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• Group / User based security. Table / SQL question

  - by Brett

  Hi, I'm setting up a group / user based security system. I have 4 tables as follows: user groups group_user_mappings acl where acl is the mapping between an item_id and either a group or a user. The way I've done the acl table, I have 3 columns of note (actually 4th one as an auto-id, but that is irrelevant) col 1 item_id (item to access) col 3 user_id (user that is allowed to access) col 3 group_id (group that is allowed to access) So for example item1, peter, , item2, , group1 item3, jane, , so either the acl will give access to a user or a group. Any one line in the ACL table with either have an item - user mapping, or an item group. If I want to have a query that returns all objects a user has access to, I think I need to have a SQL query with a UNION, because I need 2 separate queries that join like.. item - acl - group - user AND item - acl - user This I guess will work OK. Is this how its normally done? Am I doing this the right way? Seems a little messy. I was thinking I could get around it by creating a single user group for each person, so I only ever deal with groups in my SQL, but this seems a little messy as well..

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• What is happening in this T-SQL code? (Concatenting the results of a SELECT statement)

  - by Ben McCormack

  I'm just starting to learn T-SQL and could use some help in understanding what's going on in a particular block of code. I modified some code in an answer I received in a previous question, and here is the code in question: DECLARE @column_list AS varchar(max) SELECT @column_list = COALESCE(@column_list, ',') + 'SUM(Case When Sku2=' + CONVERT(varchar, Sku2) + ' Then Quantity Else 0 End) As [' + CONVERT(varchar, Sku2) + ' - ' + Convert(varchar,Description) +'],' FROM OrderDetailDeliveryReview Inner Join InvMast on SKU2 = SKU and LocationTypeID=4 GROUP BY Sku2 , Description ORDER BY Sku2 Set @column_list = Left(@column_list,Len(@column_list)-1) Select @column_list ---------------------------------------- 1 row is returned: ,SUM(Case When Sku2=157 Then Quantity Else 0 End) As [157 -..., SUM(Case ... The T-SQL code does exactly what I want, which is to make a single result based on the results of a query, which will then be used in another query. However, I can't figure out how the SELECT @column_list =... statement is putting multiple values into a single string of characters by being inside a SELECT statement. Without the assignment to @column_list, the SELECT statement would simply return multiple rows. How is it that by having the variable within the SELECT statement that the results get "flattened" down into one value? How should I read this T-SQL to properly understand what's going on?

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• Perl Unicode glitch

  - by RedGrittyBrick

  In this output, why am I getting extra newlines between lines b&c and d&e? a: ....v....1....v... (a) b: 'Budejovický Budvar' length 18 (b) c: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 (c) d: B u d e j o v i c k ý B u d v a r (d) e: 42 75 64 11b 6a 6f 76 69 63 6b fd 20 42 75 64 76 61 72 (e) from this program #!perl use strict; use warnings; binmode (STDOUT, "encoding(UTF-8)"); # so no "Wide characater in print" warning print "\n"; my $r = "Bud\N{U+011B}jovick\N{U+00FD} Budvar"; print "a: ....v....1....v... (a)\n"; print "b: '$r' length ", length($r)," (b)\n"; print "c:"; printf "%4d",$_ for (1..18); print " (c)\n"; print "d: "; print join(" ", split("", $r)); print " (d)\n"; print "e: "; printf "%*v3x", " ", $r; print " (e)\n";

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• PHP code displayed in browser

  - by Drake

  so, I'm working on a databases project, and i'm trying to code incrementally. the problem is, when i go to test the php in browser, it displays the php code after my use of "-". the html printing is displayed properly, which is AFTER the point where the - is. here is the php: <?php function getGraphicNovel(){ include_once("./connect.php"); $db_connection = new mysqli($SERVER, $USERNAME, $PASSWORD, $DATABASE); if (mysqli_connect_errno()) { echo("Can't connect to MySQL Server. Error code: " . mysqli_connect_error()); return null; } $stmt = $db_connection->stmt_init(); $returnValue = "invalid"; if($stmt.prepare("select series from graphic_novel_main natural join graphic_novel_misc")) { $stmt->execute(); $stmt->bind_result($series); while ($stmt->fetch()) { echo "<tr><td>" . $series . "</td></tr>"; } $stmt->close(); } $db_connection->close(); } getGraphicNovel(); ?> here is a link to the page. hopefully it works for people outside the school's network. http://plato.cs.virginia.edu/~paw5k/cainedb/viewall.html if anyone knows why this is happening, your input would be great!

