Search Results

Search found 18153 results on 727 pages for 'null coalescing'.

Page 5/727 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

  • how to count NULL categories in one SQL question

    - by grzes
    hi, i have a blog application were Post belongsTo Category and Category hasMany Post Post can have a Category or not - in latter case NULL value is present in Post.category_id field. Now i would like to have following category count with single SQL query category|post_count -------------- PHP | 2 JavaScript | 4 SomeOtherCat | 1 NULL | 3 The clue here is that i also want to count posts without category (NULL row above). Is it posibble with one SQL query?

    Read the article

  • Why doesn't list.get(0).equals(null) work?

    - by Jessy
    The first index is set to null (empty), but it doesn't print the right output, why? //set the first index as null and the rest as "High" String a []= {null,"High","High","High","High","High"}; //add array to arraylist ArrayList<Object> choice = new ArrayList<Object>(Arrays.asList(a)); for(int i=0; i<choice.size(); i++){ if(i==0){ if(choice.get(0).equals(null)) System.out.println("I am empty"); //it doesn't print this output } }

    Read the article

  • Request Coalescing in Nginx

    - by Marcel Jackwerth
    I have an image resize server sitting behind an nginx server. On a cold cache two clients requesting the same file could trigger two resize jobs. client-01.net GET /resize.do/avatar-1234567890/300x200.png client-02.net GET /resize.do/avatar-1234567890/300x200.png It would be great if only one of the requests could go through to the backend in this situation (while the other client is set 'on-hold'). In Varnish there seems to be such a feature, called Request Coalescing. However that seems to be a Varnish-specific term. Is there something similar for Nginx?

    Read the article

  • Why does my token return NULL and how can I fix it?(c++)

    - by Van
    I've created a program to get a string input from a user and parse it into tokens and move a robot according to the input. The program is supposed to recognize these inputs(where x is an integer): "forward x" "back x" "turn left x" "turn right x" and "stop". The program does what it's supposed to for all commands except for "stop". When I type "stop" the program prints out "whats happening?" because I've written a line which states: if(token == NULL) { cout << "whats happening?" << endl; } Why does token get NULL, and how can I fix this so it will read "stop" properly? here is the code: bool stopper = 0; void Navigator::manualDrive() { VideoStream video(&myRobot, 0);//allows user to see what robot sees video.startStream(); const int bufSize = 42; char uinput[bufSize]; char delim[] = " "; char *token; while(stopper == 0) { cout << "Enter your directions below: " << endl; cin.getline(uinput,bufSize); Navigator::parseInstruction(uinput); } } /* parseInstruction(char *c) -- parses cstring instructions received * and moves robot accordingly */ void Navigator::parseInstruction(char * uinput) { char delim[] = " "; char *token; // cout << "Enter your directions below: " << endl; // cin.getline (uinput, bufSize); token=strtok(uinput, delim); if(token == NULL) { cout << "whats happening?" << endl; } if(strcmp("forward", token) == 0) { int inches; token = strtok(NULL, delim); inches = atoi (token); double value = fabs(0.0735 * fabs(inches) - 0.0550); myRobot.forward(1, value); } else if(strcmp("back",token) == 0) { int inches; token = strtok(NULL, delim); inches = atoi (token); double value = fabs(0.0735 * fabs(inches) - 0.0550); myRobot.backward(1/*speed*/, value/*time*/); } else if(strcmp("turn",token) == 0) { int degrees; token = strtok(NULL, delim); if(strcmp("left",token) == 0) { token = strtok(uinput, delim); degrees = atoi (token); double value = fabs(0.00467 * degrees - 0.04); myRobot.turnLeft(1/*speed*/, value/*time*/); } else if(strcmp("right",token) == 0) { token = strtok(uinput, delim); degrees = atoi (token); double value = fabs(0.00467 * degrees - 0.04); myRobot.turnRight(1/*speed*/, value/*time*/); } } else if(strcmp("stop",token) == 0) { stopper = 1; } else { std::cerr << "Unknown command '" << token << "'\n"; } } /* autoDrive() -- reads in file from ifstream, parses * and moves robot according to instructions in file */ void Navigator::autoDrive(string filename) { const int bufSize = 42; char fLine[bufSize]; ifstream infile; infile.open("autodrive.txt", fstream::in); while (!infile.eof()) { infile.getline(fLine, bufSize); Navigator::parseInstruction(fLine); } infile.close(); } I need this to break out of the while loop and end manualDrive because in my driver program the next function called is autoDrive.

