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  • How to have multiple tables with multiple joins

    - by williamsdb
    I have three tables that I need to join together and get a combination of results. I have tried using left/right joins but they don't give the desired results. For example: Table 1 - STAFF id name 1 John 2 Fred Table 2 - STAFFMOBILERIGHTS id staffid mobilerightsid rights --this table is empty-- Table 3 - MOBILERIGHTS id rightname 1 Login 2 View and what I need is this as the result... id name id staffid mobilerightsid rights id rightname 1 John null null null null 1 login 1 John null null null null 2 View 2 Fred null null null null 1 login 2 Fred null null null null 2 View I have tried the following : SELECT * FROM STAFFMOBILERIGHTS SMR RIGHT JOIN STAFF STA ON STA.STAFFID = SMR.STAFFID RIGHT JOIN MOBILERIGHTS MRI ON MRI.ID = SMR.MOBILERIGHTSID But this only returns two rows as follows: id name id staffid mobilerightsid rights id rightname null null null null null null 1 login null null null null null null 2 View Can what I am trying to achieve be done and if so how? Thanks

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  • using "IS" is better or checking for "NOT NULL"

    - by BDotA
    In C#.NET language: This style of coding is recommended or the one below it? if (sheet.Models.Data is GroupDataModel) { GroupDataModel gdm = (GroupDataModel)sheet.Models.Data; Group group = gdm.GetGroup(sheet.ActiveCell.Row.Index); if (group!=null && controller != null) { controller.CheckApplicationState(); } } or this one: var gdm = sheet.Models.Data as GroupDataModel; if (gdm != null) { Group group = gdm.GetGroup(sheet.ActiveCell.Row.Index); if (@group!=null && controller != null) { controller.CheckApplicationState(); } }

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  • Is it a bad idea if equals(null) throws NullPointerException instead?

    - by polygenelubricants
    The contract of equals with regards to null, is as follows: For any non-null reference value x, x.equals(null) should return false. This is rather peculiar, because if o1 != null and o2 == null, then we have: o1.equals(o2) // returns false o2.equals(o1) // throws NullPointerException The fact that o2.equals(o1) throws NullPointerException is a good thing, because it alerts us of programmer error. And yet, that error would not be catched if for various reasons we just switched it around to o1.equals(o2), which would just "silently fail" instead. So the questions are: Why is it a good idea that o1.equals(o2) should return false instead of throwing NullPointerException? Would it be a bad idea if wherever possible we rewrite the contract so that anyObject.equals(null) always throw NullPointerException instead?

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  • How to index a date column with null values?

    - by Heinz Z.
    How should I index a date column when some rows has null values? We have to select rows between a date range and rows with null dates. We use Oracle 9.2 and higher. Options I found Using a bitmap index on the date column Using an index on date column and an index on a state field which value is 1 when the date is null Using an index on date column and an other granted not null column My thoughts to the options are: to 1: the table have to many different values to use an bitmap index to 2: I have to add an field only for this purpose and to change the query when I want to retrieve the null date rows to 3: locks tricky to add an field to an index which is not really needed What is the best practice for this case? Thanks in advance Some infos I have read: Oracle Date Index When does Oracle index null column values?

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  • How to get the first non-null value in Java?

    - by froadie
    Is there a Java equivalent of SQL's COALESCE function? That is, is there any way to return the first non-null value of several variables? e.g. Double a = null; Double b = 4.4; Double c = null; I want to somehow have a statement that will return the first non-null value of a, b, and c - in this case, it would return b, or 4.4. (Something like the sql method - return COALESCE(a,b,c)). I know that I can do it explicitly with something like: return a != null ? a : (b != null ? b : c) But I wondered if there was any built-in, accepted function to accomplish this.

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  • How to remove window applet from Gnome3?