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• rails named_scope issue with eager loading

  - by Craig

  Two models (Rails 2.3.8): User; username & disabled properties; User has_one :profile Profile; full_name & hidden properties I am trying to create a named_scope that eliminate the disabled=1 and hidden=1 User-Profiles. Moreover, while the User model is usually used in conjunction with the Profile model, I would like the flexibility to be able specify this using the :include = :profile syntax. I have the following User named_scope: named_scope :visible, { :joins => "INNER JOIN profiles ON users.id=profiles.user_id", :conditions => ["users.disabled = ? AND profiles.hidden = ?", false, false] } This works as expected when just reference the User model: >> User.visible.map(&:username).flatten => ["user a", "user b", "user c", "user d"] However, when I attempt to include the Profile model: User.visible(:include=> :profiles).profile.map(&:full_name).flatten I get an error that reads: NoMethodError: undefined method `profile' for #<User:0x1030bc828> Am I able to cross model-collection boundaries in this manner?

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• How to index a table with a Type 2 slowly changing dimension for optimal performance

  - by The Lazy DBA

  Suppose you have a table with a Type 2 slowly-changing dimension. Let's express this table as follows, with the following columns: * [Key] * [Value1] * ... * [ValueN] * [StartDate] * [ExpiryDate] In this example, let's suppose that [StartDate] is effectively the date in which the values for a given [Key] become known to the system. So our primary key would be composed of both [StartDate] and [Key]. When a new set of values arrives for a given [Key], we assign [ExpiryDate] to some pre-defined high surrogate value such as '12/31/9999'. We then set the existing "most recent" records for that [Key] to have an [ExpiryDate] that is equal to the [StartDate] of the new value. A simple update based on a join. So if we always wanted to get the most recent records for a given [Key], we know we could create a clustered index that is: * [ExpiryDate] ASC * [Key] ASC Although the keyspace may be very wide (say, a million keys), we can minimize the number of pages between reads by initially ordering them by [ExpiryDate]. And since we know the most recent record for a given key will always have an [ExpiryDate] of '12/31/9999', we can use that to our advantage. However... what if we want to get a point-in-time snapshot of all [Key]s at a given time? Theoretically, the entirety of the keyspace isn't all being updated at the same time. Therefore for a given point-in-time, the window between [StartDate] and [ExpiryDate] is variable, so ordering by either [StartDate] or [ExpiryDate] would never yield a result in which all the records you're looking for are contiguous. Granted, you can immediately throw out all records in which the [StartDate] is greater than your defined point-in-time. In essence, in a typical RDBMS, what indexing strategy affords the best way to minimize the number of reads to retrieve the values for all keys for a given point-in-time? I realize I can at least maximize IO by partitioning the table by [Key], however this certainly isn't ideal. Alternatively, is there a different type of slowly-changing-dimension that solves this problem in a more performant manner?

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• Doctrine/symfony: getSqlQuery() output in phpMyAdmin/SQL tab

  - by user248959

  Hi, i have created this query that works OK: $q1 = Doctrine_Query::create() ->from('Usuario u') ->leftJoin('u.AmigoUsuario a ON u.id = a.user2_id OR u.id = a.user1_id') ->where("a.user2_id = ? OR a.user1_id = ?", array($id,$id)) ->andWhere("u.id <> ?", $id) ->andWhere("a.estado LIKE ?", 1); echo $q1->getSqlQuery(); The calling to getSqlQuery outputs this clause: SELECT s.id AS s_id, s.username AS s_username, s.algorithm AS s_algorithm, s.salt AS s_salt, s.password AS s__password, s.is_active AS s__is_active, s.is_super_admin AS s__is_super_admin, s.last_login AS s__last_login, s.email_address AS s__email_address, s.nombre_apellidos AS s__nombre_apellidos, s.sexo AS s__sexo, s.fecha_nac AS s__fecha_nac, s.provincia AS s_provincia, s.localidad AS s_localidad, s.fotografia AS s_fotografia, s.avatar AS s_avatar, s.avatar_mensajes AS s__avatar_mensajes, s.created_at AS s__created_at, s.updated_at AS s__updated_at, a.id AS a__id, a.user1_id AS a__user1_id, a.user2_id AS a__user2_id, a.estado AS a__estado FROM sf_guard_user s LEFT JOIN amigo_usuario a ON ((s.id = a.user2_id OR s.id = a.user1_id)) WHERE ((a.user2_id = ? OR a.user1_id = ?) AND s.id < ? AND a.estado LIKE ?) If i take that clause to phpmyadmin SQL tab i get this error 1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '? OR a.user1_id = ?) AND s.id < ? AND a.estado LIKE ?) LIMIT 0, 30' at line 1 Why i'm getting this error? Regards Javi

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• How do I fully reload my Sencha Touch App when tapping 'refresh'?

