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SQL GUID Vs Integer

- by Dal

Hi I have recently started a new job and noticed that all the SQL tables use the GUID data type for the primary key. In my previous job we used integers (Auto-Increment) for the primary key and it was a lot more easier to work with in my opinion. For example, say you had two related tables; Product and ProductType - I could easily cross check the 'ProductTypeID' column of both tables for a particular row to quickly map the data in my head because its easy to store the number (2,4,45 etc) as opposed to (E75B92A3-3299-4407-A913-C5CA196B3CAB). The extra frustration comes from me wanting to understand how the tables are related, sadly there is no Database diagram :( A lot of people say that GUID's are better because you can define the unique identifer in your C# code for example using NewID() without requiring SQL SERVER to do it - this also allows you to know provisionally what the ID will be.... but I've seen that it is possible to still retrieve the 'next auto-incremented integer' too. A DBA contractor reported that our queries could be up to 30% faster if we used the Integer type instead of GUIDS... Why does the GUID data type exist, what advantages does it really provide?... Even if its a choice by some professional there must be some good reasons as to why its implemented?

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GET Trello JSON to put in a string var

- by Verber

I'm trying to get the JSON that a TRELLO API Url returns and put it into a string. On my own private board I am getting "401 Unauthorized". But the Trello Api doesn't seem to give any way to authorize a user through the URL. If I try a public board I get "XMLHttpRequest cannot load https://api.trello.com/1/board/4d5ea62fd76aa1136000000c?key=68d02bf40d2ad57dd9eb418eb15f9564. Request header field X-Requested-With is not allowed by Access-Control-Allow-Headers." This is my code: <body> <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"> </script> <script> var list = $.getJSON(" https://api.trello.com/1/board/4d5ea62fd76aa1136000000c? key=68d02bf40d2ad57dd9eb418eb15f9564"); document.getElementById('print').innerHTML = list; </script> <div id="print"> </div> </body>

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MAD method compression function

- by Jacques

I ran across the question below in an old exam. My answers just feels a bit short and inadequate. Any extra ideas I can look into or reasons I have overlooked would be great. Thanx Consider the MAD method compression function, mapping an object with hash code i to element [(3i + 7)mod9027]mod6000 of the 6000-element bucket array. Explain why this is a poor choice of compression function, and how it could be improved. I basically just say that the function could be improved by changing the value for p (or 9027) to an prime number and choosing an other constant for a (or 3) could also help.

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Symfony fk issue on insertion

- by Daniel Hertz

Hi, I posted a similar problem but it could not be resolved. I create a relational database of users and groups but for some reason I cannot insert test data with fixtures properly. Here is a sample of the schema: User: actAs: { Timestampable: ~ } columns: name: { type: string(255), notnull: true } email: { type: string(255), notnull: true, unique: true } nickname: { type: string(255), unique: true } password: { type: string(300), notnull: true } image: { type: string(255) } Group: actAs: { Timestampable: ~ } columns: name: { type: string(500), notnull: true } image: { type: string(255) } type: { type: string(255), notnull: true } created_by_id: { type: integer } relations: User: { onDelete: SET NULL, class: User, local: created_by_id, foreign: id, foreignAlias: groups_created } FanOf: actAs: { Timestampable: ~ } columns: user_id: { type: integer, primary: true } group_id: { type: integer, primary: true } relations: User: { onDelete: CASCADE, local: user_id, foreign: id, foreignAlias: fanhood } Group: { onDelete: CASCADE, local: group_id, foreign: id, foreignAlias: fanhood } And this is the data i try to input: User: user1: name: Danny email: [email protected] nickname: danny password: f05050400c5e586fa6629ef497be Group: group1: name: Mets type: sports FanOf: fans1: user_id: user1 group_id: group1 I keep getting this error: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`krowdd`.`fan_of`, CONSTRAINT `fan_of_user_id_user_id` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`) ON DELETE CASCADE) The users and groups are clearly being created before the "fanhood" is so why am I getting this error?? Thanks!

