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  • null-coalescing operator or conditional operator

    - by rkrauter
    Which coding style do you prefer: object o = new object(); //string s1 = o ?? "Tom"; // Cannot implicitly convert type 'object' to 'string' CS0266 string s3 = Convert.ToString(o ?? "Tom"); string s2 = (o != null) ? o.ToString() : "Tom"; s2 or s3? Is it possible to make it shorter? s1 does not obviously work.

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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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  • 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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  • Null Safe dereferencing in Java like ?. in Groovy using Maybe monad

    - by Sathish
    I'm working on a codebase ported from Objective C to Java. There are several usages of method chaining without nullchecks dog.collar().tag().name() I was looking for something similar to safe-dereferencing operator ?. in Groovy instead of having nullchecks dog.collar?.tag?.name This led to Maybe monad to have the notion of Nothing instead of Null. But all the implementations of Nothing i came across throw exception when value is accessed which still doesn't solve the chaining problem. I made Nothing return a mock, which behaves like NullObject pattern. But it solves the chaining problem. Is there anything wrong with this implementation of Nothing? [http://github.com/sathish316/jsafederef/blob/master/src/s2k/util/safederef/Nothing.java] As far as i can see 1. It feels odd to use mocking library in code 2. It doesn't stop at the first null. 3. How do i distinguish between null result because of null reference or name actually being null? How is it distinguished in Groovy code?

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  • Passing null as a param for replace() in javascript behaving weird?

    - by Babiker
    I have the follwing jQuery: $("#textArea").keyup(function(){ var textAreaValue = $("textArea"); if(!textArea.value.indexOf("some string")){ textArea.value = textArea.value.replace("some string",null); alert("It was there!"); } }); Is it normal for element.value.replace("some string",null); to replace "some string" with "null"as a string? And if normal can you please explain why? I have tested it with element.value.replace("some string",""), and that works fine, so what would be the difference between null and ""? Thanks in advance.

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  • Creating a Mysql view to SELECT coloumns from different tables

    - by user330429
    I need help in constructing a VIEW on 4 tables. The view should contain coloumns: ER.ID, ER.EMPID, ER.CUSTID, ER.STATUS, ER.DATEREPORTED, ER.REPORT, EB.NAME, CR.CUSTNAME, CR.LOCID, CL.LOCNAME, DI.DEPTNAME ALIASES EMP_REPORT ER , EMP_BIO EB, CUST_RECORD CR, CUST_LOC CL, DEPT_ID DI THE DATA MODELS ARE: describe EMP_REPORT; +--------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------+-------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | empid | int(11) | NO | | NULL | | | custid | int(11) | NO | | NULL | | | status | varchar(32) | NO | | NULL | | | datereported | bigint(20) | NO | | NULL | | | report | text | YES | | NULL | | +--------------+-------------+------+-----+---------+----------------+ describe EMP_BIO; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | empid | int(11) | NO | PRI | NULL | | | name | varchar(56) | NO | | NULL | | | sex | char(1) | NO | | NULL | | | deptid | int(11) | NO | | NULL | | | email | varchar(32) | NO | | NULL | | | mobile | bigint(20) | YES | | NULL | | | gtlk | varchar(32) | YES | | NULL | | | skype | varchar(32) | YES | | NULL | | | cvid | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ describe CUST_RECORD; +----------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------+--------------+------+-----+---------+----------------+ | custid | int(11) | NO | PRI | NULL | auto_increment | | custname | varchar(32) | NO | | NULL | | | address | varchar(255) | YES | | NULL | | | contactp | varchar(32) | YES | | NULL | | | mobile | bigint(20) | YES | | NULL | | | locid | int(11) | NO | | NULL | | | remarks | text | YES | | NULL | | | date | int(11) | YES | | NULL | | | addedby | int(11) | YES | | NULL | | +----------+--------------+------+-----+---------+----------------+ describe CUST_LOC; +---------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------+-------------+------+-----+---------+-------+ | locid | int(11) | NO | PRI | 0 | | | locname | varchar(32) | NO | | NULL | | +---------+-------------+------+-----+---------+-------+ describe DEPT_ID; +----------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------+-------------+------+-----+---------+-------+ | deptid | int(11) | NO | | NULL | | | deptname | varchar(32) | YES | | NULL | | +----------+-------------+------+-----+---------+-------+ The table EMP_REPORT contains reports submitted by employees, all the coloumns in it needs to be fetched. The empid in this table should be used to fetch corresponding name in EMP_BIO (employee biodata) table. The custid in EMP_REPORT should be used to fetch corresponding locid in CUST_RECORD(customer record) which is used to fetch locname in CUST_LOC(customer location) table. The empid in EMP_REPORT is used to fetch corresponding deptid in EMP_BIO table which is then used to fetch corresponding deptname from DEPT_ID(department id) table. I tried constructing view using union of different select queries, but dint get proper results. Please help me. Thanks in advance. PS: sorry for my poor english

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  • How can I match a match a null byte (0x00) in the Visual Studio binary editor with a find using a re

    - by Paul K
    Open a file in the Visual Studio binary editor that contains a null byte (0x00), then use the Quick Find feature (Ctrl +F) to find null bytes. I would have thought I could use a regular expression such as \x00 to match null bytes but it doesn't work. Searching for any other hex value using this method works fine. Is this a VS bug, 'feature', or am I just missing something? Is there a work around?