  - by torr

  My list view layout is similar to Pinterest, with absolutely positioned blocks. Unfortunately, this seems to require a full re-initialization at refresh. If reload only the store (as below) the new blocks are incorrectly positioned. How do I reload the app when the user clicks on refresh? This is my View: Ext.require(['Ext.data.Store', 'MyApp.model.StreamModel'], function() { Ext.define('MyApp.view.HomeView', { extend: 'Ext.navigation.View', xtype: 'homepanel', requires: [ 'Ext.dataview.List', ], config: { title: 'Home', iconCls: 'home', styleHtmlContent: true, navigationBar: { items: [ { xtype: 'button', iconMask: true, iconCls: 'refresh', align: 'left', action: 'refreshButton' } ] }, items: { title: 'My', xtype: 'list', itemTpl: [ '<div class="post">', ... '</div>' ].join(''), store: new Ext.data.Store({ model: 'MyApp.model.StreamModel', autoLoad: true, storeId: 'stream' }), } } }); }); Model: Ext.define('MyApp.model.StreamModel', { extend: 'Ext.data.Model', config: { fields: [ 'post_id', 'comments' ], proxy: { type: 'jsonp', url: 'http://My.com/app', reader: { type: 'json', } } } }); and my Controller: Ext.define('MyApp.controller.RefreshController', { extend: 'Ext.app.Controller', requires: [ 'Ext.navigation.View' ], config: { control: { 'button[action=refreshButton]': { tap: 'refresh' } } }, refresh: function() { // Ext.StoreMgr.get('stream').load(); // here I'd like to reload the app instead // not just the store } });

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• Google app engine: Poor Performance with JDO + Datastore

  - by Bosh

  I have a simple data model that includes USERS: store basic information (key, name, phone # etc) RELATIONS: describe, e.g. a friendship between two users (supplying a relationship_type + two user keys) I'm getting very poor performance, for instance, if I try to print the first names of all of a user's friends. Say the user has 500 friends: I can fetch the list of friend user_ids very easily in a single query. But then, to pull out first names, I have to do 500 back-and-forth trips to the Datastore, each of which seems to take on the order of 30 ms. If this were SQL, I'd just do a JOIN and get the answer out fast. I understand there are rudimentary facilities for performing joins across un-owned relations in a relaxed implementation of JDO (as described at http://gae-java-persistence.blogspot.com) but they sound experimental and non-standard (e.g. my code won't work in any other JDO implementation). Is this really my best bet? Otherwise, how do people extract satisfactory performance from JDO/Datastore in this kind of (very common) situation? -Bosh

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• Weird MySQL behavior, seems like a SQL bug

  - by Daniel Magliola

  I'm getting a very strange behavior in MySQL, which looks like some kind of weird bug. I know it's common to blame the tried and tested tool for one's mistakes, but I've been going around this for a while. I have 2 tables, I, with 2797 records, and C, with 1429. C references I. I want to delete all records in I that are not used by C, so i'm doing: select * from i where id not in (select id_i from c); That returns 0 records, which, given the record counts in each table, is physically impossible. I'm also pretty sure that the query is right, since it's the same type of query i've been using for the last 2 hours to clean up other tables with orphaned records. To make things even weirder... select * from i where id in (select id_i from c); DOES work, and brings me the 1297 records that I do NOT want to delete. So, IN works, but NOT IN doesn't. Even worse: select * from i where id not in ( select i.id from i inner join c ON i.id = c.id_i ); That DOES work, although it should be equivalent to the first query (i'm just trying mad stuff at this point). Alas, I can't use this query to delete, because I'm using the same table i'm deleting from in the subquery. I'm assuming something in my database is corrupt at this point. In case it matters, these are all MyISAM tables without any foreign keys, whatsoever, and I've run the same queries in my dev machine and in the production server with the same result, so whatever corruption there might be survived a mysqldump / source cycle, which sounds awfully strange. Any ideas on what could be going wrong, or, even more importantly, how I can fix/work around this? Thanks! Daniel

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• Getting method arguments with Roslyn

