A query is a question or a request for information expressed in a formal manner. In computer science, a query is essentially the same thing, the only difference is the answer or retrieved information comes from a database.
What is a database query?
A database query is either an action query or a select query. A select query is one that retrieves data from a database. An action query asks for additional operations on data, such as insertion, updating, deleting or other forms of data manipulation.
This doesn't mean that users just type in random requests. For a database to understand demands, it must receive a query based on the predefined code. That code is a query language.
What is a query in SQL?
Query languages are used to make queries in a database, and Microsoft Structured Query Language [SQL] is the standard. Note: SQL and MySQL are not the same, as the latter is a software extension that uses SQL. Other language extensions of the language include Oracle SQL and NuoDB.
Although Microsoft's SQL is the most popular language, there are many other types of databases and languages. These include NoSQL databases and graph databases, Cassandra Query Language [CQL], Data Mining Extensions [DMX], Neo4j Cypher and XQuery.
How do queries work?
Queries can accomplish a few different tasks. Primarily, queries are used to find specific data by filtering explicit criteria. Queries also help automate data management tasks, summarize data and engage in calculations.
Other examples of queries include append, crosstab, delete, make a table, parameter, totals and updates.
Meanwhile, a query parameter runs variations of a particular query, prompting users to insert a field value and then use that value to create a criterion. Totals queries, on the other hand, allow users to group and summarize data.
An example of SQL query.In a relational database, which contains records or rows of information, the SQL SELECT statement query allows users to choose data and return it from a database to an application. The resulting query is stored in a result table, which is called a result-set. Users can break down the SELECT statement into other categories like FROM, WHERE and ORDER BY. The SQL SELECT query can also group and aggregate data to analyze or summarize.
At its most basic, a query is like ordering a cup of coffee at a cafe. You walk up to the barista and make your request by asking, "May I have a cup of coffee?" The barista understands your request and gives you a cup of coffee. Queries work in the same way.
A query gives meaning to the lines of code used in every query language. As such, both the user and the database exchange information as they both "speak" the same language. Querying by language is not the only way to request information from a database, though. Other popular examples include users performing a query by example or by using available parameters.
What is query folding?
For data sources like relational and non-relational databases like Active Directory, OData or Exchange, a mashup engine "translates" from M Language -- the data transformation language of Power Query [a data mashup and transformation tool] -- to a language understood by the underlying data source. Most often, that language would be SQL.
When complex calculations and transformations are pushed directly to the source, Power Query uses robust relational database engines developed to handle large volumes of data efficiently.
Query folding describes Power Query's ability to generate a single query statement to retrieve and transform source data. The Power Query mashup engine attempts to accomplish query folding to enhance efficiency whenever possible.
Users can also perform hundreds of different data transformations using Power BI, Microsoft's business intelligence platform, which builds in Power Query to engage in query folding. Power BI includes tools that aggregate, analyze, visualize and share data.
Web search query
A web search query describes what users search for when they type a question or a word in search engines such as Bing, Google or Yahoo. Search engine queries provide information that is much different from SQL queries, as they don't require positional parameters or keywords. A search engine query is essentially a request for information on a specific topic.
Search engines uses an algorithm to search and find the most accurate results to requests. They sort these based on significance and according to the particular search engine -- details of which are not revealed publicly.
Types of search queries include navigational, informational and transactional. Navigational searches are intended to find a particular website, such as ESPN.com; informational searches are designed to cover a broad topic, such a comparison between a new iPhone and Android device; and transactional searches seek to complete a transaction, such as the purchase of a new sweater on Amazon.com.
Other kinds of queries
Some queries have nothing to do with the above; among these are querySelector[] in JavaScript and query errors in Facebook.
JavaScript's querySelector[] helps users find the first element that matches a particular CSS selector. To return all matching elements, developers also use the querySelectorAll[] method. Whenever the selector isn't valid, the process raises a SyntaxError exception. If there are no matches, the querySelector[] returns null.
Query errors occur on Facebook for a number of reasons. Whenever this happens, users get a message like "Error performing query." This is usually fixed by rebooting the device, refreshing the page, logging out and logging back in or by clearing the cache and cookies.