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Problems when I try to see databases in SQLite

- by Sabau Andreea

I created in code a database and two tables: static final String dbName="graficeCirculatie"; static final String ruteTable="Rute"; static final String colRuteId="RutaID"; static final String colRuta="Ruta"; static final String statiaTable="Statia"; static final String colStatiaID="StatiaID"; static final String colIdRuta="IdRuta"; static final String colStatia="Statia"; public DatabaseHelper(Context context) { super(context, dbName, null,33); } public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL("CREATE TABLE " + statiaTable + " (" + colStatiaID + " INTEGER PRIMARY KEY , " + colIdRuta + " INTEGER, " + colStatia + " TEXT)"); db.execSQL("CREATE TABLE " + ruteTable + "(" + colRuteId + " INTEGER PRIMARY KEY AUTOINCREMENT, " + colRuta + " TEXT);"); InsertDepts(db); } void InsertDepts(SQLiteDatabase db) { ContentValues cv = new ContentValues(); cv.put(colRuteId, 1); cv.put(colRuta, "Expres8"); db.insert(ruteTable, colRuteId, cv); cv.put(colRuteId, 2); cv.put(colRuta, "Expres2"); db.insert(ruteTable, colRuteId, cv); cv.put(colRuteId, 3); cv.put(colRuta, "Expres3"); db.insert(ruteTable, colRuteId, cv); } Now I want to see tables inputs from command line. I try in this way: C:\Program Files\Android\android-sdk\tools sqlite3 SQLite version 3.7.4 Enter ".help" for instructions Enter SQL statements terminated with a ";" sqlite sqlite3 graficeCirculatie ... select * from ruteTable; And I got an error: Error: near "squlite3": syntax error. Can someone help me?

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Internet Explorer cannot 'fully' load ActiveX Control

- by K Browne

Context I am migrating an installer for an ActiveX control from Per-Machine to Per-User. I did this by programming the installer write to HKCU\Software\Classes instead of HKLM\Software\Classes. Problem On my machine (Windows 7 with UAC Enabled), the ActiveX control successfully loads. On the other windows 7 test machines (one with UAC enabled, one with UAC disabled), the control 'partially' loads. What is Partially? When a user visits a page with the ActiveX control, Internet Explorer displays a warning message in a yellow bar on the top of the window. If you click the 'Run add-on' button in the bar, the control becomes visible and begins to run, but Javascript code that tries to access properties of the control return the error: Library not registered. Differences between machines On the dev machine reads from HKCR\CLSID\<GUID> succeed while on the test machines these reads fail. Reads from HKCU succeed on both dev and test machines. Reads from HKLM fail on both test and dev machines. (I collected reads using Sysinternals Process Monitor) Strangely, the keys that Internet Explorer fails to read are clearly visible if I use regedit to view HKCR\CLSID\<GUID> on the test machines. Question What can I do to get the per-user control to load on the test machines? What could cause this difference between the dev machine and the test machines? Why can I see the key in HKCR with RegEdit but Internet Explorer cannot see the key? Any help is appreciated. Thank you.

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Get children count via HQL

- by Thomas Lötzer

Hi, I have a one-to-many mapping between a parent entity and child entities. Now I need to find the number of children associated with each parent for a list of parents. I am trying to do this with HQL but I am not sure how I can get the list of parents in there. Also, I don't know how I can return the entity itself and not just its ID. My current HQL query is: select new map(parent.id as parentId, count(*) as childCount) from Parent parent left join parent.children children group by parent.id but this only returns the ID and does not filter on specific parents. EDIT Based on Pascal's answer I have modified the query to select new map(parent as parent, count(elements(parent.children)) as childCount) from Parent parent group by parent That does work, but is prohibitively slow: 30 seconds instead of 400 ms on the same database.

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nHibernate session - Using repository pattern in Web, windows, wcf etc...

- by alex

I recently posted a question which was answered by Bryan Watts, regarding generic repository for nHibernate. I'm trying to design my data access to allow various facets - from ASP.net, WCF and Windows Forms / Windows services. I'm a bit confused re: session management etc.. How would I handle this? I've been checking out code such as: http://membranecms.googlecode.com/svn/ and questions such as: http://stackoverflow.com/questions/1207833/nhibernate-linq-session-management But what do i do if i don't just do things in a web based environment..? Do i need to create different repositories for each client? Or do i pass in the ISession into the (for example) UserRepository constructor..? ... as a side note I'm using nHibernate.Linq Also using fluent nHibernate to config my mapping

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Keyboard input: how to separate keycodes received from user