  - by Kevin Burton

  I can get a list from the solution of all calls to a particuliar method using the following code: var createCommandList = new List<MethodSymbol>(); INamedTypeSymbol interfaceSymbol = (from p in solution.Projects select p.GetCompilation().GetTypeByMetadataName("BuySeasons.BsiServices.DataResource.IBsiDataConnection")).FirstOrDefault(); foreach (ISymbol symbol in interfaceSymbol.GetMembers("CreateCommand")) { if (symbol.Kind == CommonSymbolKind.Method && symbol is MethodSymbol) { createCommandList.Add(symbol as MethodSymbol); } } foreach (MethodSymbol methodSymbol in createCommandList) { foreach (ReferencedSymbol referenceSymbol in methodSymbol.FindReferences(solution)) { foreach (ReferenceLocation referenceLocation in from l in referenceSymbol.Locations orderby l.Document.FilePath select l) { if (referenceLocation.Location.GetLineSpan(false).StartLinePosition.Line == referenceLocation.Location.GetLineSpan(false).EndLinePosition.Line) { Debug.WriteLine(string.Format("{0} {1} at {2} {3}/{4} - {5}", methodSymbol.Name, "(" + string.Join(",", (from p in methodSymbol.Parameters select p.Type.Name + " " + p.Name).ToArray()) + ")", Path.GetFileName(referenceLocation.Location.GetLineSpan(false).Path), referenceLocation.Location.GetLineSpan(false).StartLinePosition.Line, referenceLocation.Location.GetLineSpan(false).StartLinePosition.Character, referenceLocation.Location.GetLineSpan(false).EndLinePosition.Character)); } else { throw new ApplicationException("Call spans multiple lines"); } } } } But this gives me a list of ReferencedSymbol's. Although this gives me the file and line number that the method is called from I would also like to get the specific arguments that the method is called with. How can I either convert what I have or get the same information with Roslyn? (notice the I first load the solution with the Solution.Load method and then loop through to find out where the method is defined/declared (createCommandList)). Thank you.

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• How can I get the rank of rows relative to total number of rows based on a field?

  - by Arms

  I have a scores table that has two fields: user_id score I'm fetching specific rows that match a list of user_id's. How can I determine a rank for each row relative to the total number of rows, based on score? The rows in the result set are not necessarily sequential (the scores will vary widely from one row to the next). I'm not sure if this matters, but user_id is a unique field. Edit @Greelmo I'm already ordering the rows. If I fetch 15 rows, I don't want the rank to be 1-15. I need it to be the position of that row compared against the entire table by the score property. So if I have 200 rows, one row's rank may be 3 and another may be 179 (these are arbitrary #'s for example only). Edit 2 I'm having some luck with this query, but I actually want to avoid ties SELECT s.score , s.created_at , u.name , u.location , u.icon_id , u.photo , (SELECT COUNT(*) + 1 FROM scores WHERE score > s.score) AS rank FROM scores s LEFT JOIN users u ON u.uID = s.user_id ORDER BY s.score DESC , s.created_at DESC LIMIT 15 If two or more rows have the same score, I want the latest one (or earliest - I don't care) to be ranked higher. I tried modifying the subquery with AND id > s.id but that ended up giving me an unexpected result set and different ties.

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• how to get the checked ID's on submit click

  - by rockers

  $('#PbtnSubmit').click(function(event) { alert("ABC"); $('#PricingEditExceptions input[name=PMchk]').each(function() { if ($("#PricingEditExceptions input:checkbox:checked").length > 0) { var checked = $('#PricingEditExceptions input[name=PMchk]:checked'); alert(checked);.........................this is not working var PMstrIDs = checked.map(function() { return $(this).val(); }).get().join(','); alert(PMstrIDs); $('#1_exceptiontypes').attr('value', exceptiontypes) $('#1_PMstrIDs').attr('value', PMstrIDs); } else { alert("Please select atleast one exception"); event.preventDefault(); } }); when I use this On submit click i am getting first popup window as ABC.. but this.. var checked = $('#PricingEditExceptions input[name=PMchk]:checked'); but this returns Object-object.. in both Firefox and IE8.. but in Firefox alert("PMstrIDs"); return exactly how any checkboxes are check.. but in IE8 it is only returning first Checkbox ID not all..is that any differnce between IE8 and Firefox for this behaviour please can anybody help me out? or can i do this one any other method so that it will work in IE8 browser? thanks

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• Graphical glitches when adding cells and scrolling with UITableView

  - by Daniel I-S

  I am using a UITableView to display the results of a series of calculations. When the user hits 'calculate', I wish to add the latest result to the screen. This is done by adding a new cell to a 'results' section. The UITableViewCell object is added to an array, and then I use the following code to add this new row to what is displayed on the screen: [thisView beginUpdates]; [thisView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation: UITableViewRowAnimationFade]; [thisView endUpdates]; This results in the new cell being displayed. However, I then want to immediately scroll the screen down so that the new cell is the lowermost cell on-screen. I use the following code: [thisView scrollToRowAtIndexPath:newIndexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES]; This almost works great. However, the first time a cell is added and scrolled to, it appears onscreen only briefly before vanishing. The view scrolls down to the correct place, but the cell is not there. Scrolling the view by hand until this invisible new cell's position is offscreen, then back again, causes the cell to appear - after which it behaves normally. This only happens the first time a cell is added; subsequent cells don't have this problem. It also happens regardless of the combination of scrollToRowAtIndexPath and insertRowsAtIndexPath animation settings. There is also a problem where, if new cells are added repeatedly and quickly, the new cells stop 'connecting up'. The lowermost cell in a group is supposed to have rounded corners, and when a new cell is added these turn into square corners so that there is a clean join with the next cell in the group. In this case, however, a cell often does not lose its rounded edges despite not being the last cell anymore. This also gets corrected once the affected area moves offscreen and back. This method of adding and scrolling would be perfect for my application if it weren't for these weird glitches. Any ideas as to what I may be doing wrong?

