Of all the programming languages you need to learn in the IT industry, SQL is one of the most important. SQL is such an integral part of modern big data access and organizational processes that it’s never a bad idea to understand the basics of this language, even if you don’t work in the IT industry.
This article explains what SQL is, how it works, and when this language is used for day-to-day operations.
What is SQL?
SQL stands for ‘structured query language’. This core programming language is mainly used to manipulate or interact with information databases.
For example, when a computer requests information from a local library, SQL facilitates information transfer between that terminal and the library’s database.
However, SQL is also widely used by companies. SQL enables enterprises to access and organize the mountains of data they collect from their customers, which is becoming more common and important today.
Related: Learn how to manage data like a pro with this SQL course
SQL was created in the 1970s by IBM labs. Scientists at IBM created SQL to take advantage of a new database software system called System R. SQL was needed to manage all the data stored in System R.
SQL was initially called Sequel, where the language got its acronym and spoken name. SQL was then updated in 1979 by Relational Software, a company that later became Oracle. Oracle changed SQL to Oracle V2, a modified version of SQL.
Today, SQL is still widely used around the world for various purposes.
To be more specific, SQL allows users to:
- Perform precise queries on a database or data collection as a “relational database”.
- Retrieve or update records and data in a database.
- Add new records to a database.
- Delete old records in the database.
- Create new databases or create new tables in the same database for further optimization and organization.
- Create stored procedures and views for a database.
- Set user permissions for procedures, views, tables, and database datasets.
In other words, SQL allows users to accurately access and manipulate their datasets in an efficient, streamlined manner.
SQL servers and relational database management systems or RDMS are available from organizations such as Microsoft in their Microsoft SQL Server (MS SQL). It is a standard of the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO).
What is SQL used for?
At its core, SQL is used to access and manipulate database information.
For example, companies can use SQL to change, add, delete, or otherwise organize data stored in private databases.
In addition, companies can use SQL programs to create and modify data tables, an essential part of data analysis and understanding.
Note that a “database” is any tool used to collect and organize dense information under these circumstances. For example, databases can store customer information, transaction information, and much more.
SQL is often required for other programs or programming languages to communicate with databases stored on remote or on-site servers.
Python, Javascript or any other standard language can communicate with an SQL database, which uses its own data manipulation language (DML)/data definition language (DDL). A SQL protocol accesses the data before fetching it and translating it into an output or format that Python can understand/display to an end user.
In general, SQL is essential for the following:
- View or delete data.
- Editing data in databases.
- Assist with data analysis.
- Connecting different programs or programming languages to databases.
Given its versatility and importance, SQL is one of the best programming languages to learn. If you want to work in the IT industry at some point, becoming fluent in SQL standards will bolster your resume and career prospects.
Related: Transform data into breakthrough insights with this SQL course
Main elements of SQL
The SQL language has several essential elements that dictate language syntax and format. All language commands in database management systems or databases are executed through specialized SQL command line interfaces or CLIs.
The key elements of SQL include:
- Clauses – these are components of SQL statements or queries.
- Expressions — which create scalar values or tables, usually consisting of rows and columns of data.
- Predicates — which specify conditions and are used to limit statement effects or queries.
- Queries – these are actions to retrieve data based on specific criteria.
- Statements — used to manage transactions, run diagnostics, make connections, and modify program flow or sessions.
Very generally, when a database system uses SQL, SQL statements issue queries from a client program or server that stores data. The server then processes SQL statements and provides responses to the client program or terminal.
In this way, SQL allows users to perform many data manipulation operations quickly and efficiently using direct data entry.
Ordinary SQL commands
To better understand SQL and how it works, it helps to understand some of the most common SQL commands.
Here are just a few examples:
- Create Database — a command used to create a database.
- Create Table — used to create tables.
- Select – which is used to search or extract data from a database.
- Update — allows users to edit or modify data.
- Delete — allows users to delete certain data.
- Drop — used to drop databases or tables.
- Insert Into – allows users to insert new data into a database.
SQL is such a comprehensive and versatile language that it also contains much more complex commands. As a data control language, data analysts spend a lot of time learning the ins and outs of the database tables, database objects, relational models, and data types.
How does SQL work?
Although there are different versions or frameworks for SQL, MySQL is the most commonly used framework. MySQL is an open-source version of this programming language that facilitates the primary role of SQL, enabling organizations to quickly manage their backend data and web applications.
For example, companies like Instagram, Facebook and more use SQL for data processing and backend data storage.
So, how does all this work? When a user or programmer writes an SQL query, it is written and executed (or “parsed” in official terminology) and a query optimizer then processes it. Once the SQL query reaches the SQL server, it goes through three distinct stages: parsing, binding, and optimization.
Very simply put:
- Parsing is an SQL process that checks the syntax for the query.
- Binding is an SQL process that checks the semantics or details of the query.
- Optimization is an SQL process that generates the query execution plan or executes the requested command.
If you want to learn more about this, you can take some SQL courses for your personal knowledge or your company.
Related: How to take control of your data with Microsoft SQL for just $40
Many of these courses are quite affordable, so it doesn’t take much to learn SQL, even for beginners, to data science or SQL syntax.
The SQL compilation process explained
Here’s a breakdown of the SQL compilation process in a little more detail.
Parsing takes place first. This tokenizes the SQL statement into several words and checks them for verbiage, clauses, and specific symbols. Then the SQL server checks the semantics. This means that it validates the statement to ensure that it is legit or understandable.
In other words, the server makes sure that the SQL query makes sense. Many servers also ensure that the data the user is requesting exists and that the user has the appropriate permissions to perform a specific query.
Then it comes binding. In this phase, the SQL server creates a query plan for the received statement. This forms a binary representation of all the steps required to execute the query or statement in bytecode.
This renders the compilation as a command-line shell, a program that can read SQL statements and send them to a database server for optimization and execution.
At this stage, the SQL server optimizes the query plan and chooses the ideal algorithms for searching or storing data. Depending on the server or program, it may use a feature called query optimization or a “relational engine.”
Finally, the server executes the SQL statement by executing the query plan, depending on what exactly needs to be done.
Related: Learn how to manage data like a pro with this SQL course
Overview
SQL is one of the most crucial programming languages and companies use it on a daily basis.
Now you know how SQL works, why it’s essential and how to use it to your advantage – a critical skill whether you need to build a business website or enter the IT sector.
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