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• Results from two queries at once in sqlite?

  - by SF.

  I'm currently trying to optimize the sluggish process of retrieving a page of log entries from the SQLite database. I noticed I almost always retrieve next entries along with count of available entries: SELECT time, level, type, text FROM Logs WHERE level IN (%s) ORDER BY time DESC, id DESC LIMIT LOG_REQ_LINES OFFSET %d* LOG_REQ_LINES ; together with total count of records that can match current query: SELECT count(*) FROM Logs WHERE level IN (%s); (for a display "page n of m") I wonder, if I could concatenate the two queries, and ask them both in one sqlite3_exec() simply concatenating the query string. How should my callback function look then? Can I distinguish between the different types of data by argc? What other optimizations would you suggest?

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• How to ensure consistency of enums in Java serialization?

  - by Uri

  When I serialize an object, I can use the serialVersionUID mechanism at the class level to ensure the compatibility of the two types. However, what happens when I serialize fields of enum values? Is there a way to ensure that the enum type has not been manipulated between serialization and deserialization? Suppose that I have an enum like OperationResult {SUCCESS, FAIL}, and a field called "result" in an object that is being serialized. How do I ensure, when the object is deserialized, that result is still correct even if someone maliciously reversed the two? (Suppose the enum is declared elsewhere as a static enum) I am wondering out of curiosity - I use jar-level authentication to prevent manipulation.

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• Python Class Variables Question

  - by zyq524

  I have some doubt about python's class variables. As my understanding, if I define a class variable, which is declared outside the init() function, this variable will create only once as a static variable in C++. This seems right for some python types, for instance, dict and list type, but for those base type, e.g. int,float, is not the same. For example: class A: dict1={} list1=list() int1=3 def add_stuff(self, k, v): self.dict1[k]=v self.list1.append(k) self.int1=k def print_stuff(self): print self.dict1,self.list1,self.int1 a1 = A() a1.add_stuff(1, 2) a1.print_stuff() a2=A() a2.print_stuff() The output is: {1: 2} [1] 1 {1: 2} [1] 3 I understand the results of dict1 and list1, but why does int1 behavior different?

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• Methods specific only to an instance? What are they called in Ruby?

  - by daremarkovic

  I know there are "instance methods", "class methods" but what are these types of methods called, for eg: s1 = "This is my STRING!" def s1.m1 downcase end p s1 # => "This is my STRING!" p s1.m1 # => "this is my string!" What type of method is the "m1" method called on the s1 "instance" of the "string" class? It's really weird because I didn't know this was possible at all if I try: s2 = "This is ANOTHER string" s2.m1 # => Won't work! Which kind of makes sense, but not sure why defining methods like m1 on instances on a class are useful at all.

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• No mapping for LONGVARCHAR in Hibernate 3.2

  - by jimbokun

  I am running Hibernate 3.2.0 with MySQL 5.1. After updating the group_concat_max_len in MySQL (because of a group_concat query that was exceeding the default value), I got the following exception when executing a SQLQuery with a group_concat clause: "No Dialect mapping for JDBC type: -1" -1 is the java.sql.Types value for LONGVARCHAR. Evidently, increasing the group_concat_max_len value causes calls to group_concat to return a LONGVARCHAR value. This appears to be an instance of this bug: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3892 I guess there is a fix for this issue in Hibernate 3.5, but that is still a development version, so I am hesitant to put it into production, and don't know if it would cause issues for other parts of my code base. I could also just use JDBC queries, but then I have to replace every instance of a SQLQuery with a group_concat clause. Any other suggestions?

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• How to align C++ class member names in one column in emacs ?

  - by KotBerbelot

  I would like to align all C++ class member names ( do not confuse with member types ) in one column. Lets look at the example of what we have at entrance: class Foo { public: void method1( ); int method2( ); const Bar * method3( ) const; protected: float m_member; }; and this is what we would like to have at the end: class Foo { public: void method1( ); int method2( ); const Bar * method3( ) const; protected: float m_member; }; So the longest member type declaration defines the column to which class member names will be aligned. How can i perform such transformation in emacs ?

