Tag: column

Feed: Planet PostgreSQL. proposed by PostgreSQL contributor Alvaro Herrera. BRIN stands for “Block Range INdex”. A block range is a group of pages adjacent to each other, where summary information about all those pages is stored in Index.  For example, Datatypes like integers – dates where sort order is linear – can be stored as min and max value in the range. Other database systems including Oracle announced similar features later. BRIN index often gives similar gains as Partitioning a table.BRIN usage will return all the tuples in all the pages in the particular range. So the index is lossy ... Read More

Feed: Planet MySQL; Author: Meenakshi Agarwal; This tutorial explains the MySQL INSERT command to insert single and multiple rows in a table. Here, you’ll find some unique ways with different variations for adding records with fully working examples.1. INSERT Statement Syntax2. INSERT Single Row3. INSERT Default Values3. INSERT Date Columns4. INSERT Multiple RowsLet’s now read and understand each of the section one by one.MySQL INSERT statementAs stated initially, the INSERT command is a built-in MySQL statement which inserts the specified records into a given table. So, let’s first check the details and see how to use the INSERT command. But ... Read More

Feed: Planet PostgreSQL. Declarative partitioning got some attention in the PostgreSQL 12 release, with some very handy features. There has been some pretty dramatic improvement in partition selection (especially when selecting from a few partitions out of a large set), referential integrity improvements, and introspection.In this article, we’re going to tackle the referential integrity improvement first. This will provide some sample data to use later for the other explanations. And the feature is just amazingly cool, so it goes first anyway. This example builds on the example given for the Generated columns in PostgreSQL 12 article, where we built a ... Read More

Feed: Planet MySQL; Author: The Pythian Group; In one of my latest database restore jobs, I was helping a MySQL client with issues related to mysqlbinlog and I wanted to share it here. In case you didn’t know, MySQL is a simple SQL shell with input line editing capabilities, while mysqlbinlog is a utility for processing binary logs a MySQL server. In this case, the server was MariaDB, but the utilities are the same. The database version was 10.1.38-MariaDB. So, why use mysqlbinlog? There are many reasons for using mysqlbinlog to process binary log files, but in this case, it ... Read More

Feed: Planet MySQL; Author: Thorben Janssen; Hibernate Tips is a series of posts in which I describe a quick and easy solution for common Hibernate questions. If you have a question for a future Hibernate Tip, please post a comment below. Question: One of the readers of my article about using Hibernate with a MySQL database asked the following question: What is the difference between the following two recommended approaches concerning the primary keys? @GeneratedValue(strategy = GenerationType.IDENTITY) @GeneratedValue(generator = "native") @GenericGenerator(name = "native", strategy = "native") Solution: As so often in software development, the answer to that question is: “It depends ... Read More

Feed: R-bloggers. Author: Mark White. Simulating data is an invaluable tool. I use simulations to conduct power analyses, probe how robust methods are to violating assumptions, and examine how different methods handle different types of data. If I’m learning something new or writing a model from scratch, I’ll simulate data so that I know the correct answer—and make sure my model gives me that answer. But simulations can be complicated. Many other programming languages require for loops to do a process multiple times; nesting many conditional statements and other for loops within for loops can quickly be difficult to read ... Read More

Feed: R-bloggers. Author: kjytay. I recently learned how to use the choroplethr package through a short tutorial by the package author Ari Lamstein (youtube link here). To cement what I learned, I thought I would use this package to visualize flood insurance claims. I am using the FIMA NFIP redacted claims dataset from FEMA, and it contains more than 2 million claims transactions going all the way back to 1970. (The dataset can be accessed from this URL.) From what I can tell, this dataset is updated somewhat regularly. For this post, the version of the dataset used was published ... Read More

Feed: Planet MySQL; Author: Krunal Lathiya; SQL Views Example | Views In SQL Tutorial is today’s topic. SQL views is a kind of virtual tables which have rows and columns as they are in a real database. A view can be accompanied with all the rows of a particular table or selected rows based on a certain condition. In Structured Query Language, a view is a virtual table based on the result-set of an SQL statement. Content Overview SQL VIEWS SQL view contains rows and columns, just like the real table. The fields in the view are fields from one ... Read More

Feed: R-bloggers. Author: John Mount. While reading Dr. Nina Zumel’s excellent note on bias in common ensemble methods, I ran the examples to see the effects she described (and I think it is very important that she is establishing the issue, prior to discussing mitigation). In doing that I ran into one more avoidable but strange issue in using xgboost: when run for a small number of rounds it at first appears that xgboost doesn’t get the unconditional average or grand average right (let alone the conditional averages Nina was working with)! Let’s take a look at that by running a ... Read More

Feed: Planet MySQL; Author: Meenakshi Agarwal; This tutorial explains MySQL ABS() which is a Math/Trig function. It takes a number as input and determines its absolute (positive) value. We’ll describe the usages of this method with the help of simple examples.1. ABS() Syntax2. ABS() Simple Examples3. ABS() for Expression4. ABS() with TablesLet’s now go through each of the section one by one.MySQL ABS() FunctionAs stated initially, ABS() is a built-in MySQL function which does some math calculation to derive the absolute value of a number.In Maths term, an absolute value represents the length of a number on the number line ... Read More