    Read the article

  • Sockets receiving null (Android)

    - by Henrik
    I have a android app that is communicating with a server (written in java). Between these two parts I have established a Socket connection and want to send data. The problem I am having is that sometimes, for some users, the information that reaches the server is null. This works (for all phones, all users): Server: int a = Integer.parseInt(in.readLine()); int b = Integer.parseInt(in.readLine()); int c = Integer.parseInt(in.readLine()); int d = Integer.parseInt(in.readLine()); String checksum = in.readLine(); String model = in.readLine(); String device = in.readLine(); String name = in.readLine(); Client: out.println(a); out.println(b); out.println(c); out.println(d); out.println(hash); out.println(Build.MODEL); out.println(Build.DEVICE); String name = fixName(); out.print(name); out.flush(); This does not work (for some users): Server: int a = Integer.parseInt(in.readLine()); String checksum = in.readLine(); String model = in.readLine(); String device = in.readLine(); String name = in.readLine(); String msg = in.readLine(); int version = -1; String test = "hej"; try{ test = in.readLine(); version = Integer.parseInt(test); }catch(Exception e){ e.printStackTrace(); } Client: out.println(a); out.println(hash); out.println(Build.MODEL); out.println(Build.DEVICE); String name = fixName(); if(name == null) name = "John Doe"; out.println(name); String msg = fixMsg(); if(msg == null) name = "nada"; out.println(msg); out.println(curversion); out.flush(); Sometimes, in the second case, the name, msg, and version (the string test) are null at the server side. The catch is triggered because test is null. curversion,a are ints, the rest are strings. Any ideas?

    Read the article

  • Git on Windows 7 expecting Linux? /dev/null not found error

    - by Klikini
    I have installed git (not GitHub) on Windows 7 x64 Home Premium, and I cannot get it to work. Opening Git Bash outputs the following: Welcome to Git (version 1.9.4-preview20140815) Run 'git help git' to display the help index. Run 'get help <command>' to display help for specific commands. sh.exe": /dev/null: No such file or directory sh.exe": /dev/null: No such file or directory sh.exe": /dev/null: No such file or directory sh.exe": /dev/null: No such file or directory sh.exe": /dev/null: No such file or directory sh.exe": /dev/null: No such file or directory Andy@ANDY-DELL ~ $ If I open the Git GUI, I get a this box: Title: git-gui: fatal error Content: fatal: open /dev/null or dup failed: No such file or directory Git Gui requires Git 1.5.0 or later. I also tried GitHub for Windows, but I got an internet connection error when attempting to clone a repo, even though my connection is fine. Is this possibly related? I have learned so far that /dev/null is the Linux version of the Windows NUL, but why is it trying to do this on Windows? Thanks in advance.

    Read the article

  • NHibernate.PropertyValueException : not-null property references a null or transient

    - by frosty
    I am getting the following exception. NHibernate.PropertyValueException : not-null property references a null or transient Here are my mapping files. Product <class name="Product" table="Products"> <id name="Id" type="Int32" column="Id" unsaved-value="0"> <generator class="identity"/> </id> <set name="PriceBreaks" table="PriceBreaks" generic="true" cascade="all" inverse="true" > <key column="ProductId" /> <one-to-many class="EStore.Domain.Model.PriceBreak, EStore.Domain" /> </set> </class> Price Breaks <class name="PriceBreak" table="PriceBreaks"> <id name="Id" type="Int32" column="Id" unsaved-value="0"> <generator class="identity"/> </id> <property name="ProductId" column="ProductId" type="Int32" not-null="true" /> <many-to-one name="Product" column="ProductId" not-null="true" cascade="all" class="EStore.Domain.Model.Product, EStore.Domain" /> </class> I get the exception on the following method [Test] public void Can_Add_Price_Break() { IPriceBreakRepository repo = new PriceBreakRepository(); var priceBreak = new PriceBreak(); priceBreak.ProductId = 19; repo.Add(priceBreak); Assert.Greater(priceBreak.Id, 0); }

    Read the article

  • Binding a null variable in a PreparedStatement

    - by Paul Tomblin
    I swear this used to work, but it's not in this case. I'm trying to match col1, col2 and col3, even if one or more of them is null. I know that in some languages I've had to resort to circumlocutions like ((? is null AND col1 is null) OR col1 = ?). Is that required here? PreparedStatement selStmt = getConn().prepareStatement( "SELECT * " + "FROM tbl1 " + "WHERE col1 = ? AND col2 = ? and col3 = ?"); try { int col = 1; setInt(selStmt, col++, col1); setInt(selStmt, col++, col2); setInt(selStmt, col++, col3); ResultSet rs = selStmt.executeQuery(); try { while (rs.next()) { // process row } } finally { rs.close(); } } finally { selStmt.close(); } // Does the equivalient of stmt.setInt(col, i) but preserves nullness. protected static void setInt(PreparedStatement stmt, int col, Integer i) throws SQLException { if (i == null) stmt.setNull(col, java.sql.Types.INTEGER); else stmt.setInt(col, i); }