    - by Filip Nowak
    I installed today window applet for Gnome3 from this webupd8 post. The effect of the installation shown in the picture. I tried apt-get remove --purge and nothing happens. How do I remove this window applet? http://i.stack.imgur.com/D1s9b.jpg When i try metacity --replace &unity [1] 3171 Checking if settings need to be migrated ...no Checking if internal files need to be migrated ...no Backend : gconf Integration : true Profile : default Adding plugins Skipping upgrade com.canonical.unity.unity.01.upgrade Skipping upgrade com.canonical.unity.unity.02.upgrade Initializing core options...done Initializing bailer options...done Initializing detection options...done Initializing composite options...done Initializing opengl options...done Initializing decor options...done Initializing move options...done Initializing vpswitch options...done Initializing gnomecompat options...done Initializing grid options...done Initializing mousepoll options...done Initializing place options...done Initializing resize options...done Initializing animation options...done Initializing wall options...done Initializing session options...done Initializing workarounds options...done Initializing wobbly options...done compiz (expo) - Warn: failed to bind image to texture Initializing expo options...done Initializing ezoom options...done Initializing staticswitcher options...done Initializing fade options...done Initializing scale options...done Screen geometry changed: 0x0x1920x1080 Initializing unityshell options...done DEBUG 2012-02-19 21:22:40 glib <unknown>:0 Setting to primary screen rect: x=0 y=0 w=1920 h=1080 WARN 2012-02-19 21:22:40 unity.favorites FavoriteStoreGSettings.cpp:138 Unable to load GDesktopAppInfo for 'bluefish.desktop' WARN 2012-02-19 21:22:40 unity.favorites FavoriteStoreGSettings.cpp:138 Unable to load GDesktopAppInfo for 'filezilla.desktop' WARN 2012-02-19 21:22:40 unity.favorites FavoriteStoreGSettings.cpp:138 Unable to load GDesktopAppInfo for 'gimp.desktop' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' WARN 2012-02-19 21:22:40 glib.glib-gobject <unknown>:0 invalid cast from `BamfWindow' to `BamfApplication' Setting Update "texture_filter" Setting Update "sync_to_vblank" Setting Update "fullscreen_visual_bell" Setting Update "panel_opacity" Setting Update "launcher_opacity" Setting Update "icon_size" WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method InfoRequest proxy /com/canonical/unity/lens/applications does not exist WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method SetActive proxy /com/canonical/unity/lens/applications does not exist WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method InfoRequest proxy /com/canonical/unity/lens/commands does not exist WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method SetActive proxy /com/canonical/unity/lens/commands does not exist WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method InfoRequest proxy /com/canonical/unity/lens/files does not exist WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method SetActive proxy /com/canonical/unity/lens/files does not exist WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method InfoRequest proxy /com/canonical/unity/lens/music does not exist WARN 2012-02-19 21:23:32 unity.glib.dbusproxy GLibDBusProxy.cpp:255 Cannot call method SetActive proxy /com/canonical/unity/lens/music does not exist WARN 2012-02-19 21:23:33 unity.iconloader IconLoader.cpp:509 Unable to load contents of file:///usr/share/icons/unity-icon-theme/places/svg/category-available.svg: Blad podczas otwierania pliku: Nie ma takiego pliku ani katalogu WARN 2012-02-19 21:23:33 unity.iconloader IconLoader.cpp:509 Unable to load contents of file:///usr/share/icons/unity-icon-theme/places/svg/category-installed.svg: Blad podczas otwierania pliku: Nie ma takiego pliku ani katalogu

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  • Find all those columns which have only null values, in a MySQL table

    - by Robin v. G.
    The situation is as follows: I have a substantial number of tables, with each a substantial number of columns. I need to deal with this old and to-be-deprecated database for a new system, and I'm looking for a way to eliminate all columns that have - apparently - never been in use. I wanna do this by filtering out all columns that have a value on any given row, leaving me with a set of columns where the value is NULL in all rows. Of course I could manually sort every column descending, but that'd take too long as I'm dealing with loads of tables and columns. I estimate it to be 400 tables with up to 50 (!) columns per table. Is there any way I can get this information from the information_schema? EDIT: Here's an example: column_a column_b column_c column_d NULL NULL NULL 1 NULL 1 NULL 1 NULL 1 NULL NULL NULL NULL NULL NULL The output should be 'column_a' and 'column_c', for being the only columns without any filled in values.

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  • What's the Matlab equivalent of NULL, when it's calling COM/ActiveX methods?

    - by David M
    Hi, I maintain a program which can be automated via COM. Generally customers use VBS to do their scripting, but we have a couple of customers who use Matlab's ActiveX support and are having trouble calling COM object methods with a NULL parameter. They've asked how they do this in Matlab - and I've been scouring Mathworks' COM/ActiveX documentation for a day or so now and can't figure it out. Their example code might look something like this: function do_something() OurAppInstance = actxserver('Foo.Application'); OurAppInstance.Method('Hello', NULL) end where NULL is where in another language, we'd write NULL or nil or Nothing, or, of course, pass in an object. The problem is this is optional (and these are implemented as optional parameters in most, but not all, cases) - these methods expect to get NULL quite often. They tell me they've tried [] (which from my reading seemed the most likely) as well as '', Nothing, 'Nothing', None, Null, and 0. I have no idea how many of those are even valid Matlab keywords - certainly none work in this case. Can anyone help? What's Matlab's syntax for a null pointer / object for use as a COM method parameter? Update: Thanks for all the replies so far! Unfortunately, none of the answers seem to work, not even libpointer. The error is the same in all cases: Error: Type mismatch, argument 2 This parameter in the COM type library is described in RIDL as: HRESULT _stdcall OurMethod([in] BSTR strParamOne, [in, optional] OurCoClass* oParamTwo, [out, retval] VARIANT_BOOL* bResult); The coclass in question implements a single interface descending from IDispatch.

