583 search results for "sql"

Manipulating Data Frames Using sqldf – A Brief Overview

August 8, 2012
By

By Josh MillsIntroductionFor those who are learning R and who may be well-versed in SQL, the sqldf package provides a mechanism to manipulate R data frames using SQL. Even for experienced R programmers, sqldf can be a useful tool for data manipulation. This site provides a useful introduction to SQL. The...

Read more »

read.odbc.ffdf & read.dbi.ffdf for fetching large corporate SQL data

If you are into large data but not enormeoulsy big data everyone is talking about and you are tired of finding a solution to get your data with several 10's of millions of records in R without having RAM issues, having a look at the packages ff, ffbase and ETLUtils might be the solution to your...

Read more »

PostgreSQL, Excel, R, and a Really Big Data Set!

April 19, 2012
By
PostgreSQL, Excel, R, and a Really Big Data Set!

At work I’ve started to work with the biggest data set I’ve ever seen!  First, let me qualify my use of the term “Big Data”.  The number of rows in the resultant data set (after much transformation and manipulation in … Continue reading →

Read more »

Get your large SQL data in ff swiftly

Get your large SQL data in ff swiftly

The ff package is great when you are working with large data in R. Data in corporate environments are usually not that large that a Hadoop system is needed to handle it but the data are mostly large enough to make R choke on it's RAM.  T...

Read more »

How to work with Google n-gram data sets in R using MySQL

April 12, 2012
By
How to work with Google n-gram data sets in R using MySQL

In this R tutorial you will learn how to work with Google n-gram data sets with the help of MySQL. The complete R code is included in this post.

Read more »

PostgreSQL Scalability Analysis Deconstructed

April 11, 2012
By
PostgreSQL Scalability Analysis Deconstructed

In 2010, I presented my universal scalability law (USL) at the SURGE conference. I came away with the impression that nobody really understood what I was talking about (quantifying scalability) or, maybe DevOps types thought it was all too hard (math). Since then, however, I've come to find out that people like Baron Schwartz did get it...

Read more »

A graphical overview of your MySQL database

March 18, 2012
By
A graphical overview of your MySQL database

If you use MySQL, there’s a default schema called ‘information_schema‘ which contains lots of information about your schemas and tables among other things. Recently I wanted to know whether a table I use for storing the results of a large … Continue reading →

Read more »

Capturing Tick Data via C#, Interactive Brokers, and MySQL

March 3, 2012
By
Capturing Tick Data via C#, Interactive Brokers, and MySQL

Interactive Brokers is a discount brokerage that provides a good API for programatically accessing their platform.  The purpose of this post is to create an application that will capture tick level data and save that data into a database for futur...

Read more »

Query a MySQL Database from R using RMySQL

December 15, 2011
By

I use this all the time, and the setup is dead simple. Follow the code below to load the RMySQL package, connect to a database (here the UCSC genome browser's public MySQL instance), set up a function to make querying easier, and query the database to ...

Read more »

RMySQL: using the latest MySQL version

December 15, 2011
By
RMySQL: using the latest MySQL version

In order to connect my R related stuff to a webserver and MySQL I went all the way from using xampp to setting up my own (W)AMPP  (Apache MySQL PHP Perl) to finally back to xampp. And I’m quite happy about this very last switch to xampp! Why I like xampp it can be run … Continue reading...

Read more »