    Read the article

  • What is a NULL value

    - by Adi
    I am wondering , what exactly is stored in the memory when we say a particular variable pointer to be NULL. suppose I have a structure, say typdef struct MEM_LIST MEM_INSTANCE; struct MEM_LIST { char *start_addr; int size; MEM_INSTANCE *next; }; MEM_INSTANCE *front; front = (MEM_INSTANCE*)malloc(sizeof(MEM_INSTANCE*)); -1) If I make front=NULL. What will be the value which actually gets stored in the different fields of the front, say front-size ,front-start_addr. Is it 0 or something else. I have limited knowledge in this NULL thing. -2) If I do a free(front); It frees the memory which is pointed out by front. So what exactly free means here, does it make it NULL or make it all 0. -3) What can be a good strategy to deal with initialization of pointers and freeing them . Thanks in advance

    Read the article

  • Improving performance in this query

    - by Luiz Gustavo F. Gama
    I have 3 tables with user logins: sis_login = administrators tb_rb_estrutura = coordinators tb_usuario = clients I created a VIEW to unite all these users by separating them by levels, as follows: create view `login_names` as select `n1`.`cod_login` as `id`, '1' as `level`, `n1`.`nom_user` as `name` from `dados`.`sis_login` `n1` union all select `n2`.`id` as `id`, '2' as `level`, `n2`.`nom_funcionario` as `name` from `tb_rb_estrutura` `n2` union all select `n3`.`cod_usuario` as `id`, '3' as `level`, `n3`.`dsc_nome` as `name` from `tb_usuario` `n3`; So, can occur up to three ids repeated for different users, which is why I separated by levels. This VIEW is just to return me user name, according to his id and level. considering it has about 500,000 registered users, this view takes about 1 second to load. too much time, but is becomes very small when I need to return the latest posts on the forum of my website. The tables of the forums return the user id and level, then look for a name in this VIEW. I have registered 18 forums. When I run the query, it takes one second for each forum = 18 seconds. OMG. This page loads every time somebody enter my website. This is my query: select `x`.`forum_id`, `x`.`topic_id`, `l`.`nome` from ( select `t`.`forum_id`, `t`.`topic_id`, `t`.`data`, `t`.`user_id`, `t`.`user_level` from `tb_forum_topics` `t` union all select `a`.`forum_id`, `a`.`topic_id`, `a`.`data`, `a`.`user_id`, `a`.`user_level` from `tb_forum_answers` `a` ) `x` left outer join `login_names` `l` on `l`.`id` = `x`.`user_id` and `l`.`level` = `x`.`user_level` group by `x`.`forum_id` asc USING EXPLAIN: id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using temporary; Using filesort 1 PRIMARY <derived4> ALL NULL NULL NULL NULL 530415 4 DERIVED n1 ALL NULL NULL NULL NULL 114 5 UNION n2 ALL NULL NULL NULL NULL 2 6 UNION n3 ALL NULL NULL NULL NULL 530299 NULL UNION RESULT ALL NULL NULL NULL NULL NULL 2 DERIVED t ALL NULL NULL NULL NULL 3 3 UNION r ALL NULL NULL NULL NULL 3 NULL UNION RESULT ALL NULL NULL NULL NULL NULL Somebody can help me or give a suggestion?

    Read the article

  • webpart context.session is null

    - by tbischel
    I've been using the session array to store a state variable for my webpart... so I have a property like this: public INode RootNode { get { return this.Context.Session["RootNode"] as INode; } set { this.Context.Session["RootNode"] = value as object; } } This usually works fine. I've discovered that sometimes, the context.session variable will be null. I'd like to know what are the conditions that cause the session to be null in the first place, and whats the best way to persist my object when this happens? Can I just assign a new HttpSessionState object to the context, or does that screw things up? Edit: Ok, so its not just the session that is null... the whole context is screwed up. When the webpart enters the init, the context is fine... but when it reaches the dropbox selectedindexchange postback event (the dropbox contains node id's to use to set the rootnode variable), the context contains mostly null properties. also, it only seems to happen when certain id's are selected. This looks more like some kind of weird bug on my end than a problem with my understanding of the session.

