Tutorial by Examples: p

While it's good practice to use a Unix based operating system (ex. Linux or BSD) as a production server you can easily install PostgreSQL on Windows (hopefully only as a development server). Download the Windows installation binaries from EnterpriseDB: http://www.enterprisedb.com/products-services-...

Assume you have a custom file you want to create an importer for. It could be an .xls file or whatever. In this case we're going to use a JSON file because it's easy but we're going to pick a custom extension to make it easy to tell which files are ours? Let's assume the format of the JSON file is ...

The "right-left" rule is a completely regular rule for deciphering C declarations. It can also be useful in creating them. Read the symbols as you encounter them in the declaration... * as "pointer to" - always on the left side [] as "array of" ...

WeakMap object allows you to store key/value pairs. The difference from Map is that keys must be objects and are weakly referenced. This means that if there aren't any other strong references to the key, the element in WeakMap can be removed by garbage collector. WeakMap constructor has an optional...

In order to compile docker its recommended you have at least 2 GB RAM. Even with that it fails sometimes so its better to go for 4GB instead. make sure git and make is installed sudo apt-get install make git-core -y install a new kernel (at least 4.2) sudo apt-get install linux-generic...

# create docker container export cid=$(docker run -d --security-opt seccomp:unconfined busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done') # container is started and prints a number every second # display the output with docker logs $cid # checkpoint the cont...

The effective type of a data object is the last type information that was associated with it, if any. // a normal variable, effective type uint32_t, and this type never changes uint32_t a = 0.0; // effective type of *pa is uint32_t, too, simply // because *pa is the object a uint32_t* pa = &a...

-- Create demo database CREATE DATABASE SQL2016_Demo ON PRIMARY ( NAME = N'SQL2016_Demo', FILENAME = N'C:\Dump\SQL2016_Demo.mdf', SIZE = 5120KB, FILEGROWTH = 1024KB ) LOG ON ( NAME = N'SQL2016_Demo_log', FILENAME = N'C:\Dump\SQL2016_Demo_log.ldf', ...

SELECT OBJECT_ID('MemOptTable1') AS MemOptTable1_ObjectID, OBJECT_ID('MemOptTable2') AS MemOptTable2_ObjectID GO SELECT name,description FROM sys.dm_os_loaded_modules WHERE name LIKE '%XTP%' GO Show all Memory Optimized Tables: SELECT name,type_desc,durability_desc,...

For example, this is traditional tempdb-based table type: CREATE TYPE dbo.testTableType AS TABLE ( col1 INT NOT NULL, col2 CHAR(10) ); To memory-optimize this table type simply add the option memory_optimized=on, and add an index if there is none on the original type: CREATE TYPE dbo....

For faster performance you can memory-optimize your table variable. Here is the T-SQL for a traditional table variable: DECLARE @tvp TABLE ( col1 INT NOT NULL , Col2 CHAR(10) ); To define memory-optimized variables, you must first create a memory-optimized table type and...

Recommendation Because the symbols i and j can represent significantly different things in MATLAB, their use as loop indices has split the MATLAB user community since ages. While some historic performance reasons could help the balance lean to one side, this is no longer the case and now the choice...

CREATE TABLE dbo.Employee ( [EmployeeID] int NOT NULL PRIMARY KEY CLUSTERED , [Name] nvarchar(100) NOT NULL , [Position] varchar(100) NOT NULL , [Department] varchar(100) NOT NULL , [Address] nvarchar(1024) NOT NULL , [AnnualSalary] decimal (10,2) NOT NULL ...

SELECT * FROM Employee FOR SYSTEM_TIME BETWEEN '2014-01-01 00:00:00.0000000' AND '2015-01-01 00:00:00.0000000' WHERE EmployeeID = 1000 ORDER BY ValidFrom;

Returns a table with a rows containing the values that were actual (current) at the specified point in time in the past. SELECT * FROM Employee FOR SYSTEM_TIME AS OF '2016-08-06 08:32:37.91'

Required compiler features can be specified on a target using the command target_compile_features: add_library(foo foo.cpp ) target_compile_features(foo PRIVATE # scope of the feature cxx_constexpr # list of features ) The features must be part of CMAKE_C_COMPILE_FE...

MailApp is the api from Google App Script that can be used to send mail function sendEmails() { var subject = "A subject for your new app!"; var message = "And this is the very first message" var recipientEmail = "[email protected]"; MailApp.sendEmail(rec...

A simple PL/pgSQL function: CREATE FUNCTION active_subscribers() RETURNS bigint AS $$ DECLARE -- variable for the following BEGIN ... END block subscribers integer; BEGIN -- SELECT must always be used with INTO SELECT COUNT(user_id) INTO subscribers FROM users WHERE subscribed...

Sometimes you need to match a literal (sub-)string with a regular expression despite that substring containing RE metacharacters. While yes, it's possible to write code to insert appropriate backslashes to make that work (using string map) it is easiest to just prefix the pattern with ***=, which ma...

Design (layout XML): <AutoCompleteTextView android:id="@+id/autoCompleteTextView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true&...