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  • Cast MyEntity To LinqEntity throw a base controller class

    - by Mohammad Kani
    hi there i design a multilayer we appliction andusing LINQ a my data provider i need to user my own Entites instead o LINQ etities. so i created Entities Project and create my entities in it. when i get data from contex and cast them to my entities , everything is ok. but when i want to cast on of my entities to linq entity , an exception thrown. in my linq entity i add CTYPE operator from and to my entities Exp : Public Class BaseController(Of LinqEntity As {BaseEntity, New}, MyEntity As ModuleEntities.BaseEntityInfo) Implements Interfaces.Base(Of ServiceEntity) 'This methd work fine and cast LinqEntity to MyEntity Public Function GetAll() As List(Of MyEntity ) Dim q = (From x In Context.GetTable(Of LinqEntity)() _ Select x).Cast(Of MyEntityBase) End Function Public Sub Update(ByVal entity As MyEntity) 'here is problem 'cast , direct cast , or anything not work Dim x as LinqEntity = entity Me.Context.GetTable(Of LinqEntity).InsertOnSubmit(entity) Me.Context.SubmiChanges() End Sub

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  • Why can one null return be tested but another throws an exception?

    - by mickey
    I want to test if an xml attribute is present. Given this: XmlAttributeCollection PG_attrColl = SomeNodeorAnother.Attributes; This first test works: if (null != PG_attrColl["SomeAttribute"]) "GetNamedItem" is supposed to return null, but the following test throws an exception complaining about the null it returns. if (null != PG_attrColl.GetNamedItem("SomeAttribute").Value;) Why the difference? Just curious.

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  • Best way to check for null values in Java?

    - by Arty-fishL
    I need to check whether the function of an object returns true or false in Java, but that object may be null, so obviously then the function would throw a NullPointerException. This means I need to check if the object is null before checking the value of the function. What is the best way to go about this? I've listed some methods I considered, I just want to know the most sensible one, the one that is best programming practice for Java (opinion?). // method 1 if (foo != null) { if (foo.bar()) { etc... } } // method 2 if (foo != null ? foo.bar() : false) { etc... } // method 3 try { if (foo.bar()) { etc... } } catch (NullPointerException e) { } // method 4 // would this work all the time, would it still call foo.bar()? if (foo != null && foo.bar()) { etc... }

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  • How to list all duplicated rows which may include NULL columns?

    - by Yousui
    Hi guys, I have a problem of listing duplicated rows that include NULL columns. Lemme show my problem first. USE [tempdb]; GO IF OBJECT_ID(N'dbo.t') IS NOT NULL BEGIN DROP TABLE dbo.t END GO CREATE TABLE dbo.t ( a NVARCHAR(8), b NVARCHAR(8) ); GO INSERT t VALUES ('a', 'b'); INSERT t VALUES ('a', 'b'); INSERT t VALUES ('a', 'b'); INSERT t VALUES ('c', 'd'); INSERT t VALUES ('c', 'd'); INSERT t VALUES ('c', 'd'); INSERT t VALUES ('c', 'd'); INSERT t VALUES ('e', NULL); INSERT t VALUES (NULL, NULL); INSERT t VALUES (NULL, NULL); INSERT t VALUES (NULL, NULL); INSERT t VALUES (NULL, NULL); GO Now I want to show all rows that have other rows duplicated with them, I use the following query. SELECT a, b FROM dbo.t GROUP BY a, b HAVING count(*) > 1 which will give us the result: a b -------- -------- NULL NULL a b c d Now if I want to list all rows that make contribution to duplication, I use this query: WITH duplicate (a, b) AS ( SELECT a, b FROM dbo.t GROUP BY a, b HAVING count(*) > 1 ) SELECT dbo.t.a, dbo.t.b FROM dbo.t INNER JOIN duplicate ON (dbo.t.a = duplicate.a AND dbo.t.b = duplicate.b) Which will give me the result: a b -------- -------- a b a b a b c d c d c d c d As you can see, all rows include NULLs are filtered. The reason I thought is that I use equal sign to test the condition(dbo.t.a = duplicate.a AND dbo.t.b = duplicate.b), and NULLs cannot be compared use equal sign. So, in order to include rows that include NULLs in it in the last result, I have change the aforementioned query to WITH duplicate (a, b) AS ( SELECT a, b FROM dbo.t GROUP BY a, b HAVING count(*) > 1 ) SELECT dbo.t.a, dbo.t.b FROM dbo.t INNER JOIN duplicate ON (dbo.t.a = duplicate.a AND dbo.t.b = duplicate.b) OR (dbo.t.a IS NULL AND duplicate.a IS NULL AND dbo.t.b = duplicate.b) OR (dbo.t.b IS NULL AND duplicate.b IS NULL AND dbo.t.a = duplicate.a) OR (dbo.t.a IS NULL AND duplicate.a IS NULL AND dbo.t.b IS NULL AND duplicate.b IS NULL) And this query will give me the answer as I wanted: a b -------- -------- NULL NULL NULL NULL NULL NULL NULL NULL a b a b a b c d c d c d c d Now my question is, as you can see, this query just include two columns, in order to include NULLs in the last result, you have to use many condition testing statements in the query. As the column number increasing, the condition testing statements you need in your query is increasing astonishingly. How can I solve this problem? Great thanks.

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  • Doctrine Mssql uniqueidentifier isn't cast as char or nvarchar when retrieved from the database.