    Read the article

  • JSON Feed Returning null while using jQuery getJSON

    - by Oscar Godson
    http://portlandonline.com/shared/cfm/json.cfm?c=27321 It's returning null. I don't really have access to this. I have to have a server admin update the feed to my liking, so if you can tell me how to get this to work as is, without adding tags to my HTML please let me know. I will be using this with jQuery, and ive been trying to use getJSON which is what returns null. $.getJSON('http://portlandonline.com/shared/cfm/json.cfm?c=27321',function(json){ alert(json); }); that returns null. But if i use a flickr feed for example, it works fine. it returns what it should, [onject Object]. Any ideas?

    Read the article

  • When would ShowDialog() return null?

    - by Joe White
    WPF's Window.ShowDialog method returns a nullable boolean. So does CommonDialog.ShowDialog. Now, I understand cases where these would return false (user clicked Cancel or pressed Esc), and when they would return true (code sets Window.DialogResult to true, probably in response to OK being clicked). But null? My first thought is that clicking the title bar's Close button might return null. But the docs state (and I confirmed by testing) that the title-bar Close button is treated as a Cancel. So when would Window.ShowDialog or CommonDialog.ShowDialog ever return null?

    Read the article

  • check if(country == @"(null)" doesn't work

    - by Sean
    hi all, I got the problem that the if-statement doesn't work. After the first code line the variable contains the value "(null)", because the user who picked the contact from his iphone address book doesn't set the country key for this contact, so far so good. but if I check the variable, it won't be true, but the value is certainly "(null)"... does someone have an idea? NSString *country = [NSString [the dict objectForKey:(NSString *)kABPersonAddressCountryKey]]; if(country == @"(null)") { country = @""; } thanks in advance sean

    Read the article

  • How to avoid null pointer error

    - by Jessy
    I trying to find whether the elements of 2 arrayLists are match or not. But this code give me error Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException since some of the elements are null. How can I solved this problem? String level []={"High","High","High","High","High","High"}; ArrayList<Object> n = new ArrayList<Object>(Arrays.asList(level)); String choice []={null,"High","Low","High",null,"Medium"}; ArrayList<Object> m = new ArrayList<Object>(Arrays.asList(choice)); //Check if the two arrayList are identical for(int i=0; i<m.size(); i++){ if(!(m.get(i).equals(n.get(i)))){ result= true; break; } } return result; }

    Read the article

  • NULL handling with subselect in Hibernate Criteria API

    - by Jens Schauder
    I'm constructing a Hibernate Criterion, using a subselect as follows DetachedCriteria subselect = DetachedCriteria.forClass(NhmCode.class, "sub"); // the subselect selecting the maximum 'validFrom' subselect.add(Restrictions.le("validFrom", new Date())); // it should be in the past (null needs handling here) subselect.add(Property.forName("sub.lifeCycle").eqProperty("this.id")); // join to owning entity subselect.setProjection(Projections.max("validFrom")); // we are only interested in the maximum validFrom Conjunction resultCriterion = Restrictions.conjunction(); resultCriterion.add(Restrictions.ilike(property, value)); // I have other Restrictions as well resultCriterion.add(Property.forName("validFrom").eq(subselect)); // this fails when validFrom and the subselect return NULL return resultCriterion; It works ok so far, but the restriction on the last line before the return statement is false when validFrom and subselect result in NULL. What I need is a version which handles this case as true. Possibly by applying a NVL or coalesce or similar. How do I do this?

    Read the article

  • Richfaces a4j achtionparam set null value

    - by Jurgen H
    I am trying to reset some values in a form using the a4j:actionParam tag. But it seams that null values never arrive in the target bean. The converter receives it correctly, returns null, but it is never set in the bean. The target is to fill in the start and endDate for different predefined values (last week, last month etc). For the "This week" value, the endDate must be reset to null. <rich:menuItem value="Last week"> <a4j:support event="onclick" reRender="criteriaStartCalendar,criteriaEndCalendar"> <a4j:actionparam name="startDate" value="#{dateBean.lastWeekStart}" assignTo="#{targetBean.startDate}" /> <a4j:actionparam name="endDate" value="#{dateBean.lastWeekEnd}" assignTo="#{targetBean.endDate}" /> </a4j:support> </rich:menuItem>

    Read the article

  • Querying MySQL with CodeIgniter, selecting rows where field is NULL

    - by rebellion
    I'm using CodeIgniter's Active Record class to query the MySQL database. I need to select the rows in a table where a field is not set to NULL: $this->db->where('archived !=', 'NULL'); $q = $this->db->get('projects'); That only returns this query: SELECT * FROM projects WHERE archived != 'NULL'; The archived field is a DATE field. Is there a better way to solve this? I know I can just write the query myself, but I wan't to stick with the Active Record throughout my code.

