Tutorial by Examples: t

Compound assignment operators

SQL Server 2008 R2 Supported compound operators: += Add and assign -= Subtract and assign *= Multiply and assign /= Divide and assign %= Modulo and assign &= Bitwise AND and assign ^= Bitwise XOR and assign |= Bitwise OR and assign Example usage: DECLARE @test INT = 42; SET @test...

Static class members

A class is also allowed to have static members, which can be either variables or functions. These are considered to be in the class' scope, but aren't treated as normal members; they have static storage duration (they exist from the start of the program to the end), aren't tied to a particular inst...

Join parent and child JSON entities using CROSS APPLY OPENJSON

Join parent objects with their child entities, for example we want a relational table of each person and their hobbies DECLARE @json nvarchar(1000) = N'[ { "id":1, "user":{"name":"John"}, "hobbies":[ {...

Programmatically adding a metadata endpoint to a service

When you also want to expose metadata without a config file you can build on the example programmatically creating a ServiceHost: public ConsoleHost() { mHost = new ServiceHost(typeof(Example), new Uri("http://localhost:8000/Example"), new Uri("net.tcp://9000/Example")); ...

Place allocation and cleanup code next to each other

Scope guards allow executing statements at certain conditions if the current block is left. import core.stdc.stdlib; void main() { int* p = cast(int*)malloc(int.sizeof); scope(exit) free(p); }

Multiple, nested scopes

import std.stdio; void main() { writeln("<html>"); scope(exit) writeln("</html>"); { writeln("\t<head>"); scope(exit) writeln("\t</head>"); "\t\t<title>%s</title>".write...

Unit Testing Promises with Mocha, Sinon, Chai and Proxyquire

Here we have a simple class to be tested that returns a Promise based on the results of an external ResponseProcessor that takes time to execute. For simplicty we'll assume that the processResponse method won't ever fail. import {processResponse} from '../utils/response_processor'; const ping =...

Global imports

import std.stdio; void main() { writeln("Hello World!"); } Multiple imports can either be specified in the same line, separated with a comma or in a new line. import std.stdio, std.math; import std.datetime; void main() { writeln("2^4: ", pow(2, 4)); writ...

Selective imports

Selective imports can help to cleanup the namespace and speed-up the compile-time even more, because the compiler only needs to parse the specific, selected functions. import std.stdio: writeln; void main() { writeln("Hello world"); }

Local imports

You can also import symbols in any scope, the import will only be looked up when the scope is needed (i.e. compiled) and the imported names will only be exposed in the imported scope. Most commonly the scope for local imports are functions, structs and classes. void main() { import std.stdio:...

Public imports

Modules can be exposed to other modules with public imports. public import std.math; // only exports the symbol 'pow' public import std.math : pow;

Renamed imports

A local name for an import can be given, through which all references to the module's symbols must be qualified with: import io = std.stdio; void main() { io.writeln("Hello world"); std.stdio.writeln("hello!"); // error, std is undefined writeln("hello!&qu...

Renamed and selective imports

Selective imports may also be renamed. void main() { import std.stdio : fooln = writeln; fooln("Hello world"); }

Module declaration

Modules have a one-to-one correspondence with source files. The module name is, by default, the file name with the path and extension stripped off, and can be set explicitly with the module declaration. The ModuleDeclaration sets the name of the module and what package it belongs to. If absent, the...

Using move semantics on containers

You can move a container instead of copying it: void print(const std::vector<int>& vec) { for (auto&& val : vec) { std::cout << val << ", "; } std::cout << std::endl; } int main() { // initialize vec1 with 1, 2, 3, 4 and...

Re-use a moved object

You can re-use a moved object: void consumingFunction(std::vector<int> vec) { // Some operations } int main() { // initialize vec with 1, 2, 3, 4 std::vector<int> vec{1, 2, 3, 4}; // Send the vector by move consumingFunction(std::move(vec)); // Here...

Find all matches

Using using System.Text.RegularExpressions; Code static void Main(string[] args) { string input = "Carrot Banana Apple Cherry Clementine Grape"; // Find words that start with uppercase 'C' string pattern = @"\bC\w*\b"; MatchCollection matches = Regex.M...

Grant and Revoke Privileges.

Suppose, that we have three users : The Administrator of the database > admin The application with a full access for her data > read_write The read only access > read_only --ACCESS DB REVOKE CONNECT ON DATABASE nova FROM PUBLIC; GRANT CONNECT ON DATABASE nova TO user; With th...

How to use the strftime method

Converting a time to a string is a pretty common thing to do in Ruby. strftime is the method one would use to convert time to a string. Here are some examples: Time.now.strftime("%Y-%m-d %H:%M:S") #=> "2016-07-27 08:45:42" This can be simplified even further Time.now.str...

Rudimentary cursor syntax

A simple cursor syntax, operating on a few example test rows: /* Prepare test data */ DECLARE @test_table TABLE ( Id INT, Val VARCHAR(100) ); INSERT INTO @test_table(Id, Val) VALUES (1, 'Foo'), (2, 'Bar'), (3, 'Baz'); /* Test data prepared */ /* Iterator variabl...

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