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• How could my code compliled correctly without necessary headers?

  - by ZhengZhiren

  I use the functions fork(),exec()... But how can this program compiled without including some extra headers(like sys/types.h, sys/wait.h). I use ubuntu 10.04 with gcc version 4.4.3 #include <stdio.h> #include <stdlib.h> int main() { pid_t pid; printf("before fork\n"); pid = fork(); if(pid == 0) { /*child*/ if(execvp("./cpuid", NULL)) { printf("error\n"); exit(0); } } else { if(wait(NULL) != -1) { printf("ok\n"); } } return 0; }

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• returning null or throwing an exception?

  - by MoKi

  I have the following types: typedef QPair < QTime , QTime > CalculatedTimeSlotRange; typedef QList < CalculatedTimeSlotRange > CalculatedTimeSlotRangeList; typedef QHash < quint8 , CalculatedTimeSlotRangeList > TimeSlotsTable; I have a function like the following: const CalculatedTimeSlotRangeList* TimeSlots::getCalculatedTimeSlotRangeList(const quint8 id) const { QHashIterator<quint8,CalculatedTimeSlotRangeList> it(mTimeSlotsTable); while (it.hasNext()) { it.next(); if(it.key() == id) { return &it.value(); } } return NULL; } as you can see my function returns a null if it fails to find a key that matches id. Is this correct? or should I just throw an exception if the key does not exist? how should i throw an exception for this situation?

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• Mapping to a different view based on child type

  - by Ryan Burnham

  So i have a situation where i have common base type but i need to map to a different view based on the child type. It looks like i can use a generic mapping class to handle the inheritance http://geekswithblogs.net/nharrison/archive/2010/07/09/inheriting-a-class-map-in-fluent-nhibernate.aspx But how can i conditionally map to a different view based on the child type? I see an EntityType property but it says its obsolete and will be made private in the next version. As an example i have a base class of ContactInfo is standard between contact types but the values come from different places depending on the contact type, this I'll handle through the sql view.

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• Using template specialization in C++

  - by user550413

  How can I write a function using template specialization that has 2 different input types and an output type: template <class input1, class input2, class output> and return the sum of the 2 numbers (integers/doubles). However, if I get 2 integers I want to return an integer type but for any other combinations of integer and double I'll always return double. I am trying to do that without using directly the '+' operator but having the next functions instead: double add_double_double(double a, double b) {return (a+b);} double add_int_double(int a, double b) {return ((double)(a)+b);} int add_int_int(int a, int b) {return (a+b);}

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• Customers and suppliers database design issue

  - by hectorsq

  I am developing a web application in which I will have customers and suppliers. Initially I thought on using a Customers table and a Suppliers table. Then when I was thinking on bank transactions, I noticed that each transaction needs to refer to a customer or a supplier, so I thought on using a single table named Business in which I will save both customers and suppliers. If I use Customers and Suppliers tables when I want to list the bank transactions I will have to search in both tables to get the company name. If I use a Businesses table I will have to use a business type column, and have the union of possible fields for all businesses types. Any suggestions on the design?

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• Is it possible to use inheritance in this situation? (Java)

  - by they changed my name

  I have ClassA and ClassB, with ClassA being the superclass. ClassA uses NodeA, ClassB uses NodeB. First problem: method parameters. ClassB needs NodeB types, but I can't cast from the subclass to the superclass. That means I can't set properties which are unique to NodeB's. Second problem: When I need to add nodes toClassB, I have to instantiate a new NodeB. But, I can't do this in the superclass, so I'd have to rewrite the insertion to use NodeB. Is there a way around it or am I gonna have to rewrite the whole thing?

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• Separating MySQL SELECT statement based on data in a column

  - by NightMICU

  Hi everyone, I need to retrieve data (vehicle details, in this case) from a MySQL table tabled and then loop through the results to generate separate lists for each category of vehicle. Is there a simple way to do this without having to have a SELECT statement for each type of vehicle? If I were just doing this for one category, I would use the following: <?php $sql = "SELECT * FROM apparatus WHERE vehicleType = 'Support'; $getSQL = mysql_query($sql); ?> <ul> <?php while ($vehicleData = mysql_fetch_assoc($getSQL)) {?> <li><?php echo $vehicleData['name'];?></li> <?php } ?> </ul> ..etc. Need to do this for four different types of vehicles. Thanks!