    - by Tres
    When I retrieve a record from the database which has a column of type "uniqueidentifier", Doctrine fills it with "null" rather than the unique id from the database. Some research and testing has brought this down to a PDO/dblib driver issue. When directly querying via PDO, null is returned in place of the unique id. For reference, http://trac.doctrine-project.org/ticket/1096, has a bit on this, however, it was updated 11 months ago with no comment for resolution. A way around this, as mentioned at http://bugs.php.net/bug.php?id=24752&edit=1, is to cast the column as a char. However, it doesn't seem Doctrine exposes the native field type outside of generating models which makes it a bit hard to detect uniqueidentifier types and cast them internally when building the sql query. Has anyone found a workaround for this?

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  • How to order by column with non-null values first in sql

    - by devlife
    I need to write a sql statement to select all users ordered by lastname, firstname. This is the part I know how to do :) What I don't know how to do is to order by non-null values first. Right now I get this: null, null null, null p1Last, p1First p2Last, p2First etc I need to get: p1Last, p1First p2Last, p2First null, null null, null Any thoughts?

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  • Problem in Saving Multi Level Models in YII

    - by Waqar
    My Table structure for user and his adress detail is as follows CREATE TABLE tbl_users ( id bigint(20) unsigned NOT NULL AUTO_INCREMENT, loginname varchar(128) NOT NULL, enabled enum("True","False"), approved enum("True","False"), password varchar(128) NOT NULL, email varchar(128) NOT NULL, role_id int(20) NOT NULL DEFAULT '2', name varchar(70) NOT NULL, co_type enum("S/O","D/O","W/O") DEFAULT "S/O", co_name varchar(70), gender enum("MALE","FEMALE","OTHER") DEFAULT "MALE", dob date DEFAULT NULL, maritalstatus enum("SINGLE","MARRIED","DIVORCED","WIDOWER") DEFAULT "MARRIED", occupation varchar(100) DEFAULT NULL, occupationtype_id int(20) DEFAULT NULL, occupationindustry_id int(20) DEFAULT NULL, contact_id bigint(20) unsigned DEFAULT NULL, signupreason varchar(500), PRIMARY KEY (id), UNIQUE KEY loginname (loginname), UNIQUE KEY email (email), FOREIGN KEY (role_id) REFERENCES tbl_roles (id), FOREIGN KEY (occupationtype_id) REFERENCES tbl_occupationtypes (id), FOREIGN KEY (occupationindustry_id) REFERENCES tbl_occupationindustries (id), FOREIGN KEY (contact_id) REFERENCES tbl_contacts (id) ) ENGINE=InnoDB; CREATE TABLE tbl_contacts ( id bigint(20) unsigned NOT NULL AUTO_INCREMENT, contact_type enum("cres","pres","coff"), address varchar(300) DEFAULT NULL, landmark varchar(100) DEFAULT NULL, district_id int(11) DEFAULT NULL, city_id int(20) DEFAULT NULL, state_id int(20) DEFAULT NULL, pin_id bigint(20) unsigned DEFAULT NULL, area_id bigint(20) unsigned DEFAULT NULL, po_id bigint(20) unsigned DEFAULT NULL, phone1 varchar(20) DEFAULT NULL, phone2 varchar(20) DEFAULT NULL, mobile1 varchar(20) DEFAULT NULL, mobile2 varchar(20) DEFAULT NULL, PRIMARY KEY (id), FOREIGN KEY (district_id) REFERENCES tbl_districts (id), FOREIGN KEY (city_id) REFERENCES tbl_cities (id), FOREIGN KEY (state_id) REFERENCES tbl_states (id) ) ENGINE=InnoDB; CREATE TABLE tbl_states ( id int(20) NOT NULL AUTO_INCREMENT, name varchar(70) DEFAULT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB; CREATE TABLE tbl_districts ( id int(20) NOT NULL AUTO_INCREMENT, name varchar(70) DEFAULT NULL, state_id int(20) DEFAULT NULL, PRIMARY KEY (id), FOREIGN KEY (state_id) REFERENCES tbl_states (id) ) ENGINE=InnoDB; CREATE TABLE tbl_cities ( id int(20) NOT NULL AUTO_INCREMENT, name varchar(70) DEFAULT NULL, district_id int(20) DEFAULT NULL, state_id int(20) DEFAULT NULL, PRIMARY KEY (id), FOREIGN KEY (district_id) REFERENCES tbl_districts (id), FOREIGN KEY (state_id) REFERENCES tbl_states (id) ) ENGINE=InnoDB; The relationship is as follows User has multiple contacts i.e Permanent Address, Current Address, Office Address. Each Contact has state and City. User-Contact-state like this How to save models of this structure in one go. Please provide a reply ASAP

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  • executing null values records

    - by jjj
    i am trying to execute the records that have TotalTime null value from the table NewTimeAttendance...TotalTime datatype nchar(10) select * from newtimeattendance where TotalTime = 'NULL' ....nothing select * from newtimeattendance where TotalTime = 'null' ....nothing select * from newtimeattendance where TotalTime = 'Null' ....nothing select * from newtimeattendance where TotalTime = null ....nothing select * from newtimeattendance where TotalTime = Null ....nothing select * from newtimeattendance where TotalTime = NULL ....nothing when i select the whole table i can see that there is some NULL TotalTime values..!! it is small select statment ..why doesn't it work ? is there a way (special way ) to execute the 'NULL' with nchar type ?! thanks in advance