- by Iulian Serbanoiu

Hello, I am writing an application involving user input from the keyboard. For doing it I use this way of reading the input: #include <stdio.h> #include <termios.h> #include <unistd.h> int mygetch( ) { struct termios oldt, newt; int ch; tcgetattr( STDIN_FILENO, &oldt ); newt = oldt; newt.c_lflag &= ~( ICANON | ECHO ); tcsetattr( STDIN_FILENO, TCSANOW, &newt ); ch = getchar(); tcsetattr( STDIN_FILENO, TCSANOW, &oldt ); return ch; } int main(void) { int c; do{ c = mygetch(); printf("%d\n",c); }while(c!='q'); return 0; } Everyting works fine for letters digits,tabs but when hiting DEL, LEFT, CTRL+LEFT, F8 (and others) I receive not one but 3,4,5 or even 6 characters. The question is: Is is possible to make a separation of these characters (to actually know that I only hit one key or key combination). What I would like is to have a function to return a single integer value for any type of input (letter, digit, F1-F12, DEl, PGUP, PGDOWN, CTRL+A, CTRL+ALT+A, ALT+LEFT, etc). Is this possible? I'm interested in an idea to to this, the language doesn't matter much, though I'd prefer perl or c. Thanks, Iulian

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How to find NSOutlineView row index when using NSTreeController

- by velocityb0y

I'm using an NSTreeController to manage nodes for an NSOutlineView. When the user adds a new item, I create a new object and insert it: EntityViewEntityNode *newNode = [EntityViewEntityNode nodeWithName:@"New entity" entity:newObject]; // Insert at end of group // NSIndexPath *insertAt = [pathOfGroupNode indexPathByAddingIndex:[selected.children count]]; [entityCollectionTreeController insertObject:newNode atArrangedObjectIndexPath:insertAt]; Now I'd like to open the table column for edit so the user can name the new item. This seems logical: NSInteger row = [entityCollectionOutlineView rowForItem:newNode]; [entityCollectionOutlineView editColumn:0 row:row withEvent:nil select:YES]; However, row is always -1 indicating the object isn't found. Poking around reveals that the tree controller is not actually putting my objects directly in the tree, but is wrapping them in a node object of its own. Anyone have insight into how I would go about getting a row index relative to the outline view, so I can do this (without, hopefully, enumerating everything in the outline view and figuring out the mapping back to my node?)

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storing/retrieving data for graph with long continuous stretches

- by james

i have a large 2-dimensional data set which i would like to graph. the graph is displayed in a browser and the data is retrieved via ajax. long stretches of this graph will be continuous - e.g., for x=0 through x=1000, y=9, then for x=1001 through x=1100, y=80, etc. the approach i'm considering is to send (from the server) and store (in the browser) only the points where the data changes. so for the example above, i would say data[0] = 9, then data[1001] = 80. then given x=999 for example, retrieving data[999] would actually look up data[0]. the problem that arises is finding a dictionary-like data structure which behaves like this. the approach i'm considering is to store the data in a traditional dictionary object, then also maintain a sorted array of key for that object. when given x=999, it would look at the mid-point of this array, determine whether the nearest lower key is left or right of that midpoint, then repeat with the correct subsection, etc.. does anyone have thoughts on this problem/approach?

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Windows Azure: asp.net <appsetting> for ChatHttpHandler not found

- by veda

I have a problem in setting the chartHttpHandler in web.config for windows azure Initially I added a chartHttpHandler on my web.config file <remove name="ChartImageHandler"/> <add name="ChartImageHandler" preCondition="integratedMode" verb="GET,HEAD" path="ChartImg.axd" type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, System.Web.DataVisualization, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/> under system.webServer section Then I got an error stating Invalid temp directory in chart handler configuration [c:\TempImageFiles\]. Then I found that I should change in From <add key="ChartImageHandler" value="storage=file;timeout=20;dir=c:\TempImageFiles\;" /> To <add key="ChartImageHandler" value="storage=file;timeout=20;" /> I am not able to find this section in my web.config file. So I tried to add it under section but it gave me error that it is an invalid child Likewise, I tried adding it under section, it too gave the same error... So, I added sepeartely, Then I am not able to see anything.. The webpage is just blank... What should I have to do.. Can anyone tell me "how to solve it"

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RESTful Question/Answer design?

- by Kirschstein

This is a toy project I'm working on at the moment. My app contains questions with multiple choice answers. The question url is in the following format, with GET & POST mapping to different actions on the questions controller. GET: url.com/questions/:category/:difficulty => 'ask' POST: url.com/questions/:category/:difficulty => 'answer' I'm wondering if it's worth redesigning this into a RESTful style. I know I'd need to introduce answers as a resource, but I'm struggling to think of a url that would look natural for answering that question. Would a redesign be worthwhile? How would you go about structuring the urls?