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• In a C++ template, is it allowed to return an object with spesific type parameters?

  - by nieldw

  When I've got a template with certain type parameters, is it allowed for a function to return an object of this same template, but with different types? In other words, is the following allowed? template<class edgeDecor, class vertexDecor, bool dir> Graph<edgeDecor,int,dir> Graph<edgeDecor,vertexDecor,dir>::Dijkstra(vertex s, bool print = false) const { /* Construct new Graph with apropriate decorators */ Graph<edgeDecor,int,dir> span = new Graph<edgeDecor,int,dir>(); /* ... */ return span; }; If this is not allowed, how can I accomplish the same kind of thing?

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• Accessing object's method within string

  - by Wild One

  Recently I was reading php documentation and found interesting note in string section: Functions, method calls, static class variables, and class constants inside {$} work since PHP 5. However, the value accessed will be interpreted as the name of a variable in the scope in which the string is defined. Using single curly braces ({}) will not work for accessing the return values of functions or methods or the values of class constants or static class variables. See www.php.net/manual/en/language.types.string.php It says, that I can't use curly syntax to get value returned by object's method call. Is it a mistake in manual or I misunderstood it, because I tried the following code and it works just fine: <?php class HelloWorld { public static function hello() { echo 'hello'; } } $a = new HelloWorld(); echo "{$a->hello()} world";

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• Fractional Calculator in Java

  - by user2888881

  I am trying to create a fractional calculator in Java with inputs of mixed fractions, proper fractions, improper fractions or integers. It should include the four basic operators as well. The program should be set up as a loop where it is continuous until the user types "quit". I have coded the beginning loop but have no idea where to go from there. Please help, I am a beginner and would really appreciate it. Thank you again. This is what I have so far: import java.util.*; public class FractionCalculator { private static Scanner input; public static void main(String[] args) { input = new Scanner(System.in); String x = "quit"; System.out.println("Enter a fraction"); while (true) { String y = input.next(); if (y.equals(x)) { break; } } } }

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• Java: How to get Unicode name of a character (or its type category)?

  - by java.is.for.desktop

  Hello, everyone! The Character class in Java defines methods which check a given char argument for equality with certain Unicode chars or for belonging to some type category. These chars and type categories are named. As stated in given javadoc, examples for named chars are HORIZONTAL TABULATION, FORM FEED, ...; example for named type categories are SPACE_SEPARATOR, PARAGRAPH_SEPARATOR, ... However, being byte or int values instead of enums, the name of these types are "hidden" at runtime. So, is there a possibility to get characters' and/or type categories' names at runtime?

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• Recordset Update errors when updating sql_variant field

  - by Stephen Nutt

  I'm using C++ and ADO to add data to a SQL Server 2005 database. When calling the Recordset Update method for a sql_variant column I'm getting the error DB_E_ERRORSOCCURRED and the error message Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done. If the value I'm adding is NULL all works fine and all values going to the fields that are not sql_variant types work. Does anyone know what I might be doing wrong? Thanks [Edit] I have some more information. The value we are storing is the empty string - ADO appears to want to store this in the sql_variant as a nchar(0), which of course is not a valid SQL data type. Is there a way to get an empty string in a sql_variant using the ADO batch commands?