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  • MiniMax function throws null pointer exception

    - by Sven
    I'm working on a school project, I have to build a tic tac toe game with the AI based on the MiniMax algorithm. The two player mode works like it should. I followed the code example on http://ethangunderson.com/blog/minimax-algorithm-in-c/. The only thing is that I get a NullPointer Exception when I run the code. And I can't wrap my finger around it. I placed a comment in the code where the exception is thrown. The recursive call is returning a null pointer, what is very strange because it can't.. When I place a breakpoint on the null return with the help of a if statement, then I see that there ARE still 2 to 3 empty places.. I probably overlooking something. Hope someone can tell me what I'm doing wrong. Here is the MiniMax code (the tic tac toe code is not important): /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package MiniMax; import Game.Block; import Game.Board; import java.util.ArrayList; public class MiniMax { public static Place getBestMove(Board gameBoard, Block.TYPE player) { Place bestPlace = null; ArrayList<Place> emptyPlaces = gameBoard.getEmptyPlaces(); Board newBoard; //loop trough all the empty places for(Place emptyPlace : emptyPlaces) { newBoard = gameBoard.clone(); newBoard.setBlock(emptyPlace.getRow(), emptyPlace.getCell(), player); //no game won and still room to move if(newBoard.getWinner() == Block.TYPE.NONE && newBoard.getEmptyPlaces().size() > 0) { //is an node (has children) Place tempPlace = getBestMove(newBoard, invertPlayer(player)); //ERROR is thrown here! tempPlace is null. emptyPlace.setScore(tempPlace.getScore()); } else { //is an leaf if(newBoard.getWinner() == Block.TYPE.NONE) { emptyPlace.setScore(0); } else if(newBoard.getWinner() == Block.TYPE.X) { emptyPlace.setScore(-1); } else if(newBoard.getWinner() == Block.TYPE.O) { emptyPlace.setScore(1); } //if this move is better then our prev move, take it! if((bestPlace == null) || (player == Block.TYPE.X && emptyPlace.getScore() < bestPlace.getScore()) || (player == Block.TYPE.O && emptyPlace.getScore() > bestPlace.getScore())) { bestPlace = emptyPlace; } } } //This should never be null, but it does.. return bestPlace; } private static Block.TYPE invertPlayer(Block.TYPE player) { if(player == Block.TYPE.X) { return Block.TYPE.O; } return Block.TYPE.X; } }

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  • SQL: empty string vs NULL value

    - by Jacek Prucia
    I know this subject is a bit controversial and there are a lot of various articles/opinions floating around the internet. Unfortunatelly, most of them assume the person doesn't know what the difference between NULL and empty string is. So they tell stories about surprising results with joins/aggregates and generally do a bit more advanced SQL lessons. By doing this, they absolutely miss the whole point and are therefore useless for me. So hopefully this question and all answers will move subject a bit forward. Let's suppose I have a table with personal information (name, birth, etc) where one of the columns is an email address with varchar type. We assume that for some reason some people might not want to provide an email address. When inserting such data (without email) into the table, there are two available choices: set cell to NULL or set it to empty string (''). Let's assume that I'm aware of all the technical implications of choosing one solution over another and I can create correct SQL queries for either scenario. The problem is even when both values differ on the technical level, they are exactly the same on logical level. After looking at NULL and '' I came to a single conclusion: I don't know email address of the guy. Also no matter how hard i tried, I was not able to sent an e-mail using either NULL or empty string, so apparently most SMTP servers out there agree with my logic. So i tend to use NULL where i don't know the value and consider empty string a bad thing. After some intense discussions with colleagues i came with two questions: am I right in assuming that using empty string for an unknown value is causing a database to "lie" about the facts? To be more precise: using SQL's idea of what is value and what is not, I might come to conclusion: we have e-mail address, just by finding out it is not null. But then later on, when trying to send e-mail I'll come to contradictory conclusion: no, we don't have e-mail address, that @!#$ Database must have been lying! Is there any logical scenario in which an empty string '' could be such a good carrier of important information (besides value and no value), which would be troublesome/inefficient to store by any other way (like additional column). I've seen many posts claiming that sometimes it's good to use empty string along with real values and NULLs, but so far haven't seen a scenario that would be logical (in terms of SQL/DB design). P.S. Some people will be tempted to answer, that it is just a matter of personal taste. I don't agree. To me it is a design decision with important consequences. So i'd like to see answers where opion about this is backed by some logical and/or technical reasons.

