Sometimes when tables are used mostly (or only) for reads, indexing does not help anymore and every little bit counts, one might use selects without LOCK to improve performance.
SQL Server
SELECT * FROM TableName WITH (nolock)
MySQL
SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;...
Sometimes one wants to capture the records that have just been updated.
CREATE TABLE #TempUpdated(ID INT)
Update TableName SET Col1 = 42
OUTPUT inserted.ID INTO #TempUpdated
WHERE Id > 50
The Kernel#require method will load files only once (several calls to require will result in the code in that file being evaluated only once). It will search your ruby $LOAD_PATH to find the required file if the parameter is not an absolute path. Extensions like .rb, .so, .o or .dll are optional. Re...
The method Kernel#autoload registers filename to be loaded (using Kernel::require) the first time that module (which may be a String or a symbol) is accessed.
autoload :MyModule, '/usr/local/lib/modules/my_module.rb'
The method Kernel#autoload? returns filename to be loaded if name is registere...
When files are not available, the require family will throw a LoadError. This is an example which illustrates loading optional modules only if they exist.
module TidBits
@@unavailableModules = []
[
{ name: 'CoreExtend', file: 'core_extend/lib/core_extend' } \
, { name: 'Fs' ...
The Kernel#load method will evaluate the code in the given file. The search path will be constructed as with require. It will re-evaluate that code on every subsequent call unlike require. There is no load_relative.
load `somefile`
You can use any ruby technique to dynamically create a list of files to load. Illustration of globbing for files starting with test, loaded in alphabetical order.
Dir[ "#{ __dir__ }**/test*.rb" ) ].sort.each do |source|
require_relative source
end
To get records having any of the given ids
select *
from products
where id in (1,8,3)
The query above is equal to
select *
from products
where id = 1
or id = 8
or id = 3
This function returns the floating-point remainder of the division of x/y. The returned value has the same sign as x.
#include <math.h> /* for fmod() */
#include <stdio.h> /* for printf() */
int main(void)
{
double x = 10.0;
double y = 5.1;
double modulus = fmod(x,...
Requirements: Docker can be installed on any Linux with a kernel of at least version 3.10. Docker is supported on the following 64-bit versions of Ubuntu Linux:
Ubuntu Xenial 16.04 (LTS)
Ubuntu Wily 15.10
Ubuntu Trusty 14.04 (LTS)
Ubuntu Precise 12.04 (LTS)
Easy Installation
Note: Installi...
Python classes support properties, which look like regular object variables, but with the possibility of attaching custom behavior and documentation.
class MyClass(object):
def __init__(self):
self._my_string = ""
@property
def string(self):
"&...
Custom sigils can be made by creating a method sigil_X where X is the letter you want to use (this can only be a single letter).
defmodule Sigils do
def sigil_j(string, options) do
# Split on the letter p, or do something more useful
String.split string, "p"
end
# Use t...
Ensure you have the latest nodeJS LTS installed
Open command prompt and type $ npm install -g nativescript
In the command prompt type $ @powershell -NoProfile -ExecutionPolicy Bypass -Command "iex ((new-object net.webclient).DownloadString('https://www.nativescript.org/setup/win'))" - ...
Visual Studio Code is an open-source and feature-rich code editor from Microsoft. To set it up it for NativeScript development, open the Command Palette (F1 or ⌘+Shift+P) and type ext install NativeScript.
Once the NativeScript extension is installed, the debugger should allow you to set breakpoint...
In the following example, the greet function inside Greeter module is run in a separate process:
defmodule Greeter do
def greet do
IO.puts "Hello programmer!"
end
end
iex> spawn(Greeter, :greet, [])
Hello
#PID<0.122.0>
Here #PID<0.122.0> is the ...
Named Functions
defmodule Math do
# one way
def add(a, b) do
a + b
end
# another way
def subtract(a, b), do: a - b
end
iex> Math.add(2, 3)
5
:ok
iex> Math.subtract(5, 2)
3
:ok
Private Functions
defmodule Math do
def sum(a, b) do
a...
Elixir matches a function call to its body based on the value of its arguments.
defmodule Math do
def factorial(0): do: 1
def factorial(n): do: n * factorial(n - 1)
end
Here, factorial of positive numbers matches the second clause, while factorial(0) matches the first. (ignoring negat...
C99
Type Declaration
A structure with at least one member may additionally contain a single array member of unspecified length at the end of the structure. This is called a flexible array member:
struct ex1
{
size_t foo;
int flex[];
};
struct ex2_header
{
int foo;
char...
