30 S02 10:00 11:00 01:00 Here is the script data: DROP SCHEMA IF EXISTS Sys_data CASCADE; CREATE SCHEMA Sys_data; CREATE TABLE test_data ( status BOOLEAN, dTime TIME, sys_ID VARCHAR(10), PRIMARY KEY (dTime, sys_ID) ); INSERT INTO test_data (status, dTime, sys_ID) VALUES (TRUE, '10:00:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (TRUE, '10:15:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '10:30:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '10:45:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '11:00:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (TRUE, '11:15:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (TRUE, '11:30:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '11:45:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '12:00:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '12:15:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (TRUE, '12:30:00', 'S01'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '10:00:00', 'S02'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '10:15:00', 'S02'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '10:30:00', 'S02'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '10:45:00', 'S02'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (FALSE, '11:00:00', 'S02'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (TRUE, '11:15:00', 'S02'); INSERT INTO test_data (status, dTime, sys_ID) VALUES (TRUE, '11:30:00', 'S02'); Thank you in advance!

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  • mysql_fetch_row() not a valid result resource

    - by user1717305
    I am confused, I don't know what's wrong. I'm about to transfer all data from my first table to the other. Here is my code: $getdata = mysql_query("SELECT Quantity, Description, Total FROM ordercart"); while($row = mysql_fetch_row($getdata)) { foreach($row as $cell){ $query1 = mysql_query("INSERT INTO ordermem (Quantity, Description, Total) VALUES ($cell)",$connect); } mysql_free_result($getdata); } I get the error: Warning: mysql_fetch_row(): 5 is not a valid MySQL result resource.

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