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  • Problem with SQL syntax (probably simple)

    - by Bryan Folds
    I'm doing some custom database work for a module for Drupal and I get the following SQL error when trying to create my table: user warning: 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 'DEFAULT NULL, rooms INT DEFAULT NULL, adults INT DEFAULT NULL, children' at line 14 query: CREATE TABLE dr_enquiry ( eId INT unsigned NOT NULL auto_increment, eKey VARCHAR(16) NOT NULL, dateSent INT NOT NULL DEFAULT 0, status VARCHAR(30) NOT NULL DEFAULT 'Unanswered', custName VARCHAR(50) NOT NULL, custEmail VARCHAR(200) NOT NULL, custPhone VARCHAR(25) NOT NULL, custCountry VARCHAR(40) NOT NULL, custIP VARCHAR(11) DEFAULT NULL, offerName VARCHAR(100) NOT NULL, offerURL VARCHAR(200) NOT NULL, arrival DATETIME DEFAULT NULL, departure DEFAULT NULL, rooms INT DEFAULT NULL, adults INT DEFAULT NULL, children INT DEFAULT NULL, childAges VARCHAR(32) DEFAULT NULL, toddlers INT DEFAULT NULL, toddlerAges VARCHAR(32) DEFAULT NULL, catering VARCHAR(255) DEFAULT NULL, comments VARCHAR(255) DEFAULT NULL, agent VARCHAR(100) DEFAULT NULL, voucher VARCHAR(100) DEFAULT NULL, PRIMARY KEY (eId) ) /*!40100 DEFAULT CHARACTER SET UTF8 */ in /home/travelco/public_html/includes/database.inc on line 550.

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  • tomcat5 HTTP 400 BAd Request

    - by Oneiroi
    OS is centOS 5.5 x64, rpm's are as follows: tomcat5-jsp-2.0-api-5.5.23-0jpp.9.el5_5 tomcat5-common-lib-5.5.23-0jpp.9.el5_5 tomcat5-servlet-2.4-api-5.5.23-0jpp.9.el5_5 tomcat5-server-lib-5.5.23-0jpp.9.el5_5 tomcat5-5.5.23-0jpp.9.el5_5 tomcat5-jasper-5.5.23-0jpp.9.el5_5 telnet localhost 8080 Trying 127.0.0.1... Connected to localhost.localdomain (127.0.0.1). Escape character is '^]'. GET / HTTP/1.0 Host: localhost HTTP/1.1 400 Bad Request Server: Apache-Coyote/1.1 Date: Thu, 16 Sep 2010 15:06:21 GMT Connection: close alternatives --display java output: alternatives --display java java - status is manual. link currently points to /usr/lib/jvm/jre1.6.0_21/bin/java /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java - priority 16000 slave keytool: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/keytool slave orbd: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/orbd slave pack200: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/pack200 slave rmid: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/rmid slave rmiregistry: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/rmiregistry slave servertool: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/servertool slave tnameserv: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/tnameserv slave unpack200: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/unpack200 slave jre_exports: /usr/lib/jvm-exports/jre-1.6.0-openjdk.x86_64 slave jre: /usr/lib/jvm/jre-1.6.0-openjdk.x86_64 slave java.1.gz: /usr/share/man/man1/java-java-1.6.0-openjdk.1.gz slave keytool.1.gz: /usr/share/man/man1/keytool-java-1.6.0-openjdk.1.gz slave orbd.1.gz: /usr/share/man/man1/orbd-java-1.6.0-openjdk.1.gz slave pack200.1.gz: /usr/share/man/man1/pack200-java-1.6.0-openjdk.1.gz slave rmid.1.gz: /usr/share/man/man1/rmid-java-1.6.0-openjdk.1.gz slave rmiregistry.1.gz: /usr/share/man/man1/rmiregistry-java-1.6.0-openjdk.1.gz slave servertool.1.gz: /usr/share/man/man1/servertool-java-1.6.0-openjdk.1.gz slave tnameserv.1.gz: /usr/share/man/man1/tnameserv-java-1.6.0-openjdk.1.gz slave unpack200.1.gz: /usr/share/man/man1/unpack200-java-1.6.0-openjdk.1.gz /usr/lib/jvm/jre-1.4.2-gcj/bin/java - priority 1420 slave keytool: /usr/lib/jvm/jre-1.4.2-gcj/bin/keytool slave orbd: (null) slave pack200: (null) slave rmid: (null) slave rmiregistry: /usr/lib/jvm/jre-1.4.2-gcj/bin/rmiregistry slave servertool: (null) slave tnameserv: (null) slave unpack200: (null) slave jre_exports: /usr/lib/jvm-exports/jre-1.4.2-gcj slave jre: /usr/lib/jvm/jre-1.4.2-gcj slave java.1.gz: (null) slave keytool.1.gz: (null) slave orbd.1.gz: (null) slave pack200.1.gz: (null) slave rmid.1.gz: (null) slave rmiregistry.1.gz: (null) slave servertool.1.gz: (null) slave tnameserv.1.gz: (null) slave unpack200.1.gz: (null) /usr/lib/jvm/jre1.6.0_21/bin/java - priority 2 slave keytool: (null) slave orbd: (null) slave pack200: (null) slave rmid: (null) slave rmiregistry: (null) slave servertool: (null) slave tnameserv: (null) slave unpack200: (null) slave jre_exports: (null) slave jre: (null) slave java.1.gz: (null) slave keytool.1.gz: (null) slave orbd.1.gz: (null) slave pack200.1.gz: (null) slave rmid.1.gz: (null) slave rmiregistry.1.gz: (null) slave servertool.1.gz: (null) slave tnameserv.1.gz: (null) slave unpack200.1.gz: (null) Current `best' version is /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java. Same occurs trying HTTP/1.1, and I am at a complete loss as to why.