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• Replacing a word in a text file with a value using python

  - by Jamde Jam

  I have been trying to replace a word in a text file with a value (say 1), but my outfile is blank.I am new to python (its only been a month since I have been learning it). My file is relatively large, but I just want to replace a word with the value 1 for now. Here is a segment of what the file looks like: NAME SECOND_1 ATOM 1 6 0 0 0 # ORB 1 ATOM 2 2 0 12/24 0 # ORB 2 ATOM 3 2 12/24 0 0 # ORB 2 ATOM 4 2 0 0 4/24 # ORB 3 ATOM 5 2 0 0 20/24 # ORB 3 ATOM 6 2 0 0 8/24 # ORB 3 ATOM 7 2 0 0 16/24 # ORB 3 ATOM 8 6 0 0 12/24 # ORB 1 ATOM 9 2 12/24 0 12/24 # ORB 2 ATOM 10 2 0 12/24 12/24 # ORB 2 #1 #2 #3 I want to first replace the word ATOM with the value 1. Next I want to replace #ORB with a space. Here is what I am trying thus far. input = open('SECOND_orbitsJ22.txt','r') output=open('SECOND_orbitsJ22_out.txt','w') for line in input: word=line.split(',') if(word[0]=='ATOM'): word[0]='1' output.write(','.join(word)) Can anyone offer any suggestions or help? Thanks so much.

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• How to check if two records have a self-referencing relation?

  - by Machine

  Consider the following schema with users and their collegues (friends): Users User: columns: user_id: name: user_id as userId type: integer(8) unsigned: 1 primary: true autoincrement: true first_name: name: first_name as firstName type: string(45) notnull: true last_name: name: last_name as lastName type: string(45) notnull: true email: type: string(45) notnull: true unique: true relations: Collegues: class: User local: invitor foreign: invitee refClass: CollegueStatus equal: true onDelete: CASCADE onUpdate: CASCADE Join table: CollegueStatus: columns: invitor: type: integer(8) unsigned: 1 primary: true invitee: type: integer(8) unsigned: 1 primary: true status: type: enum(8) values: [pending, accepted, denied] default: pending notnull: true Now, let's say I two records, one for the user making a HTTP request (the logged in user), and one record for a user he wants to send a message to. I want to check if these users are collegues. Questions: Does Doctrine have any pre-build functionality to check if two records with with self-relations are related? If not, how would you write a method to check this? Where would you put said method? (In the User-class, UserTable-class etc) I could probably do something like this: public function (User $user1, User $user2) { // Ensure we load collegues if $user1 was fetched with DQL that // doesn't load this relation $collegues = $user1->get('Collegues'); $areCollegues = false; foreach($collegues as $collegue) { if($collegue['userId'] === $user2['userId']) { $areCollegues = true; break; } } return $areCollegues; } But this looks a neither efficient nor pretty. I just feel that it should be solved already for self-referencing relations to be nice to use.

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• Optimize a MySQL count each duplicate Query

  - by Onema

  I have the following query That gets the city name, city id, the region name, and a count of duplicate names for that record: SELECT Country_CA.City AS currentCity, Country_CA.CityID, globe_region.region_name, ( SELECT count(Country_CA.City) FROM Country_CA WHERE City LIKE currentCity ) as counter FROM Country_CA LEFT JOIN globe_region ON globe_region.region_id = Country_CA.RegionID AND globe_region.country_code = Country_CA.CountryCode ORDER BY City This example is for Canada, and the cities will be displayed on a dropdown list. There are a few towns in Canada, and in other countries, that have the same names. Therefore I want to know if there is more than one town with the same name region name will be appended to the town name. Region names are found in the globe_region table. Country_CA and globe_region look similar to this (I have changed a few things for visualization purposes) CREATE TABLE IF NOT EXISTS `Country_CA` ( `City` varchar(75) NOT NULL DEFAULT '', `RegionID` varchar(10) NOT NULL DEFAULT '', `CountryCode` varchar(10) NOT NULL DEFAULT '', `CityID` int(11) NOT NULL DEFAULT '0', PRIMARY KEY (`City`,`RegionID`), KEY `CityID` (`CityID`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; AND CREATE TABLE IF NOT EXISTS `globe_region` ( `country_code` char(2) COLLATE utf8_unicode_ci NOT NULL, `region_code` char(2) COLLATE utf8_unicode_ci NOT NULL, `region_name` varchar(50) COLLATE utf8_unicode_ci NOT NULL, PRIMARY KEY (`country_code`,`region_code`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; The query on the top does exactly what I want it to do, but It takes way too long to generate a list for 5000 records. I would like to know if there is a way to optimize the sub-query in order to obtain the same results faster. the results should look like this City CityID region_name counter sheraton 2349269 British Columbia 1 sherbrooke 2349270 Quebec 2 sherbrooke 2349271 Nova Scotia 2 shere 2349273 British Columbia 1 sherridon 2349274 Manitoba 1

