Tag: row

Feed: R-bloggers. Author: Learning Machines. Have you ever thought about why the definition of a function in R is different from many other programming languages? The part that causes the biggest difficulties (especially for beginners of R) is that you state the name of the function at the beginning and use the assignment operator – as if functions were like any other data type, like vectors, matrices or data frames… Congratulations! You just encountered one of the big ideas of functional programming: functions are indeed like any other data type, they are not special – or in programming lingo, functions ... Read More

Feed: Planet MySQL; Author: MC Brown; Clickhouse is a relatively new analytics and datawarehouse engine that provides for very quick insertion and analysing of data. Like most analytics platforms it’s built on a column-oriented storage basis and unlike many alternatives is completely open source. It’s also exceedingly fast, even on relatively modest platforms.Clickhouse does have some differences from some other environments, for example, data inserted cannot easily be updated, and it supports a number of different storage and table engine formats that are used to store and index the information. So how do we get into that from our MySQL transactional ... Read More

Feed: Planet MySQL; Author: Federico Razzoli; Federico Razzoli  | December 14, 2018 |  Posted In: MariaDB, MySQL PREVIOUS POSTAs mentioned in a previous post, I gave a talk at Percona Live Europe 2018 about system-versioned tables. This is a new MariaDB 10.3 feature, which consists of preserving old versions of a table rows. Each version has two timestamps that indicate the start (INSERT,UPDATE) of the validity of that version, and its end (DELETE, UPDATE). As a result, the user is able to query these tables as they appear at a point in the past, or how data evolved in a certain time ... Read More

Feed: What's New. Author: Phil Naranjo. Transparent worksheets open up a lot of exciting possibilities to express your creativity. Here are some other helpful tips to make the most of this feature: Data first. Worksheet transparency enables you to create beautiful, stunning dashboards. However, keep in mind that the subject of your data should always drive the formatting and analytical usefulness and readability should always come first. When choosing background images, ensure that those images aren’t obscuring axes, labels, or marks. For starters, stick with visually simpler background images with long stretches of uniform color like a blue sky, the ... Read More

Feed: R-bloggers. Author: R Views. Today we will continue our work on Fama French factor models, but more as a vehicle to explore some of the awesome stuff happening in the world of tidy models. For new readers who want get familiar with Fama French before diving into this post, see here where we covered importing and wrangling the data, here where we covered rolling models and visualization, my most recent previous post here where we covered managing many models, and if you’re into Shiny, this flexdashboard. Our goal today is to explore k-fold cross-validation via the rsample package, and ... Read More

Feed: MemSQL Blog. Author: Floyd Smith. MemSQL CEO Nikita Shamgunov was featured recently on the Data Engineering Podcast with host Tobias Macey. Tobias drew out Nikita on MemSQL’s origins, our exciting present, and where we’re going in the future. We share a few highlights here, but we also urge you to listen to the full episode. The podcast covered a wide variety of topics. In this blog post, we’ll highlight Nikita’s comments on MemSQL’s origins; setting up and running the MemSQL database; typical use cases; and the future of MemSQL. How MemSQL Started Nikita grew up and was educated in ... Read More

Feed: R-bloggers. Author: John Mount. Pipelines in R are popular, the most popular one being magrittr as used by dplyr. This note will discuss the advanced re-usable piping systems: rquery/rqdatatable operator trees and wrapr function object pipelines. In each case we have a set of objects designed to extract extra power from the wrapr dot-arrow pipe %.>%. Piping Piping is not much more than having a system that lets one treat “x %.>% f(.)” as a near synonym for “f(x)”. For the wrapr dot arrow pipe the semantics are intentionally closer to (x %.>% f(.)) ~ {. . The pipe ... Read More

Feed: Databasejournal.com - Feature Database Articles. Author: . Occasionally a join using primary key columns in a query can be eliminated because of the data involved. If Oracle determines that all of the 'required' data is available in a single table, then the optimizer will rewrite the query to eliminate the 'unnecessary' join. Oracle has been doing this for years with the limitation that the primary keys involved were single-column keys. In versions 12.2 and later, multi-column primary keys can be used, however there are cases where the join elimination isn't complete depending upon table order in the FROM clause ... Read More

Feed: Teradata Blog. One of the most common, and arguably the most valuable, data element in any enterprise and integrated data warehouses, is time. Without time dimensions, your data lacks important context of when as well as sequence of events. In fact, analyzing data using time is quite important, so much so that we just do it naturally – even without thinking about it.  It’s evidenced by the fact that most analytics are bound by time - like hour, day, month, year, etc. Simply put: how often are you not using time in some fashion in your analytics?Though vastly important, ... Read More

Feed: Blog. Author: leopicasso; Today’s blog post concludes our four-part look into SQL performance and optimization. Part one introduced and explained relational optimization; part two reviewed query analysis and introduced single-table access path formulation; part three took a look at multi-table SQL optimization… and today we conclude with a quick overview of several additional aspects of SQL optimization that we have yet to discuss.Using Indexes to Avoid Sorts To satisfy certain types of SQL requests it may be necessary for the DBMS to sort data. But sorting is cost prohibitive and should be avoided if at all possible. The relational ... Read More