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Flex Force Decimal

- by babyangel86

Hi, I'm looking for a regex or a way to format the NumberValidator so that only decimal places are allowed. The domain="real" allows you to put integer values, but I need to force the user to but in 2.0 if they want an integer. This is because they pass through a Castor mapping file, it complains if it gets an integer when it expects a decimal. I dont want to restrict the number of decimal places, just insist that there must be a point, and a number after it. Any help would be much appreciated.

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How do I create and use a junction table in Rails?

- by Thierry Lam

I have the following data: A post called Hello has categories greet Another post called Hola has categories greet, international My schema is: create_table "posts", :force => true do |t| t.string "name" t.datetime "created_at" t.datetime "updated_at" end create_table "categories", :force => true do |t| t.string "name" t.datetime "created_at" t.datetime "updated_at" end create_table "posts_categories", :force => true do |t| t.integer "post_id" t.integer "category_id" t.datetime "created_at" t.datetime "updated_at" end After reading the Rails guide, the most suitable relationship for the above seems to be: class Post < ActiveRecord::Base has_and_belongs_to_many :categories end class Category < ActiveRecord::Base has_and_belongs_to_many :posts end My junction table also seems to have a primary key. I think I need to get rid of it. What's the initial migration command to generate a junction table in Rails? What's the best course of action, should I drop posts_categories and re-create it or just drop the primary key column? Does the junction table have a corresponding model? I have used scaffold to generate the junction table code, should I get rid of the extra code? Assuming all the above has been fixed and is working properly, how do I query all posts and display them along with their named categories in the view. For example: Post #1 - hello, categories: greet Post #2 - hola, categories: greet, international

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How does the overall view hierarchy change when using UIKit view manipulations?

- by executor21

I've been trying to figure out what happens in the view hierarchy when methods like pushViewController:animated, presentModalViewController:animated, and tab switches in UITabBarViewController are used, as well as UIAlertView and UIActionSheet. (Side note: I'm doing this because I need to know whether a specific UIView of my creation is visible on screen when I do not know anything about how it or its superview may have been added to the view hierarchy. If someone knows a good way to determine this, I'd welcome the knowledge.) To figure it out, I've been logging out the hierarchy of [[UIApplication sharedApplication] keyWindow] subviews in different circumstances. Is the following correct: When a new viewController is pushed onto the stack of a UINavigationController, the old viewController's view is no longer in the view hierarchy. That is, only the top view controller's view is a subview of UINavigationController's view (according to logs, it's actually several private classes such as UILayoutContainerView). Are the views of view controllers below the top controller of the stack actually removed from the window? A very similar thing happens when a new viewController is presented via presentModalViewController:animated. The new viewController's view is the only subview of the kew window. Is this correct? The easiest thing to understand: a UIAlertView creates its own window and makes it key. The strangest thing I encountered: a UIActionSheet is shown via showInView: method, the actionSheet isn't in the view hierarchy at all. It's not a subview of the view passed as an argument to showInView:, it isn't added as a subview of the key window, and it doesn't create its own window. How does it appear, then? I haven't tried this yet, so I'd like to know what happens in the keyWindow hierarchy when tabs in a UITabBarController are switched. Is the view of the selected UIViewController moved to the top, or does it work like with pushViewController:animated and presentModalViewController:animated, where only the displayed view is in the window hierarchy?

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SQL Server: Granting db_datawriter on all databases

- by Michael J Swart

I want to manage permissions and access to a SQL Server database server on a development machine. I've created a local windows group (called DBReaderGroup) and assigned various people to it. The group was created as a SQL Server login successfully: create login [MYMACHINE\DBReaderGroup] from windows My goal is to grant this group read/write access to all databases (which are constantly being added and dropped). Is it possible to configure the right settings so that SQL Server manages this? My biggest challenge is that each time a db is created, I have to update the "User Mapping" settings for this group on the new database. Am I missing something simple?

