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TRUNCATE tableName; This will delete all the data and reset AUTO_INCREMENT index. It's much faster than DELETE FROM tableName on a huge dataset. It can be very useful during development/testing. When you truncate a table SQL server doesn't delete the data, it drops the table and recreates it, th...

With a column of one of the string types, named my_date_field with a value such as [the string] 07/25/2016, the following statement demonstrates the use of the STR_TO_DATE function: SELECT STR_TO_DATE(my_date_field, '%m/%d/%Y') FROM my_table; You could use this function as part of WHERE clause a...

perl -ne'print if /foo/' file.txt Case-insensitive: perl -ne'print if /foo/i' file.txt

Weka is a collection of machine learning algorithms for data mining tasks. The algorithms can either be applied directly to a dataset or called from your own Java code. Weka contains tools for data pre-processing, classification, regression, clustering, association rules, and visualization. It is al...

Margin is one of a few CSS properties that can be set to negative values. This property can be used to overlap elements without absolute positioning. div{ display: inline; } #over{ margin-left: -20px; } <div>Base div</div> <div id="over">Overlapping div&lt...

3.0 The => operator has the same precedence as the assignment operator = and is right-associative. It is used to declare lambda expressions and also it is widely used with LINQ Queries: string[] words = { "cherry", "apple", "blueberry" }; int shortestWordLength...

genRandom creates a stream of random numbers that has a one in four chance of terminating each time it's called. def genRandom: Stream[String] = { val random = scala.util.Random.nextFloat() println(s"Random value is: $random") if (random < 0.25) { Stream.empty[String] ...

curl -XPUT 'www.example.com:9200/myIndexName?pretty' Output: { "acknowledged" : true } Reference Link: Here

Let's say there's a collection called Todos and the autopublish package is added. Here is the basic component. import { createContainer } from 'meteor/react-meteor-data'; import React, { Component, PropTypes } from 'react'; import Todos from '/imports/collections/Todos'; export class List exte...

Before you compile your app and run it on your device, you'll need create some icons and splash screens, and add a mobile-config.js file to your app. App.icons({ // iOS 'iphone': 'resources/icons/icon-60x60.png', 'iphone_2x': 'resources/icons/[email protected]', 'ipad': 'resources/icons...

You'll need to separate out your application layer from your database layer, and that means specifying the MONGO_URL. Which means running your app through the bundle command, uncompressing it, setting environment variables, and then launching the project as a node app. Here's how... #make sure you...

Then go into the mongo shell and initiate the replica set, like so: mongo > rs.initiate() PRIMARY> rs.add("mongo-a") PRIMARY> rs.add("mongo-b") PRIMARY> rs.add("mongo-c") PRIMARY> rs.setReadPref('secondaryPreferred')

There's two great utilities for black-box analysis of databases. First is variety.js, which will give you a high-level overview. The second is schema.js, which will let you dig into the collections for more detail on the individual fields. When inheriting a production Mongo database, these two util...

The --url flag can be tricky to use. There is a 60 second window to authenticate, and then the username/password randomly resets. So be sure to have robomongo open and ready to configure a new connection when you run the command. # get the MONGO_URL string for your app meteor mongo --url $METEOR...

Same thing as before, but you have to copy the info into the mongodump command. You have to run the following commands rediculously fast, and it requires hand/eye coordination. Be warned! This is a rediculously hacky! But fun! Think of it as a video game! :D # get the MONGO_URL string for your app ...

This command will create a /dump directory, and store each collection in a separate BSON blob file. This is the best way to backup or transfer databases between systems. mongodump --db meteor

The analog to the meteordump command is meteorrestore. You can do a partial import by selecting the specific collection to import. Particularly useful after running a drop command. # make sure your app is running meteor # then import your data mongorestore --port 3001 --db meteor /path/to/dump...

Mongo supports database-to-database copying, which is useful if you have large databases on a staging database that you want to copy into a local development instance. // run mongod so we can create a staging database // note that this is a separate instance from the meteor mongo and minimongo ins...

Preallocation. Mongo sets aside disk-space in empty containers, so when the time comes to write something to disk, it doesn't have to shuffle bits out of the way first. It does so by a doubling algorithm, always doubling the amount of disk space preallocated until it reaches 2GB; and then each preal...

Gotta rotate those log files, or they'll eventually eat up all of your disk space. Start with some research... mongodb-log-file-growth rotate-log-files Log files can be viewed with the following command... ls /var/log/mongodb/ But to set up log-file rotation, you'll need to do the following.....