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• how to get key value of array with curl (php)

  - by Vierri

  Hello I want to make use of an API but it print alot of info and i don't know how i can get a few key values of the array. <?php $query = "SELECT * FROM kvk WHERE adres='Wit-geellaan 158'"; $host = "http://api.openkvk.nl/php/"; $url = $host ."/". rawurlencode($query); $curl = curl_init(); curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1); curl_setopt($curl, CURLOPT_URL, $url); curl_setopt($curl, CURLOPT_HEADER, 0); curl_exec($curl); curl_close($curl); ?> Is my php script and it shows array(array("RESULT"=>array("TYPES"=>array("int","bigint","varchar","varchar","varchar","varchar","varchar","int","int","smallint","smallint","int"),"HEADER"=>array("id","kvk","bedrijfsnaam","adres","postcode","plaats","type","kvks","sub","bedrijfsnaam_size","adres_size","verhuisd"),"ROWS"=>array(array("1303095","271242250000","Schoonmaakbedrijf Regio","Wit-geellaan 158","2718CK","Zoetermeer","Hoofdvestiging","27124225","0","23","16","0"))))) Thanks in advance Greetings, Vierri

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• Composite pattern in C++ problem

  - by annouk

  Hello! I have to work with an application in C++ similar to a phone book: the class Agenda with an STL list of Contacts.Regarding the contacts hierarchy,there is a base-class named Contact(an abstract one),and the derived classes Friend and Acquaintance(the types of contact). These classes have,for instance, a virtual method called getName,which returns the name of the contact. Now I must implement the Composite pattern by adding another type of contact,Company(being derived from Contact),which also contains a collection of Contacts(an STL list as well),that can be either of the "leaf" type(Friends or Acquaintances),or they can be Companies as well. Therefore,Company is the Compound type. The question is: how and where can I implement an STL find_if to search the contact with a given name(via getName function or suggest me smth else) both among the "leaf"-type Contact and inside the Company collection? In other words,how do I traverse the tree in order to find possible matches there too,using an uniform function definition? I hope I was pretty clear...

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• extending Bash tab completion: how to handle paths / partial commands?

  - by Rawing

  I've added tab completion for my program to bash. It works quite well, but I don't know how to handle partial completion of words. Example: the user types ./program /home/user/De and presses TAB. This is then completed to ./program /home/user/Desktop/ , but there's now a trailing whitespace after 'Desktop/', which is not what I want. Basically, I need a way of preventing bash from adding whitespace after the completed word. I don't want to use bash's completion for paths.

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• How does ‘Servers’ view work underlying in Eclipse?

  - by Michael Lu

  ‘Servers’ is built-in view in Eclipse. We could integrate jee server into Eclipse easily. It could start/stop server both in normal and debug modes. Moreover, we could even set timeout and deployment path, things like that. Various types of server tomcat, jboss, websphere are supported, no intrusive to server. I am just curious about how these cool things happen behind the scene. The complete mechanism is large and complex, so I just want to know general mechanism about it, an article also could be fine for me. Thank you!

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• C++ enforce conditions on inherited classes

  - by user231536

  I would like to define an abstract base class X and enforce the following: a) every concrete class Y that inherits from X define a constructor Y(int x) b) it should be possible to test whether two Y objects are equal. For a, one not very good solution is to put a pure virtual fromInt method in X which concrete class will have to define. But I cannot enforce construction. For b), I cannot seem to use a pure virtual method in X bool operator == (const X& other) const =0; because in overridden classes this remains undefined. It is not enough to define bool operator == (const Y& other) const { //stuff} because the types don't match. How do I solve these problems?

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• Setting variable to value of form [drupal 6]

  - by N Schleder

  I have this form $form['title'] = array( '#type' => 'textfield', '#title' => t('Title of Notice'), '#description' => t('Use_underscores_as_spaces'), '#size' => 30, // '#required' => TRUE ); and I want whatever the user types in to be the value of $test I've tried $test = $form['title']; which gives me $test = array also I've tried $test = current($form['title']); which gives me $test = textfield $form['values']['title'] doesn't work dont know what else to try

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• submit button on html to output result on same page

  - by amateur

  Hi, Although this seems like something very basic, but no matter what I tried I couldn't get my head around it. Basically I want a html form where a user types in their ID number in an input text box and when they hit the submit button it displays their email address which is their company ID number @ company.com, such as below <form action=""> ID Number: <input type="text" name="idnumber" /><br/> <input type="submit" value="Whats my email address" /> </form> <p>Your email address is 'idnumber'@email.com</p> Can this even be done using html or would I need to use Javascript or PHP for it? Thanks

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