Tag: column

Feed: R-bloggers. Author: Unknown. [This article was first published on Deeply Trivial, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. The arrange function allows you to sort a dataset by one or more variable, either ascending or descending. This function is especially helpful if you plan on aggregating your data with summarize (which, we’ll get to later), so you can select specific rows in that command. It’s similar to the Excel complex sort, ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . There are several ways to move data between SQL Server and MariaDB. Here we will discuss them and we will highlight some caveats. Moving Data Definition from SQL Server to MariaDB To copy an SQL Server data structures to MariaDB, one has to: Generate a CSV file from SQL Server data. Modify the syntax so that it works in MariaDB. Run the file in MariaDB. Variables That Affect DDL Statements DDL statements are affected by some server system variables. sql_mode determines the behavior of some SQL statements and expressions, including how strict ... Read More

Feed: R-bloggers. Author: Sebastian Heinz. [This article was first published on r-bloggers | STATWORX, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. Recently, some colleagues and I attended the 2-day COVID-19 hackathon #wirvsvirus, organized by the German government. Thereby, we’ve developed a great application for simulating COVID-19 curves based on estimations of governmental measure effectiveness (FlatCurver). As there are many COVID-related dashboards and visualizations out there, I thought that gathering the underlying data ... Read More

Feed: Redis Labs. Author: Guy Royse. Like many software engineers, I enjoy a good game of Dungeons & Dragons. I love powering up my character and facing increasingly more powerful foes. Doing this right requires gold and experience. And the best way to get those things is a good old-fashioned dungeon crawl. If you need some context on D&D, this video might help. The short but overly simplified version: in D&D you explore underground complexes, fight monsters therein, and take their gold. Unfortunately, dungeons aren’t set up for the convenience of adventurers like us. Sometimes the monster is challenging but ... Read More

Feed: R-bloggers. Author: Gregory Kanevsky. [This article was first published on novyden, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. Introduction Coronovirus pandemic is changing our lifestyle from daily routine to near- and midterm plans, affecting relationships at home and work, adjusting our economical priorities and abilities, making us reassess value of goods and services, and arguably impacting all aspects of life. Better knowledge and understanding of the decease, its manifestations and dynamics ... Read More

Feed: Planet PostgreSQL. PostgreSQL has a rich set of indexing functionality, and there are many articles explaining the syntax, usage, and value of the index. In this article, I will write basic and useful queries to see the state of database indexes. People develop databases and after some time, when there is a demand to do changes in the architecture of software, they forget to do the previous indexes’ cleanup. This approach creates a mess and sometimes slows down the database because of too many indexes. Whenever we do an update or insert, the index will be updated along with ... Read More

Feed: R-bloggers. Author: Unknown. [This article was first published on Deeply Trivial, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. Announcing my theme for this year’s blogging A to Z! The tidyverse is a set of R packages for data science. The big thing about the tidyverse is making sure your data are tidy. What does that mean? Each row is an observation Each column is a variable Each cell contains only one ... Read More

Feed: Planet PostgreSQL. On 18th of March 2020, Alvaro Herrera committed patch: Enable BEFORE row-level triggers for partitioned tables   ... with the limitation that the tuple must remain in the same partition.   Reviewed-by: Ashutosh Bapat Discussion: https://postgr.es/m/20200227165158.GA2071@alvherre.pgsql So, I never made triggers on partitioned tables, so I was kinda sure that they would work anyway. So I tried: =$ CREATE TABLE users ( username text NOT NULL PRIMARY KEY, fullname text ) partition BY hash (username);   =$ CREATE TABLE users_0 partition OF users FOR VALUES WITH (modulus 2, remainder 0);   =$ CREATE TABLE users_1 partition OF ... Read More

Feed: R-bloggers. Author: kjytay. I’ve been working with sparse matrices in R recently (those created using Matrix::Matrix with the option sparse=TRUE) and found it difficult to track down documentation about what the slots in the matrix object are. This post describes the slots in a class dgCMatrix object. (Click here for full documentation of the Matrix package (and it is a lot–like, 215 pages a lot).) Background It turns out that there is some documentation on dgCMatrix objects within the Matrix package. One can access it using the following code: library(Matrix) ?`dgCMatrix-class` According to the documentation, the dgCMatrix class …is ... Read More

Feed: Planet MySQL; Author: MySQL Performance Blog; In my Webinar on Using Percona Monitoring and Management (PMM) for MySQL Troubleshooting, I showed how to use direct queries to ClickHouse for advanced query analysis tasks. In the followup Webinar Q&A, I promised to describe it in more detail and share some queries, so here it goes.PMM uses ClickHouse to store query performance data which gives us great performance and a very high compression ratio. ClickHouse stores data in column-store format so it handles denormalized data very well. As a result, all query performance data is stored in one simple “metrics” table:Column ... Read More