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  • How to assign a value of a property to a var ONLY if the object isn't null

    - by Blankman
    In my code, is there a shorthand that I can use to assign a variable the value of a object's property ONLY if the object isn't null? string username = SomeUserObject.Username; // fails if null I know I can do a check like if(SomeUserObject != null) but I think I saw a shorthand for this kind of test. I tried: string username = SomeUserObject ?? "" : SomeUserObject.Username; But that doesn't work.

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  • How to check if my string is equal to null?

    - by Roman
    I want to perform some action ONLY IF my string has a meaningful value. So, I tried this. if (!myString.eqauls("")) { doSomething } and this if (!myString.eqauls(null)) { doSomething } and this if ( (!myString.eqauls("")) && (!myString.eqauls(null))) { doSomething } and this if ( (!myString.eqauls("")) && (myString!=null)) { doSomething } and this if ( myString.length()>0) { doSomething } And in all cases my program doSomething in spite on the fact that my string IS EMPTY. It equals to null. So, what is wrong with that?

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  • Using "null" in jQuery functions. Is this okay?

    - by Nick
    My database consists of some entries which are NULL (so they don't affect max, min, etc..). When I pull all of the data from the database, I need to repopulate form fields with the values. Using .val(value) where value = NULL seems to work without any problems, but I'm not sure if this is a valid way to go about this. It doesn't say anything in the jQuery documentation (that I can find) about using NULL as parameters to functions.

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  • C++ standard: dereferencing NULL pointer to get a reference?

    - by shoosh
    I'm wondering about what the C++ standard says about code like this: int* ptr = NULL; int& ref = *ptr; int* ptr2 = &ref; In practice the result is that ptr2 is NULL but I'm wondering, is this just an implementation detail or is this well defined in the standard? Under different circumstances a dereferencing of a NULL pointer should result in a crash but here I'm dereferencing it to get a reference which is implemented by the compiler as a pointer so there's really no actual dereferencing of NULL.

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  • inserting null values in datetime column and integer column

