Tag: constraints

Feed: Planet MySQL; Author: MySQL Performance Blog; Do you wonder if MySQL tells you the truth about writes to tables that have foreign key constraints? The situation is complex, and getting visibility on what is really happening can be a problem. I found this issue intriguing and decided to share and highlight some examples. Query Plan Let us take this example table: CREATE TABLE `product` (   `category` int NOT NULL,   `id` int NOT NULL,   `price` decimal(10,0) DEFAULT NULL,   PRIMARY KEY (`category`,`id`) ) ENGINE=InnoDB; CREATE TABLE `product` (  `category` int NOT NULL,  `id` int NOT NULL,  `price` decimal(10,0) DEFAULT NULL,  PRIMARY KEY (`category`,`id`)) ENGINE=InnoDB; ... Read More

Feed: Recent Announcements. This launch also provides customers with the ability to include special purpose extensions in certificates. This includes the name constraint extension in CA certificates. Name constraints are rules for allowing or preventing subject names in certificates. For example, an organization can now create a name-constrained CA for their cloud infrastructure, separate from their on-premises CAs, and require all certificates to use the subject name “.cloud.example.com”. ACM Private CA now also supports any custom extension for end-user certificates. This includes the Qualified Certificate extension used with Qualified Web Authentication Certificates (QWAC), which are a specific EU form of website certificate ... Read More

Feed: Planet PostgreSQL. One of the things that makes Postgres so awesome for software development is the incredibly useful system of constraints. Constraints are a way to tell Postgres which kinds of data can be inserted into tables, columns, or rows.  ... Read More

Feed: Planet PostgreSQL. Most of my readers will know about primary keys and all kinds of table constraints. However, only a few of you may have ever thought about the difference between a primary key and a UNIQUE constraint. Isn’t it all just the same? In both cases, PostgreSQL will create an index that avoids duplicate entries. So what is the difference? Let’s dig in and find out…What primary keys and UNIQUE constraints doThe following example shows both a primary key and a unique constraint: test=# CREATE TABLE t_sample (a int PRIMARY KEY, b int UNIQUE); CREATE TABLE test=# d ... Read More

Feed: R-bloggers. Author: Michael Mayer. library(farff) library(OpenML) library(dplyr) library(xgboost) set.seed(83454) rmse <- function(y, pred) { sqrt(mean((y-pred)^2)) } # Load King Country house prices dataset on OpenML # ID 42092, https://www.openml.org/d/42092 df <- getOMLDataSet(data.id = 42092)$data head(df) # Prepare df <- df %>% mutate( log_price = log(price), log_sqft_lot = log(sqft_lot), year = as.numeric(substr(date, 1, 4)), building_age = year - yr_built, zipcode = as.integer(as.character(zipcode)) ) # Define response and features y <- "log_price" x <- c("grade", "year", "building_age", "sqft_living", "log_sqft_lot", "bedrooms", "bathrooms", "floors", "zipcode", "lat", "long", "condition", "waterfront") m <- length(x) # random split ix <- sample(nrow(df), 0.8 * nrow(df)) y_test <- ... Read More

Feed: SAS Blogs. Author: Rick Wicklin. Sometimes we can learn as much from our mistakes as we do from our successes. Recently, I needed to solve an optimization problem for which the solution vector was a binary vector subject to a constraint. I was in a hurry. Without thinking much about what I was doing, I decided to eliminate the constraint by introducing a penalty term into the objective function. I then solved the unconstrained penalized optimization problem. A few days later, I thought further about what I had done. I had reformulated a constrained optimization problem as an ... Read More

Feed: Planet PostgreSQL. In PostgreSQL and many other relational databases, constraints are an integral part of the feature set. Many people are aware of primary keys, foreign keys, CHECK-constraints, table constraints and so on. However, from time to time, the situation is way more complicated. That’s when some more advanced techniques are needed to enforce integrity in the way it is desired by end users.In this post, we will elaborate on restrictions spanning more than one row. What does that mean? Let us envision a simple scenario: We want to store information about airplane ownership. In aviation, it happens more ... Read More

Feed: The Connector by Workato. Author: Anna Kelley; Your organization is in the API game, utilizing API connections to integrate and automate its services and processes. But are you maximizing the potential of those integrations? If you’re on the varsity squad, you might be used to the traditional SOAP (simple object access protocol) API playbook. It’s time to consider how REST APIs—which offer standardized, scalable, and high-performance integrations—can optimize your team’s performance.  There are instances in which a faster, more agile, and more lightweight group of players is who you need on the court to make the right play. These ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: Roberto Quadrini. Epoch0: 1618000449 “Transform limits into constraints to create flexibility” — Roberto Quadrini Goal: Discuss solutions, methodologies, systems, projects to support the Energy Transition towards Energy Convergence Target: Operators, Customers, Regulators, Legislators, Inventors, Academics, Scientists, Enthusiasts Market: #EnergyTransition Power: [mW] TAG: #Epoch #Optimize #PowerMarket #Blockchain #Method #EnergyOptimization #DemandSideResponseAggregator #Electricity #EnergyTransition #DemandSide #ResponseSide #EnergyConvergence #CommoditiesAsAService #EnergyMarket #Supply #Demand #Validator #EU #Response #FlexibilityServices #Ledger #Pool #Consensus #Staking #Mining #EpochONE #MathModel #Algorithm #MachineLearning #DeepLearning #Artificialntelligence #Blockchain #ElectricalFlexibility #Resilience #EnergyCommunity #DemandResponse #GreenDeal #NegaWhEXchange Inspiration: #Aristotle, #GalileoGalilei, #LudwigVonMises #LuigiEinaudi#AbrahamCresques Ledger: Roberto Quadrini [IT] Validator: Stefano ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: OLIVIA CUTHBERT. The increasing constraints of the perimeter have opened up avenues for technological invention. Although there are some serious concerns regarding web applications' security, developments around the world have not stopped. However, this has resulted in the increased use of technology, providing companies with new ways of doing business and recent software trends.   In almost every industry sector, the market dynamics are changing, which has changed the phase of technology as we know it today. But it's not just technology and technology trends evolving; many things have changed this ... Read More