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• MySQL Ratings From Two Tables

  - by DirtyBirdNJ

  I am using MySQL and PHP to build a data layer for a flash game. Retrieving lists of levels is pretty easy, but I've hit a roadblock in trying to fetch the level's average rating along with it's pointer information. Here is an example data set: levels Table: level_id | level_name 1 | Some Level 2 | Second Level 3 | Third Level ratings Table: rating_id | level_id | rating_value 1 | 1 | 3 2 | 1 | 4 3 | 1 | 1 4 | 2 | 3 5 | 2 | 4 6 | 2 | 1 7 | 3 | 3 8 | 3 | 4 9 | 3 | 1 I know this requires a join, but I cannot figure out how to get the average rating value based on the level_id when I request a list of levels. This is what I'm trying to do: SELECT levels.level_id, AVG(ratings.level_rating WHERE levels.level_id = ratings.level_id) FROM levels I know my SQL is flawed there, but I can't figure out how to get this concept across. The only thing I can get to work is returning a single average from the entire ratings table, which is not very useful. Ideal Output from the above conceptually valid but syntactically awry query would be: level_id | level_rating 1| 3.34 2| 1.00 3| 4.54 My main issue is I can't figure out how to use the level_id of each response row before the query has been returned. It's like I want to use a placeholder... or an alias... I really don't know and it's very frustrating. The solution I have in place now is an EPIC band-aid and will only cause me problems long term... please help!

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• Why do InterruptedExceptions clear a thread's interrupted status?

  - by Hanno Fietz

  If a thread is interrupted while inside Object.wait() or Thread.join(), it throws an InterruptedException, which resets the thread's interrupted status. I. e., if I have a loop like this inside a Runnable.run(): while (!this._workerThread.isInterrupted()) { // do something try { synchronized (this) { this.wait(this._waitPeriod); } } catch (InterruptedException e) { if (!this._isStopping()) { this._handleFault(e); } } } the thread will continue to run after calling interrupt(). This means I have to explicitly break out of the loop by checking for my own stop flag in the loop condition, rethrow the exception, or add a break. Now, this is not exactly a problem, since this behaviour is well documented and doesn't prevent me from doing anything the way I want. However, I don't seem to understand the concept behind it: Why is a thread not considered interrupted anymore once the exception has been thrown? A similar behaviour also occurs if you get the interrupted status with interrupted() instead of isInterrupted(), then, too, the thread will only appear interrupted once. Am I doing something unusual here? For example, is it more common to catch the InterruptedException outside the loop? (Even though I'm not exactly a beginner, I tagged this "beginner", because it seems like a very basic question to me, looking at it.)

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• What database systems should an startup company consider?

  - by Am

  Right now I'm developing the prototype of a web application that aggregates large number of text entries from a large number of users. This data must be frequently displayed back and often updated. At the moment I store the content inside a MySQL database and use NHibernate ORM layer to interact with the DB. I've got a table defined for users, roles, submissions, tags, notifications and etc. I like this solution because it works well and my code looks nice and sane, but I'm also worried about how MySQL will perform once the size of our database reaches a significant number. I feel that it may struggle performing join operations fast enough. This has made me think about non-relational database system such as MongoDB, CouchDB, Cassandra or Hadoop. Unfortunately I have no experience with either. I've read some good reviews on MongoDB and it looks interesting. I'm happy to spend the time and learn if one turns out to be the way to go. I'd much appreciate any one offering points or issues to consider when going with none relational dbms?