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Restkit Serializing a Boolean from NSNumber

- by angelokh

One of managed objects has one attribute 'isMember' represented by NSNumber type. When serialize to Json post body by RestKit, it always give 0/1 instead of YES/NO or true/false. When mapping from json result to objects, RestKit is able to successfully turn YES/NO to NSNumber. What is the way to force serialize the boolean attribute to YES/NO or true/false? Serialize: 0 -> 0, 1 -> 1 Deserialize : YES/true -> 1, NO/false -> 0

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retrieve my wall post in my native i phone application

- by hardik

hello all i want to retrieve my all the wall post that i have posted until now i am using this fql query from my native iphone application in order to fetch it but i think i am maiking some mistake please guide me how could i do that the following is my fql query to get wall post - (void)session:(FBSession*)session didLogin:(FBUID)uid { NSString *fql = [NSString stringWithFormat:@"SELECT comments, likes FROM stream WHERE post_id=100000182297319"]; NSLog(@"session key is %@",_session.sessionKey); NSLog(@"from global key is %@",[twitfacedemoAppDelegate getfacebookkey]); NSDictionary* params = [NSDictionary dictionaryWithObject:fql forKey:@"query"]; [[FBRequest requestWithDelegate:self] call:@"facebook.fql.query" params:params]; this is my other delgate method to get the wall post but this code is not working - (void)request:(FBRequest*)request didLoad:(id)result { @try { NSLog(@"result is %@",result); if(result==nil) { UIAlertView *a=[[UIAlertView alloc]initWithTitle:@"Can't login" message:@"You cant login here." delegate:nil cancelButtonTitle:@"ok" otherButtonTitles:nil]; [a show]; [a release]; } else { NSArray* users = result; NSDictionary* user = [users objectAtIndex:0]; NSString* name = [[NSString alloc]initWithString:[user objectForKey:@"name"]]; NSLog(@"name is %@",name); _label.text = [NSString stringWithFormat:@"Logged in as %@", name]; NSString *globalfacebookname; globalfacebookname=[[NSString alloc]initWithString:name]; NSLog(@"value is %@",globalfacebookname); NSString *fid=[user objectForKey:@"uid"]; NSLog(@"FACEBOOK ID WITH STRING DATATYP %@",fid); [twitfacedemoAppDelegate fetchfacebookid:fid]; } } @catch (NSException * e) { NSLog(@"Problem in dialog didFailWithError:%@",e); } } please guide me how could i retrieve my all the post from facebook to my native iphone application through fql query thanks in advance

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Can't bind string containing @ char with mysqli_stmt_bind_param

- by Tirithen

I have a problem with my database class. I have a method that takes one prepared statement and any number of parameters, binds them to the statement, executes the statement and formats the result into a multidimentional array. Everthing works fine until I try to include an email adress in one of the parameters. The email contains an @ character and that one seems to break everything. When I supply with parameters: $types = "ss" and $parameters = array("[email protected]", "testtest") I get the error: Warning: Parameter 3 to mysqli_stmt_bind_param() expected to be a reference, value given in ...db/Database.class.php on line 63 Here is the method: private function bindAndExecutePreparedStatement(&$statement, $parameters, $types) { if(!empty($parameters)) { call_user_func_array('mysqli_stmt_bind_param', array_merge(array($statement, $types), &$parameters)); /*foreach($parameters as $key => $value) { mysqli_stmt_bind_param($statement, 's', $value); }*/ } $result = array(); $statement->execute() or debugLog("Database error: ".$statement->error); $rows = array(); if($this->stmt_bind_assoc($statement, $row)) { while($statement->fetch()) { $copied_row = array(); foreach($row as $key => $value) { if($value !== null && mb_substr($value, 0, 1, "UTF-8") == NESTED) { // If value has a nested result inside $value = mb_substr($value, 1, mb_strlen($value, "UTF-8") - 1, "UTF-8"); $value = $this->parse_nested_result_value($value); } $copied_row[$ke<y] = $value; } $rows[] = $copied_row; } } // Generate result $result['rows'] = $rows; $result['insert_id'] = $statement->insert_id; $result['affected_rows'] = $statement->affected_rows; $result['error'] = $statement->error; return $result; } I have gotten one suggestion that: the array_merge is casting parameter to string in the merge change it to &$parameters so it remains a reference So I tried that (3rd line of the method), but it did not do any difference. How should I do? Is there a better way to do this without call_user_func_array?

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What is the iPad user agent?

- by Yoric

Now that the iPad craze is officially open, it's time to think websites also for the iPad. From what I gather, the iPad is using iPhone OS, but with a different screen resolution from the iPhone/iPod touch. So suddenly, the assumption that iPhone OS = iPhone screen resolution becomes false. Sounds like many sites may have to revise their user-agent - css mapping. So, can anyone with access to the iPad or the iPad SDK give us the user-agent string? Thanks in advance.