Programmers are in high demand these days--their fluency in coding language is invaluable. Knowing various programming languages is a no-brainer for engineers, but a basic understanding of the languages can benefit anyone, even if you're not looking to become a master coder. Grasping some general understanding of coding can help you make the right hires for your business needs, communicate better with the engineers on your team, and prevent any awkward misunderstandings [Ruby isn't a gem, and Java isn't an excellent cup of coffee]. Plus, with the high salaries earned for coding, you might want to consider it for a future career move! So what do you need to know?
Here are the 10 most popular programming languages:
Java is top pick as one of the most popular programming languages, used for building server-side applications to video games and mobile apps. It's also the core foundation for developing Android apps, making it a favorite of many programmers. With its WORA mantra [write once, run anywhere], it's designed to be portable and run happily across multiple software platforms. I first got started with Java server programming back in 1999--it was so exciting, I actually wrote a few books about it. Java is everybody's pal!
Python is a one-stop shop. There's a Python framework for pretty much anything, from web apps to data analysis. In fact, WordStream is written in Python! You're the best bud. Python is often heralded as the easiest programming language to learn, with its simple and straightforward syntax. Python has risen in popularity due to Google's investment in it over the past decade [in fact, one recent study has shown Python to be the most commonly taught programming language in U.S. schools]. Other applications built with Python include Pinterest and Instagram.
If you saw C on a report card, you'd be pretty bummed. Maybe a bit confused, too [is it actually a B-?]. However, C is not the bizarrely bad grade it seems to be. It's often the first programming language taught in college [well, it was for me 10 years ago]. I thought it was a nice "in-between" language in that it was object oriented without having to be fanatical about it. It was also low level enough to be close to hardware, but no so low level that you had to do everything manually. Because there are so many C compilers, you can write stuff in C and have it run pretty much anywhere.
Ruby [also known as Ruby on Rails] is a major supplier of web apps. Ruby is popular due to its ease of learning [it's very straightforward] and power. Ruby knowledge is in high demand these days!
JavaScript [which, confusingly, is not at all related to Java] is another favorite programming language because it's so ubiquitous on the web--it's basically everywhere. JavaScript allows developers to add interactive elements to their website, and its presence is felt across the internet. At WordStream, we use a JavaScript library called JQuery to make our JavaScript work even easier.
C# [pronounced C-sharp, not C-hashtag for you Twitter fans] is the language used in order to develop Microsoft apps. C# is syntactically nearly identical to Java. I've spent much time training with C#, but if you're good at Java, you'll likely have an easy time jumping onto C#. If you're looking to work on Microsoft apps, C# is the way to go. C# opens a lot of Windows [har-har].
PHP [which stands for Hypertext Preprocessor, if you care to know] is often used in conjunction with dynamic data-heavy websites and app development. It provides a ton of power and is the beating heart of monster sites like WordPress and Facebook. What's really cool about PHP is that it's an open-source language, so there are tons of free pre-built modules that you can grab and modify to get your ideal results. PHP is also on the easy end of the learning spectrum, simply requiring you to embed the code within HTML. PHP is a must-learn language for aspiring web developers.
Objective-C is the programming language behind iOS apps. Apple's new language Swift is rising in the ranks, but Objective-C is still the recommended starting point for those looking to craft Apple apps for iPhones and iPads. Next stop--the iOS App Store!
SQL is a database query language [SQL stands for Structured Query Language] that's ideal when talking big data. SQL lets you siphon helpful data from massive databases. Nearly every app has a backend database, and SQL is the language that helps you interact with that sweet data. In terms of software development, SQL isn't ever used alone--rather, you invoke SQL from some other programming knowledge and you have yourself a nice package deal.
C is the predecessor to more complex programming languages like Java and C#. C is best when you want to work small and when dealing with low-level applications. It's widely used for embedded systems like the firmware of your television or the operating system of an airplane, as well as computer operating systems like Windows. For me personally, C was more of an academic language. It was nice to learn how to write a kernel back in college, and you gain a more solid understanding of how newer languages work under the covers, but it's rare for most application developers to ever have to use this today.
There you have it--the king languages of coding. What's your programming language of choice and why? If you're a newbie looking to dive into coding, take a look at these nine spots on the web where you can learn to code [for free]! You'll be a code master in no time.
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