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• Avoid MySQL multi-results from SP with Execute

  - by hhyhbpen

  Hi, i have an SP like BEGIN DECLARE ... CREATE TEMPORARY TABLE tmptbl_found (...); PREPARE find FROM" INSERT INTO tmptbl_found (SELECT userid FROM ( SELECT userid FROM Soul WHERE .?.?. ORDER BY .?.?. ) AS left_tbl LEFT JOIN Contact ON userid = Contact.userid WHERE Contact.userid IS NULL LIMIT ?) "; DECLARE iter CURSOR FOR SELECT userid, ... FROM Soul ...; ... l:LOOP FETCH iter INTO u_id, ...; ... EXECUTE find USING ...,. . .,u_id,...; ... END LOOP; ... END// and it gives multi-results. Besides it's inconvenient, if i get all this multi-results (which i really don't need at all), about 5 (limit's param) for each of the hundreds of thousands of records in Soul, i'm afraid it will take all my memory (and all in vain). Also, i noticed, if i do prepare from an empty string, it still has multi-results... At least how to get rid of them in the execute statement? And i would like to have a recipe to avoid ANY output from SP, for any possible statement (i also have a lot of "update ..."s and "select ... into "s inside, if they can produce multi's). Tnx for any help...

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• Refactoring a leaf class to a base class, and keeping it also a interface implementation

  - by elcuco

  I am trying to refactor a working code. The code basically derives an interface class into a working implementation, and I want to use this implementation outside the original project as a standalone class. However, I do not want to create a fork, and I want the original project to be able to take out their implementation, and use mine. The problem is that the hierarchy structure is very different and I am not sure if this would work. I also cannot use the original base class in my project, since in reality it's quite entangled in the project (too many classes, includes) and I need to take care of only a subdomain of the problems the original project is. I wrote this code to test an idea how to implement this, and while it's working, I am not sure I like it: #include <iostream> // Original code is: // IBase -> Derived1 // I need to refactor Derive2 to be both indipendet class // and programmers should also be able to use the interface class // Derived2 -> MyClass + IBase // MyClass class IBase { public: virtual void printMsg() = 0; }; /////////////////////////////////////////////////// class Derived1 : public IBase { public: virtual void printMsg(){ std::cout << "Hello from Derived 1" << std::endl; } }; ////////////////////////////////////////////////// class MyClass { public: virtual void printMsg(){ std::cout << "Hello from MyClass" << std::endl; } }; class Derived2: public IBase, public MyClass{ virtual void printMsg(){ MyClass::printMsg(); } }; class Derived3: public MyClass, public IBase{ virtual void printMsg(){ MyClass::printMsg(); } }; int main() { IBase *o1 = new Derived1(); IBase *o2 = new Derived2(); IBase *o3 = new Derived3(); MyClass *o4 = new MyClass(); o1->printMsg(); o2->printMsg(); o3->printMsg(); o4->printMsg(); return 0; } The output is working as expected (tested using gcc and clang, 2 different C++ implementations so I think I am safe here): [elcuco@pinky ~/src/googlecode/qtedit4/tools/qtsourceview/qate/tests] ./test1 Hello from Derived 1 Hello from MyClass Hello from MyClass Hello from MyClass [elcuco@pinky ~/src/googlecode/qtedit4/tools/qtsourceview/qate/tests] ./test1.clang Hello from Derived 1 Hello from MyClass Hello from MyClass Hello from MyClass The question is My original code was: class Derived3: public MyClass, public IBase{ virtual void IBase::printMsg(){ MyClass::printMsg(); } }; Which is what I want to express, but this does not compile. I must admit I do not fully understand why this code work, as I expect that the new method Derived3::printMsg() will be an implementation of MyClass::printMsg() and not IBase::printMsg() (even tough this is what I do want). How does the compiler chooses which method to re-implement, when two "sister classes" have the same virtual function name? If anyone has a better way of implementing this, I would like to know as well :)

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• javaScript .splice() not working on correctly

  - by adardesign

  I am setting a cookie for each navigation container that is clicked on. It sets an array that is joined and set the cookie value. if its clicked again then its removed from the array. It somehow buggy. It only splices after clicking on other elements. and then it behaves weird. Thanks much. var navLinkToOpen; var setNavCookie = function(value){ var isSet = false; var checkCookies = checkNavCookie() setCookieHelper = checkCookies? checkCookies.split(","): []; console.log("value passed", value) for(i in setCookieHelper){ if(value == setCookieHelper[i]){ setCookieHelper.splice(value,1); isSet = true; } } if(!isSet){ setCookieHelper.push(value) } setCookieHelper.join(",") document.cookie = "navLinkToOpen"+"="+setCookieHelper; } var checkNavCookie = function(){ var allCookies = document.cookie.split( ';' ); for (i = 0; i < allCookies.length; i++ ){ temp = allCookies[i].split("=") if(temp[0].match("navLinkToOpen")){ var getValue = temp[1] } } return getValue || false } $(document).ready(function() { $("#LeftNav li").has("b").addClass("navHeader").not(":first").siblings("li").hide() $(".navHeader").click(function(){ $(this).toggleClass("collapsed").nextUntil("li:has('b')").slideToggle(300); setNavCookie($('.navHeader').index($(this))) return false }) console.log("init",document.cookie) var testCookies = checkNavCookie(); if(testCookies){ finalArrayValue = testCookies.split(",") for(i in finalArrayValue){ $(".navHeader").eq(finalArrayValue[i]).toggleClass("collapsed").nextUntil(".navHeader").slideToggle (0); } } });