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ASP.NET MVC Routes

- by MVCDummy09

Can I see one example that would make this piece of code compile? public IEnumerable<RouteBase> Routes { get { return new List<Route>() { new Route(...) } } } What would you do if RouteCollection.MapRoute() didn't exist? I'm trying to put my Controller in charge of mapping routes, not Global.asax.cs. public IEnumerable<RouteBase> Routes is a member of my Controller. If the Controller is responsible for a Route, it's a bad idea to decouple the Route by using routes.MapRoute() in Global.asax.cs.

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Poor execution plans when using a filter and CONTAINSTABLE in a query

- by Paul McLoughlin

We have an interesting problem that I was hoping someone could help to shed some light on. At a high level the problem is as below: The following query executes quickly (1 second): SELECT SA.* FROM cg.SEARCHSERVER_ACTYS AS SA JOIN CONTAINSTABLE(CG.SEARCHSERVER_ACTYS, NOTE, 'reports') AS T1 ON T1.[Key]=SA.UNIQUE_ID but if we add a filter to the query, then it takes approximately 2 minutes to return: SELECT SA.* FROM cg.SEARCHSERVER_ACTYS AS SA JOIN CONTAINSTABLE(CG.SEARCHSERVER_ACTYS, NOTE, 'reports') AS T1 ON T1.[Key]=SA.UNIQUE_ID WHERE SA.CHG_DATE'19 Feb 2010' Looking at the execution plan for the two queries, I can see that in the second case there are two places where there are huge differences between the actual and estimated number of rows, these being: 1) For the FulltextMatch table valued function where the estimate is approx 22,000 rows and the actual is 29 million rows (which are then filtered down to 1670 rows before the join) and 2) For the index seek on the full text index, where the estimate is 1 row and the actual is 13,000 rows As a result of the estimates, the optimiser is choosing to use a nested loops join (since it assumes a small number of rows) hence the plan is inefficient. We can work around the problem by either (a) parameterising the query and adding an OPTION (OPTIMIZE FOR UNKNOWN) to the query or (b) by forcing a HASH JOIN to be used. In both of these cases the query returns in sub 1 second and the estimates appear reasonable. My question really is 'why are the estimates being used in the poorly performing case so wildly inaccurate and what can be done to improve them'? Statistics are up to date on the indexes on the indexed view being used here. Any help greatly appreciated.

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Bidirectional one-to-many associations with indexed collections in NHibernate

- by Jørn Schou-Rode

Last summer, I asked a question regarding how to add new object to an IList mapped as a one-to-many with NHibernate. One of the answers let me to this paragraph in the documentation: Please note that NHibernate does not support bidirectional one-to-many associations with an indexed collection (list, map or array) as the "many" end, you have to use a set or bag mapping. While I am pretty sure I understand what this paragraph says, I have no idea why or how to work around this limitation. As I am now again working with a model that seems to require a "bidirectional one-to-many association with an index collection", I figured the time was right for follow-up questions: Why does NHibernate have this limitation on associations? It is my impression that the guys behind NHibernate are quite clever, so I assume there is a pretty good reason. What are the common workarounds for this shortcoming? Making the collection a non-indexed bag and adding an explicit Position property to the child class? Any better solutions?

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JPA : Inheritance - Discriminator value not taken into account in generated SQL

- by Julien

I try to use this mapping : @Entity @Table(name="ecc.\"RATE\"") @Inheritance(strategy=InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name="DISCRIMINATOR", discriminatorType= DiscriminatorType.STRING) public abstract class Rate extends GenericBusinessObject { ... } @Entity @DiscriminatorValue("E") public class EntranceRate extends Rate { @ManyToOne @JoinColumn(name = "\"RATES_GRID_ID\"") protected RatesGrid ratesGrid; ... } @Entity @Table(name="ecc.\"RATES_GRID\"") public class RatesGrid extends GenericBusinessObject { /** */ @OneToMany(mappedBy = "ratesGrid", targetEntity = EntranceRate.class, fetch=FetchType.LAZY) private List<EntranceRate> entranceRates; } When I try to access my entranceRates list from a ratesGrid object, I get this error : Object with id: 151 was not of the specified subclass: com.ecc.bo.rate.EntranceRate (loaded object was of wrong class class com.ecc.bo.rate.AnnualRate) Looking at the sql generated, I found no trace of "discriminator=" in the where clause. What am I doing wrong ? I use a PostGreSQL database and a Hibernate as JPA provider.

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