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  • Trying to import SQL file in a xampp server returns error

    - by Victor_J_Martin
    I have done a ER diagram in Mysql Workbench, and I am trying load in my server with phpMyAdmin, but it returns me the next error: Error SQL Query: -- ----------------------------------------------------- -- Table `BDA`.`UG` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`UG` ( `numero_ug` INT NOT NULL, `nombre` VARCHAR(45) NOT NULL, `segunda_firma_autorizada` VARCHAR(45) NOT NULL, `fecha_creacion` DATE NOT NULL, `nombre_depto` VARCHAR(140) NOT NULL, `dni` INT NOT NULL, `anho_contable` INT NOT NULL, PRIMARY KEY (`numero_ug`), INDEX `nombre_depto_idx` (`nombre_depto` ASC), INDEX `dni_idx` (`dni` ASC), INDEX `anho_contable_idx` (`anho_contable` ASC), CONSTRAINT `nombre_depto` FOREIGN KEY (`nombre_depto`) REFERENCES `BDA`.`Departamento` (`nombre_depto`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `dni` FOREIGN KEY (`dni`) REFERENCES `BDA`.`Trabajador` (`dni`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `anho_contable` FOREIGN KEY (`anho_contable`) REFERENCES `BDA`.`Capitulo_Contable` (`anho_contable`) [...] MySQL said: Documentation #1022 - Can't write; duplicate key in table 'ug' I export the result of the diagram from Mysql Workbench to a SQL file, and this file is what I'm trying to upload. This is the file. I can not find the duplicate key. SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0; SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0; SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL,ALLOW_INVALID_DATES'; CREATE SCHEMA IF NOT EXISTS `BDA` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci ; USE `BDA` ; -- ----------------------------------------------------- -- Table `BDA`.`Departamento` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`Departamento` ( `nombre_depto` VARCHAR(140) NOT NULL, `area_depto` VARCHAR(140) NOT NULL, PRIMARY KEY (`nombre_depto`)) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `BDA`.`Trabajador` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`Trabajador` ( `dni` INT NOT NULL, `direccion` VARCHAR(140) NOT NULL, `nombre` VARCHAR(45) NOT NULL, `apellidos` VARCHAR(140) NOT NULL, `fecha_nacimiento` DATE NOT NULL, `fecha_contrato` DATE NOT NULL, `titulacion` VARCHAR(140) NULL, `nombre_depto` VARCHAR(45) NOT NULL, PRIMARY KEY (`dni`), INDEX `nombre_depto_idx` (`nombre_depto` ASC), CONSTRAINT `nombre_depto` FOREIGN KEY (`nombre_depto`) REFERENCES `BDA`.`Departamento` (`nombre_depto`) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `BDA`.`Capitulo_Contable` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`Capitulo_Contable` ( `anho_contable` INT NOT NULL, `numero_ug` INT NOT NULL, `debe` DOUBLE NOT NULL, `haber` DOUBLE NOT NULL, PRIMARY KEY (`anho_contable`), INDEX `numero_ug_idx` (`numero_ug` ASC), CONSTRAINT `numero_ug` FOREIGN KEY (`numero_ug`) REFERENCES `BDA`.`UG` (`numero_ug`) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `BDA`.`UG` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`UG` ( `numero_ug` INT NOT NULL, `nombre` VARCHAR(45) NOT NULL, `segunda_firma_autorizada` VARCHAR(45) NOT NULL, `fecha_creacion` DATE NOT NULL, `nombre_depto` VARCHAR(140) NOT NULL, `dni` INT NOT NULL, `anho_contable` INT NOT NULL, PRIMARY KEY (`numero_ug`), INDEX `nombre_depto_idx` (`nombre_depto` ASC), INDEX `dni_idx` (`dni` ASC), INDEX `anho_contable_idx` (`anho_contable` ASC), CONSTRAINT `nombre_depto` FOREIGN KEY (`nombre_depto`) REFERENCES `BDA`.`Departamento` (`nombre_depto`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `dni` FOREIGN KEY (`dni`) REFERENCES `BDA`.`Trabajador` (`dni`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `anho_contable` FOREIGN KEY (`anho_contable`) REFERENCES `BDA`.`Capitulo_Contable` (`anho_contable`) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `BDA`.`Cliente` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`Cliente` ( `cif_cliente` INT NOT NULL, `nombre_cliente` VARCHAR(140) NOT NULL, PRIMARY KEY (`cif_cliente`)) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `BDA`.`Ingreso` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`Ingreso` ( `id` INT NOT NULL, `concepto` VARCHAR(45) NOT NULL, `importe` DOUBLE NOT NULL, `fecha` DATE NOT NULL, `cif_cliente` INT NOT NULL, `numero_ug` INT NOT NULL, PRIMARY KEY (`id`), INDEX `cif_cliente_idx` (`cif_cliente` ASC), INDEX `numero_ug_idx` (`numero_ug` ASC), CONSTRAINT `cif_cliente` FOREIGN KEY (`cif_cliente`) REFERENCES `BDA`.`Cliente` (`cif_cliente`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `numero_ug` FOREIGN KEY (`numero_ug`) REFERENCES `BDA`.`UG` (`numero_ug`) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `BDA`.`Proveedor` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`Proveedor` ( `cif_proveedor` INT NOT NULL, `nombre_proveedor` VARCHAR(140) NOT NULL, PRIMARY KEY (`cif_proveedor`)) ENGINE = InnoDB; -- ----------------------------------------------------- -- Table `BDA`.`Gasto` -- ----------------------------------------------------- CREATE TABLE IF NOT EXISTS `BDA`.`Gasto` ( `id` INT NOT NULL, `concepto` VARCHAR(45) NOT NULL, `importe` DOUBLE NOT NULL, `fecha` DATE NOT NULL, `factura` INT NOT NULL, `cif_proveedor` INT NOT NULL, `numero_ug` INT NOT NULL, PRIMARY KEY (`id`), INDEX `cif_proveedor_idx` (`cif_proveedor` ASC), INDEX `numero_ug_idx` (`numero_ug` ASC), CONSTRAINT `cif_proveedor` FOREIGN KEY (`cif_proveedor`) REFERENCES `BDA`.`Proveedor` (`cif_proveedor`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `numero_ug` FOREIGN KEY (`numero_ug`) REFERENCES `BDA`.`UG` (`numero_ug`) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE = InnoDB; SET SQL_MODE=@OLD_SQL_MODE; SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS; SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS; Thanks for your advices.