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• How to map a Dictionary<string, string> spanning several tables

  - by Kim Johansson

  I have four tables: CREATE TABLE [Languages] ( [Id] INTEGER IDENTITY(1,1) NOT NULL, [Code] NVARCHAR(10) NOT NULL, PRIMARY KEY ([Id]), UNIQUE INDEX ([Code]) ); CREATE TABLE [Words] ( [Id] INTEGER IDENTITY(1,1) NOT NULL, PRIMARY KEY ([Id]) ); CREATE TABLE [WordTranslations] ( [Id] INTEGER IDENTITY(1,1) NOT NULL, [Value] NVARCHAR(100) NOT NULL, [Word] INTEGER NOT NULL, [Language] INTEGER NOT NULL, PRIMARY KEY ([Id]), FOREIGN KEY ([Word]) REFERENCES [Words] ([Id]), FOREIGN KEY ([Language]) REFERENCES [Languages] ([Id]) ); CREATE TABLE [Categories] ( [Id] INTEGER IDENTITY(1,1) NOT NULL, [Word] INTEGER NOT NULL, PRIMARY KEY ([Id]), FOREIGN KEY ([Word]) REFERENCES [Words] ([Id]) ); So you get the name of a Category via the Word - WordTranslation - Language relations. Like this: SELECT TOP 1 wt.Value FROM [Categories] AS c LEFT JOIN [WordTranslations] AS wt ON c.Word = wt.Word WHERE wt.Language = ( SELECT TOP 1 l.Id FROM [Languages] WHERE l.[Code] = N'en-US' ) AND c.Id = 1; That would return the en-US translation of the Category with Id = 1. My question is how to map this using the following class: public class Category { public virtual int Id { get; set; } public virtual IDictionary<string, string> Translations { get; set; } } Getting the same as the SQL query above would be: Category category = session.Get<Category>(1); string name = category.Translations["en-US"]; And "name" would now contain the Category's name in en-US. Category is mapped against the Categories table. How would you do this and is it even possible?

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• How can I optimize the SELECT statement running on an Oracle database?

  - by Elvis Lou

  I have a SELECT statement in ORACLE: SELECT COUNT(DISTINCT ds1.endpoint_msisdn) multiple30, dss1.service, dss1.endpoint_provisioning_id, dss1.company_scope, Nvl(x.subscription_status, dss1.subscription_status) subscription_status FROM daily_summary ds1 join daily_summary ds2 ON ds1.endpoint_msisdn = ds2.endpoint_msisdn, daily_summary_static dss1, daily_summary_static dss2, (SELECT NULL subscription_status FROM dual UNION ALL SELECT -2 subscription_status FROM dual) x WHERE ds1.summary_ts >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND ds1.summary_ts <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss1.last_active >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND dss1.last_active <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss2.last_active >= To_date('10-04-2012', 'dd-mm-yyyy') - 30 AND dss2.last_active <= To_date('10-04-2012', 'dd-mm-yyyy') AND dss1.service <> dss2.service AND ( dss1.company_scope = 2 OR dss1.company_scope = 5 ) AND ( dss2.company_scope = 2 OR dss2.company_scope = 5 ) AND dss1.company_scope = dss2.company_scope AND ds1.endpoint_noc_id = dss1.endpoint_noc_id AND ds1.endpoint_host_id = dss1.endpoint_host_id AND ds1.endpoint_instance_id = dss1.endpoint_instance_id AND ds2.endpoint_noc_id = dss2.endpoint_noc_id AND ds2.endpoint_host_id = dss2.endpoint_host_id AND ds2.endpoint_instance_id = dss2.endpoint_instance_id AND dss1.endpoint_provisioning_id = dss2.endpoint_provisioning_id AND Least(1, ds1.total_actions) = 1 AND Least(1, ds2.total_actions) = 1 GROUP BY dss1.service, dss1.endpoint_provisioning_id, dss1.company_scope, Nvl(x.subscription_status, dss1.subscription_status); This query took about 26 minutes to return in my environment, but if I remove the section: dss1.last_active >= to_date('10-04-2012','dd-mm-yyyy') - 30 AND dss1.last_active <= to_date('10-04-2012','dd-mm-yyyy') AND dss2.last_active >= to_date('10-04-2012','dd-mm-yyyy') - 30 AND dss2.last_active <= to_date('10-04-2012','dd-mm-yyyy') AND it only took 20 seconds to run. We have index on the column last_active, I don't know why the section slow down the performance so much? any ideas?

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