tianchaijz

PostgreSQL JSON Cheatsheet

Using JSON in Postgres by example.

Quick setup via Docker

1. Download and install: Docker Toolbox
2. Open Docker Quickstart Terminal
3. Start a new postgres container:
   docker run --name my-postgres -e POSTGRES_PASSWORD=mysecretpassword -d postgres

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PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

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Postgres Cheatsheet

This is a collection of the most common commands I run while administering Postgres databases. The variables shown between the open and closed tags, "<" and ">", should be replaced with a name you choose. Postgres has multiple shortcut functions, starting with a forward slash, "". Any SQL command that is not a shortcut, must end with a semicolon, ";". You can use the keyboard UP and DOWN keys to scroll the history of previous commands you've run.

Setup

installation, Ubuntu

http://www.postgresql.org/download/linux/ubuntu/ https://help.ubuntu.com/community/PostgreSQL

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.PHONY: using-gcc using-gcc-static using-clang

using-gcc:
	g++-4.8 -o main-gcc -lasan -O -g -fsanitize=address -fno-omit-frame-pointer main.cpp && \
	ASAN_OPTIONS=symbolize=1 ASAN_SYMBOLIZER_PATH=$(shell which llvm-symbolizer) ./main-gcc

using-gcc-static:
	g++-4.8 -o main-gcc-static -static-libstdc++ -static-libasan -O -g -fsanitize=address -fno-omit-frame-pointer main.cpp && \
	ASAN_OPTIONS=symbolize=1 ASAN_SYMBOLIZER_PATH=$(shell which llvm-symbolizer) ./main-gcc-static

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Latency Comparison Numbers
--------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

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// ============================================================================
// gzstream, C++ iostream classes wrapping the zlib compression library.
// Copyright (C) 2001  Deepak Bandyopadhyay, Lutz Kettner
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,

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function check_auto_buy() {
    if (!$('#content_autosubmitcheckticketinfo').is(':visible')) {
        // auto buy ticket window didn't show up
        return false;
    }
    
    var all_zero = true;
    $('#sy_ticket_num_id strong').each(function(i, val){
        if (0 != $(val).text()) {
            all_zero = false;

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/*
 * 使用方法：
 * 1. 设置好自动查询
 * 2. 打开控制栏
 *    windows下无论什么浏览器按快捷键F12
 *    Mac下按快捷键 Command + option + I
 * */
 
function autoCheck(){
    if($('#sear-result').width() || $('#qd_closeDefaultWarningWindowDialog_id').width()){

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#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <clocale>
#include <cstring>
#include <cstdlib>
#include <csignal>
#include <ctime>
#include <cerrno>

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package main

import (
	"fmt"
	"log"
	"strings"
)

// Ops
const (