    - by reggie
    I am using C# and developing a winform application. I have a project class which has the project attributes. the constructor of the project class is as follows: newProject = new Project(GCD_ID.IsNull() ? (int?)null : Convert.ToInt32(GCD_ID), txt_Proj_Desc.Text, txt_Prop_Name.Text, ST.ID.ToString().IsNull() ? null: ST.ID.ToString(), cmbCentre.Text, SEC.ID.ToString().IsNull() ? null : SEC.ID.ToString(), cmbZone.Text, FD.ID.ToString().IsNull() ? null : FD.ID.ToString(), DT.ID.ToString().IsNull() ? null : DT.ID.ToString(), OP.ID.ToString().IsNull() ? null : OP.ID.ToString(), T.ID.ToString().IsNull() ? null : T.ID.ToString(), CKV.ID.ToString().IsNull() ? null : CKV.ID.ToString(), STAT.ID.ToString().IsNull() ? null : STAT.ID.ToString(), MW.IsNull() ? (Double?)null : Convert.ToDouble(MW), txt_Subject.Text, Ip_Num.IsNull() ? (int?)null : Convert.ToInt32(Ip_Num), H1N_ID.IsNull() ? (int?)null : Convert.ToInt32(H1N_ID), NOMS_Slip_Num.IsNull() ? (int?)null : Convert.ToInt32(NOMS_Slip_Num), NMS_Updated.IsNull() ? (DateTime?)null : Convert.ToDateTime(NMS_Updated), Received_Date.IsNull() ? (DateTime?)null : Convert.ToDateTime(Received_Date), Actual_IS_Date.IsNull() ? (DateTime?)null : Convert.ToDateTime(Actual_IS_Date), Scheduled_IS_Date.IsNull() ? (DateTime?)null : Convert.ToDateTime(Scheduled_IS_Date), UpSt.ID.ToString().IsNull() ? null : UpSt.ID.ToString(), UpFd.ID.ToString().IsNull() ? null : UpFd.ID.ToString(), txtHVCircuit.Text, cmbbxSIA.Text); My problem is that i cannot insert values into the database when the datetime variables and the integer variables are null. all this data are assigned to the variable from textboxes on the form.. bELOW is the database function which takes in all the variables and insert them into the database. public static void createNewProject(int? GCD_ID, string Project_Desc, string Proponent_Name, int Station_ID, string OpCentre, int Sector_ID, string PLZone, int Feeder, int DxTx_ID, int OpControl_ID, int Type_ID, int ConnKV_ID, int Status_ID, double? MW, string Subject, int? Ip_Num, int? H1N_ID, int? NOMS_Slip_Num, DateTime? NMS_Updated, DateTime? Received_Date, DateTime? Actual_IS_Date, DateTime? Scheduled_IS_Date, int UP_Station_ID, int UP_Feeder_ID, string @HV_Circuit, string SIA_Required) { SqlConnection conn = null; try { //Takes in all the employee details to be added to the database. conn = new SqlConnection(databaseConnectionString); conn.Open(); SqlCommand cmd = new SqlCommand("createNewProject", conn); cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.Add(new SqlParameter("GCD_ID", GCD_ID)); cmd.Parameters.Add(new SqlParameter("Project_Desc", MiscFunctions.Capitalize(Project_Desc))); cmd.Parameters.Add(new SqlParameter("Proponent_Name", MiscFunctions.Capitalize(Proponent_Name))); cmd.Parameters.Add(new SqlParameter("Station_ID", Station_ID)); cmd.Parameters.Add(new SqlParameter("OpCentre", OpCentre)); cmd.Parameters.Add(new SqlParameter("Sector_ID", Sector_ID)); cmd.Parameters.Add(new SqlParameter("PLZone", PLZone)); cmd.Parameters.Add(new SqlParameter("Feeder", Feeder)); cmd.Parameters.Add(new SqlParameter("DxTx_ID", DxTx_ID)); cmd.Parameters.Add(new SqlParameter("OpControl_ID", OpControl_ID)); cmd.Parameters.Add(new SqlParameter("Type_ID", Type_ID)); cmd.Parameters.Add(new SqlParameter("ConnKV_ID", ConnKV_ID)); cmd.Parameters.Add(new SqlParameter("Status_ID", Status_ID)); cmd.Parameters.Add(new SqlParameter("MW", MW)); cmd.Parameters.Add(new SqlParameter("Subject", Subject)); cmd.Parameters.Add(new SqlParameter("Ip_Num", Ip_Num)); cmd.Parameters.Add(new SqlParameter("H1N_ID", H1N_ID)); cmd.Parameters.Add(new SqlParameter("NOMS_Slip_Num", NOMS_Slip_Num)); cmd.Parameters.Add(new SqlParameter("NMS_Updated", NMS_Updated)); cmd.Parameters.Add(new SqlParameter("Received_Date", Received_Date)); cmd.Parameters.Add(new SqlParameter("Actual_IS_Date", Actual_IS_Date)); cmd.Parameters.Add(new SqlParameter("Scheduled_IS_Date", Scheduled_IS_Date)); cmd.Parameters.Add(new SqlParameter("UP_Station_ID", UP_Station_ID)); cmd.Parameters.Add(new SqlParameter("UP_Feeder_ID", UP_Feeder_ID)); cmd.Parameters.Add(new SqlParameter("HV_Circuit", HV_Circuit)); cmd.Parameters.Add(new SqlParameter("SIA_Required", SIA_Required)); cmd.ExecuteNonQuery(); } catch (Exception e) //returns if error incurred. { MessageBox.Show("Error occured in createNewProject" + Environment.NewLine + e.ToString()); } finally { if (conn != null) { conn.Close(); } } } My question is, how do i insert values into the database. please please help

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  • MySQL load data null values

    - by SP1
    Hello, I have a file that can contain from 3 to 4 columns of numerical values which are separated by comma. Empty fields are defined with the exception when they are at the end of the row: 1,2,3,4,5 1,2,3,,5 1,2,3 The following table was created in MySQL: +-------+--------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+--------+------+-----+---------+-------+ | one | int(1) | YES | | NULL | | | two | int(1) | YES | | NULL | | | three | int(1) | YES | | NULL | | | four | int(1) | YES | | NULL | | | five | int(1) | YES | | NULL | | +-------+--------+------+-----+---------+-------+ I am trying to load the data using MySQL LOAD command: load data infile '/tmp/testdata.txt' into table moo fields terminated by "," lines terminated by "\n"; The resulting table: +------+------+-------+------+------+ | one | two | three | four | five | +------+------+-------+------+------+ | 1 | 2 | 3 | 4 | 5 | | 1 | 2 | 3 | 0 | 0 | | 1 | 2 | 3 | NULL | NULL | +------+------+-------+------+------+ The problem lies with the fact that when a field is empty in the raw data and is not defined, MySQL for some reason does not use the columns default value (which is NULL) and uses zero. NULL is used correctly when the field is missing alltogether. Unfortunately, I have to be able to distinguish between NULL and 0 at this stage so any help would be appreciated. Thanks S.

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