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yii migrate/down # revert the most recently applied migration yii migrate/down 3 # revert the most 3 recently applied migrations

By default, migrations are applied to the same database specified by the db application component. If you want them to be applied to a different database, you may specify the db command-line option like shown below: yii migrate --db=db2

yii migrate/redo # redo the last applied migration yii migrate/redo 3 # redo the last 3 applied migrations

yii migrate/history # showing the last 10 applied migrations yii migrate/history 5 # showing the last 5 applied migrations yii migrate/history all # showing all applied migrations yii migrate/new # showing the first 10 new migrations yii migrate/new 5 # showing the first 5 ...

yii migrate/mark 150101_185401 # using timestamp to specify the migration yii migrate/mark "2015-01-01 18:54:01" # using a string that can be parsed by strtotime() yii migrate/mark m150101_185401_create_news_table # using full name yii migrate/mark 13...

yii migrate This command will list all migrations that have not been applied so far. If you confirm that you want to apply these migrations, it will run the up() or safeUp() method in every new migration class, one after another, in the order of their timestamp values. If any of the migrations fa...

Set memory limit and disable swap limit docker run -it -m 300M --memory-swap -1 ubuntu:14.04 /bin/bash Set both memory and swap limit. In this case, container can use 300M memory and 700M swap. docker run -it -m 300M --memory-swap 1G ubuntu:14.04 /bin/bash

WCF tracing is built on top of System.Diagnostics. To use tracing, you should define trace sources in the configuration file or in code. Tracing is not enabled by default. To activate tracing, you must create a trace listener and set a trace level other than "Off" for the selected trace s...

We can use Predefined Constants for Date format in date() instead of the conventional date format strings since PHP 5.1.0. Predefined Date Format Constants Available DATE_ATOM - Atom (2016-07-22T14:50:01+00:00) DATE_COOKIE - HTTP Cookies (Friday, 22-Jul-16 14:50:01 UTC) DATE_RSS - RSS (Fri, 22...

Installation Requirements The minimum requirement by this project template is that your Web server supports PHP 5.4.0. Yii2-advanced-app can be installed in two ways. They are Installing via Composer Installing from an Archive File 1) Installing via Composer If you do not already have Comp...

First, download the compiler and components. Next, add Swift to your path. On macOS, the default location for the downloadable toolchain is /Library/Developer/Toolchains. Run the following command in Terminal: export PATH=/Library/Developer/Toolchains/swift-latest.xctoolchain/usr/bin:"${PATH}...

Technically, autoloading works by executing a callback when a PHP class is required but not found. Such callbacks usually attempt to load these classes. Generally, autoloading can be understood as the attempt to load PHP files (especially PHP class files, where a PHP source file is dedicated for a ...

A std::vector can be useful for returning a dynamic number of variables of the same type. The following example uses int as data type, but a std::vector can hold any type that is trivially copyable: #include <vector> #include <iostream> // the following function returns all integers...

The 0b prefix can be used to represent Binary literals. Binary literals allow constructing numbers from zeroes and ones, which makes seeing which bits are set in the binary representation of a number much easier. This can be useful for working with binary flags. The following are equivalent ways o...

Define AccumulatorParam import org.apache.spark.AccumulatorParam object StringAccumulator extends AccumulatorParam[String] { def zero(s: String): String = s def addInPlace(s1: String, s2: String)= s1 + s2 } Use: val accumulator = sc.accumulator("")(StringAccumulator) sc.pa...

Define AccumulatorParam: from pyspark import AccumulatorParam class StringAccumulator(AccumulatorParam): def zero(self, s): return s def addInPlace(self, s1, s2): return s1 + s2 accumulator = sc.accumulator("", StringAccumulator()) def add(x): gl...

Imagine you have the following HTML: <div> <label>Name:</label> John Smith </div> And you need to locate the text "John Smith" after the label element. In this case, you can locate the label element by text and then use .next_sibling property: from ...

BeautifulSoup has a limited support for CSS selectors, but covers most commonly used ones. Use select() method to find multiple elements and select_one() to find a single element. Basic example: from bs4 import BeautifulSoup data = """ <ul> <li class="item&quo...

When the destructor for std::thread is invoked, a call to either join() or detach() must have been made. If a thread has not been joined or detached, then by default std::terminate will be called. Using RAII, this is generally simple enough to accomplish: class thread_joiner { public: thre...

Leading Zeros let number: Int = 7 let str1 = String(format: "%03d", number) // 007 let str2 = String(format: "%05d", number) // 00007 Numbers after Decimal let number: Float = 3.14159 let str1 = String(format: "%.2f", number) // 3.14 let str2 = String(format: &...