    Read the article

  • DB4o Linq query - How to check for null strings

    - by Dave
    Hey there - simple query: var q = (from SomeObject o in container where o.SomeInt > 8 && o.SomeString != null //Null Ref here select o; I always get a null reference exception. If I use String.IsNullOrEmpty(o.SomeString) the query takes about 100 times as long, as if I use && o.SomeString != "" (which is way faster, but obviously not correct). I'm guessing because DB4o needs to activate the objects, in order to pass them in to the IsNullOrEmpty call, and can't use the indexes. My question is, what's a better way to check for nulls in this situation? Is there something like: mystring != Db4o.DBNull.Value, or something? Cheers, Dave

    Read the article

  • IS NULL doesn't work as expected in SQL Server 2000 with no Service Pack on it

    - by user306825
    The following batch executed on different instances of SQL Server 2000 illustrates the problem. select @@version create table a (a int) create table b (b int) insert into a(a) values (1) insert into a(a) values (2) insert into a(a) values (3) insert into b(b) values (1) insert into b(b) values (2) select * from a left outer join (select 1 as test, b from b) as j on j.b = a.a where j.test IS NULL drop table a drop table b Output 1: Microsoft SQL Server 2000 - 8.00.194 (Intel X86) Aug 6 2000 00:57:48 Copyright (c) 1988-2000 Microsoft Corporation Developer Edition on Windows NT 6.1 (Build 7600: ) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b ----------- ----------- ----------- (0 row(s) affected) Output 2: Microsoft SQL Server 2000 - 8.00.2039 (Intel X86) May 3 2005 23:18:38 Copyright (c) 1988-2003 Microsoft Corporation Developer Edition on Windows NT 5.2 (Build 3790: Service Pack 2) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b ----------- ----------- ----------- 3 NULL NULL (1 row(s) affected) If someone encounters the same problem - make sure you have the SP installed!

    Read the article

  • IS NULL doesn't work as expected in MSSQL 2000 with no Service Pack on it

    - by user306825
    The following batch executed on different instances of mssql 2000 illustrates the problem. select @@version create table a (a int) create table b (b int) insert into a(a) values (1) insert into a(a) values (2) insert into a(a) values (3) insert into b(b) values (1) insert into b(b) values (2) select * from a left outer join (select 1 as test, b from b) as j on j.b = a.a where j.test IS NULL drop table a drop table b Output 1: Microsoft SQL Server 2000 - 8.00.194 (Intel X86) Aug 6 2000 00:57:48 Copyright (c) 1988-2000 Microsoft Corporation Developer Edition on Windows NT 6.1 (Build 7600: ) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b (0 row(s) affected) Output 2: Microsoft SQL Server 2000 - 8.00.2039 (Intel X86) May 3 2005 23:18:38 Copyright (c) 1988-2003 Microsoft Corporation Developer Edition on Windows NT 5.2 (Build 3790: Service Pack 2) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b 3 NULL NULL (1 row(s) affected) If someone encounters the same problem - make sure you have the SP installed!

    Read the article

  • Map null column as 0 in a legacy database (JPA)

    - by Indrek
    Using Play! framework and it's JPASupport class I have run into a problem with a legacy database. I have the following class: @Entity @Table(name="product_catalog") public class ProductCatalog extends JPASupport { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) public Integer product_catalog; @OneToOne @JoinColumn(name="upper_catalog") public ProductCatalog upper_catalog; public String name; } Some product catalogs don't have an upper catalog, and this is referenced as 0 in a legacy database. If I supply the upper_catalog as NULL, then expectedly JPA inserts a NULL value to that database column. How could I force the null values to be 0 when writing to the database and the other way around when reading from the database?

    Read the article

  • Accommodating null values in a list?

    - by h259bws
    Hi, I'm new to Java and Groovy and am running into trouble with the following Groovy script. I created this whittled down version of a larger script to facilitate debugging. The script is iterating through a list trying to calc a running total of the values of all objects in the list. Some or all of these objects' values may be null. Script import org.apache.commons.lang.math.NumberUtils class Field { def name def value } def fields = [ new Field(name:'Annuities %', value:75), new Field(name:'Other %', value:null), ] //def totalFunding = fields.inject(0) {int total, Field myField - // total + NumberUtils.toInt(myField.value,0) as Integer def totalFunding = fields.inject(0) {int total, Field myField - total + myField?.value as Integer } It gets this error: Exception thrown: java.lang.NullPointerException java.lang.NullPointerException at Script3$_run_closure1.doCall(Script3:15) at Script3.run(Script3:14) What is the correct way to accomodate null values? Thanks, Betsy

    Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >