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• using dummy row with NOT NULL to solve DEFAUT NULL

  - by Tony38

  I know having DEFAULT NULLS is not a good practice but I have many optional lookup values which are FK in the system so to solve this issue here is what i am doing: I use NOT NULL for every FK / lookup valve field. I have the first row in every table which is PK id = 1 as a dummy row with just "none" in all the columns. this way I can use NOT NULL…

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• rails belongs_to sql statement using NULL id

  - by Team Pannous

  When paginating through our Phrase table it takes very long to return the results. In the sql logs we see many sql requests which don't make sense to us: Phrase Load (7.4ms) SELECT "phrases".* FROM "phrases" WHERE "phrases"."id" IS NULL LIMIT 1 User Load (0.4ms) SELECT "users".* FROM "users" WHERE "users"."id" IS NULL LIMIT 1 These add up…

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• Is there an "opposite" to the null coalescing operator? (…in any language?)

  - by Jay

  null coalescing translates roughly to return x, unless it is null, in which case return y I often need return null if x is null, otherwise return x.y I can use return x == null ? null : x.y; Not bad, but that null in the middle always bothers me -- it seems superfluous. I'd prefer something like return x :: x.y;, where what follows the :: is…

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• A null value should be considered as 0 when addition of it is done with decimal value.

  - by Harikrishna

  There are three column in the datatable A,B and C. Now each column is type of decimal. Now I am doing like dt.Columns["A"].Expression="B+C"; to make addition of Column B's record and column C's record. Now if there is any value of B or C is null then addition of B and C will be null like B's value is 3 and C's value is null for first row then…

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• Can PCRE regex match a null character?

  - by Keng

  I have a text source with nulls in it and I need to pull them out along with my regex pattern. Can regex even match a null character? I only realized I had them when my pattern refused to match and when I pasted it into Notepad++ it showed all the null characters.

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• Mysql Left Join Null Result

  - by Ozzy

  I have this query SELECT articles.*, users.username AS `user` FROM `articles` LEFT JOIN `users` ON articles.user_id = users.id ORDER BY articles.timestamp Basically it returns the list of articles and the username that the article is associated to. Now if there is no entry in the users table for a particular user id, the…

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• Setting a null value in JSF

  - by DD

  I'm trying to set a property to null in JSF but it is interpretting null as a String. Is there a way to do this:

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• difference between "=null" and "is null" in sql server 2008

  - by user329820

  Hi I asked the same question in this forum but I want to know that is there any differnce between "=null" and "is null" in sql server 2008? thanks

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• HashMap null key

  - by subhashis

  HashMap allows one null key and any number of null values. what is the use of it?

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• Can a constructor return a NULL value?

  - by Sanctus2099

  I know constructors don't "return" anything but for instance if I call CMyClass *object = new CMyClass() is there any way to make object to be NULL if the constructor fails? In my case I have some images that have to be loaded and if the file reading fails I'd like it to return null. Is there any way to do that? Thanks in advance.

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• Checking for a null int value from a Java ResultSet

  - by ian_scho_es

  In Java I'm trying to test for a null value, from a ResultSet, where the column is being cast to a primitive int type. int iVal; ResultSet rs = magicallyAppearingStmt.executeQuery(query); if (rs.next()) { if (rs.getObject("ID_PARENT") != null && !rs.wasNull()) { iVal = rs.getInt("ID_PARENT"); } } From the code…

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• mysql showing null values for group by statements

  - by khelll

  I'm doing select sum(clicks), date from stats group by date;, however when the sum is null for some date, the whole row is discarded, I want to see: | null | some_date |, how to do so? Cheers,

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• what is the difference between null != object and object!=null

  - by rozer

  Please guide me. what is the difference between null != object and object!=null same for "".equal("something") and "something".equals("") which one is good for processing.

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• Is null a class in java?

  - by Somerandomeguy

  According to, http://www.freshvanilla.org:8080/display/www/Java+Interview+Questions Under, Which class is the superclass of every class? null seems to be the answer. I found that new Object().getClass().getSuperClass() verifies the answer as correct. But can null be considered a class? I see all primitive data…

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• what is the value of NULL in sqlserver ?

  - by Anish

  Hi, I know NULL is not zero...nor it is empty string.But then what is the value of NULL...which the system keeps, to identify it?

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• Android ListView: getTag() returns null

  - by TianDong

  Hallo all, I have a ListView which contains a Button in each line. The following code is part of the getView() Method public View getView(final int position, View convertView, ViewGroup parent) { View row = convertView; TextView tv; Button saveA_button; EditText edittext; …

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• Problem using void pointer as a function argument

  - by Nazgulled

  Hi, I can't understand this result... The code: void foo(void * key, size_t key_sz) { HashItem *item = malloc(sizeof(HashItem)); printf("[%d]\n", (int)key); ... item->key = malloc(key_sz); memcpy(item->key, key, key_sz); } void bar(int num) { foo(&num, sizeof(int)); } …

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• C - Complicated pointer declarations - help understanding

  - by Emmel

  In my burgeoning new self-education in the C language, I've come across a set of declarations that I do not understand how to read. I'd love for someone to break these down. I'll explain at the bottom where I got these examples from. 1. char (*(*x())[])() "x: function returning pointer to array[] of…

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• C: Extrapolating type from void pointer

  - by Yktula

  Say a function takes a void pointer as an argument, like so: int func(void *p); How can we determine or guess the type of what p is pointing to?

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• Function pointer demo

  - by AKN

  Hi, Check the below code void functionptrdemo() { typedef int *(funcPtr) (int,int); funcPtr ptr; ptr = add; //IS THIS CORRECT? (*ptr)(2,3); } In the place where I try to assign a function to function ptr with same function signature, it shows a compilation error as error C2659: '=' : function as…

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• Erlang ODBC parameter query with null parameters

  - by Schlomer

  Is it possible to pass null values to parameter queries? For example Sql = "insert into TableX values (?,?)". Params = [{sql_integer, [Val1]}, {sql_float, [Val2]}]. % Val2 may be a float, or it may be the atom, undefined odbc:param_query(OdbcRef, Sql, Params). Now, of course odbc:param_query/3…

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• Assign C++ instance method to a global-function-pointer ?

  - by umanga

  Greetings, My project structure is as follows: \- base (C static library) callbacks.h callbacks.c paint_node.c . . * libBase.a \-app (C++ application) main.cpp In C library 'base' , I have declared global-function-pointer as: in singleheader file …

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• Passing a pointer to a function that doesn't match the requirements of the formal parameter

  - by Andreas Grech

  int valid (int x, int y) { return x + y; } int invalid (int x) { return x; } int func (int *f (int, int), int x, int y) { //f is a pointer to a function taking 2 ints and returning an int return f(x, y); } int main () { int val = func(valid, 1, 2), inval =…

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• Why can operator-> be overloaded manually?

  - by FredOverflow

  Wouldn't it make sense if p->m was just syntactic sugar for (*p).m? Essentially, every operator-> that I have ever written could have been implemented as follows: Foo::Foo* operator->() { return &**this; } Is there any case where I would want p->m to mean something…

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• C++: How do I pass a function(without knowing its parameters) to another function?

  - by Ninja

  Hi all. I'm trying to create a function that will store and repeat another function given as a parameter for a specific amount of time or repeats given. But when you want to pass a function as a parameter you have to know all of its parameters before hand. How would I do if I wanted to…

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