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  • How to implement List, Set, and Map in null free design?

    - by Pyrolistical
    Its great when you can return a null/empty object in most cases to avoid nulls, but what about Collection like objects? In Java, Map returns null if key in get(key) is not found in the map. The best way I can think of to avoid nulls in this situation is to return an Entry<T> object, which is either the EmptyEntry<T>, or contains the value T. Sure we avoid the null, but now you can have a class cast exception if you don't check if its an EmptyEntry<T>. Is there a better way to avoid nulls in Map's get(K)? And for argument sake, let's say this language don't even have null, so don't say just use nulls.

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  • NullPointerException in javax.swing.text.SimpleAttributeSet.addAttribute

    - by Paul Reiners
    Has anyone ever seen an exception like this?: ERROR: java.lang.NullPointerException: null at java.util.Hashtable.put(null:-1) at javax.swing.text.SimpleAttributeSet.addAttribute(null:-1) at javax.swing.text.SimpleAttributeSet.addAttributes(null:-1) at javax.swing.text.StyledEditorKit.createInputAttributes(null:-1) at javax.swing.text.StyledEditorKit$AttributeTracker.updateInputAttributes(null:-1) at javax.swing.text.StyledEditorKit$AttributeTracker.caretUpdate(null:-1) at javax.swing.text.JTextComponent.fireCaretUpdate(null:-1) at javax.swing.text.JTextComponent$MutableCaretEvent.fire(null:-1) at javax.swing.text.JTextComponent$MutableCaretEvent.mouseReleased(null:-1) at java.awt.AWTEventMulticaster.mouseReleased(null:-1) at java.awt.AWTEventMulticaster.mouseReleased(null:-1) at java.awt.Component.processMouseEvent(null:-1) at javax.swing.JComponent.processMouseEvent(null:-1) at java.awt.Component.processEvent(null:-1) at java.awt.Container.processEvent(null:-1) at java.awt.Component.dispatchEventImpl(null:-1) at java.awt.Container.dispatchEventImpl(null:-1) at java.awt.Component.dispatchEvent(null:-1) at java.awt.LightweightDispatcher.retargetMouseEvent(null:-1) at java.awt.LightweightDispatcher.processMouseEvent(null:-1) at java.awt.LightweightDispatcher.dispatchEvent(null:-1) at java.awt.Container.dispatchEventImpl(null:-1) at java.awt.Window.dispatchEventImpl(null:-1) at java.awt.Component.dispatchEvent(null:-1) at java.awt.EventQueue.dispatchEvent(null:-1) at java.awt.EventDispatchThread.pumpOneEventForFilters(null:-1) at java.awt.EventDispatchThread.pumpEventsForFilter(null:-1) at java.awt.EventDispatchThread.pumpEventsForHierarchy(null:-1) at java.awt.EventDispatchThread.pumpEvents(null:-1) at java.awt.EventDispatchThread.pumpEvents(null:-1) at java.awt.EventDispatchThread.run(null:-1) I wish I could tell you an easy way to reproduce this, but I can’t. It’s happening in a Java Swing application I maintain. It happens infrequently and the application is quite complex. I know it’s a bit of a long shot just showing this stack trace, but I thought I’d try.

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