What Is SQL and How Does It Work?
SQL is behind your computer's ability to access database information. Discover SQL, how it works and more in this guide.
Out of all the programming languages you need to learn in the IT industry, SQL is one of the most important. SQL is so integral to modern big data access and organization processes that it's never a bad idea to grasp the basics of this language, even if you don't work in the IT industry.
This article will break down what SQL is, how it works and when this language is used for everyday operations.
What is SQL?
SQL stands for "structured query language." This core programming language is primarily used to manipulate or communicate 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 frequently used by businesses. SQL enables enterprises to access and organize the mountains of data they collect from their customers, which is increasingly common and important today.
SQL was created in the 1970s by IBM laboratories. 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, which is 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 into Oracle V2, a modified version of SQL.
Today, SQL is still widely used around the world for a variety of purposes.
To be more specific, SQL allows users to:
- Execute precise queries against a database or collection of data as a "relational database."
- Retrieve or update records and data in a database.
- Insert new records into a database.
- Delete old records in the database.
- Make new databases or create new tables in the same database for further optimization and organization.
- Make stored procedures and views for a database.
- Set user permissions for procedures, views, tables and database data sets.
In other words, SQL allows users to accurately access and manipulate their data sets in an efficient, streamlined way.
SQL servers and relational database management systems or RDMS, are available from organizations like Microsoft in their Microsoft SQL Server (MS SQL). It's 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, businesses may use SQL to modify, add to, remove or otherwise organize data stored in private databases.
In addition, businesses can use SQL programs to create and alter data tables: an essential part of data analysis and understanding.
Note that a "database" is any tool used to collect and organize dense information in these circumstances. Databases, for example, can store customer information, transaction information and much more.
SQL is often needed for other programs or programming languages to interface with databases stored on remote or on-site servers.
Overall, SQL is essential for the following:
- Accessing or removing data.
- Editing data in databases.
- Assisting with data analytics.
- Connecting different programs or programming languages with databases.
Given its versatility and importance, SQL is one of the best programming languages to learn. If you want to join the IT industry at any point, becoming fluent in SQL standards will bolster your resume and career prospects.
Major elements of SQL
The SQL language has several vital elements that dictate its language syntax and format. All language commands in database management systems or databases are executed through specialized SQL command line interfaces or CLIs.
The significant elements of SQL include:
- Clauses — which are components of SQL statements or queries.
- Expressions — which make scalar values or tables and which usually consist of rows and columns of data.
- Predicates — which specify conditions and are used to limit statement effects or queries.
- Queries — which are actions to retrieve data based on specific criteria.
- Statements — which are used to control transactions, perform diagnostics, make connections, and adjust program flow or sessions.
Very broadly, when a database system uses SQL, SQL statements send queries from a client program or server where data is stored. The server then processes SQL statements and gives replies to the client program or terminal.
In this way, SQL lets users execute many data manipulation operations quickly and efficiently using direct data inputs.
Common 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 — which is used to create tables.
- Select — which is used either find or extract data from a database.
- Update — which allows users to edit or make adjustments to data.
- Delete — which enables users to delete some data.
- Drop — which is used to remove databases or tables.
- Insert into — which lets users insert fresh data into a database.
SQL is such a comprehensive and versatile language that it also includes many more complex commands. As a data control language, data analysts spend a lot of time learning the ins and outs of its database tables, database objects, relational models and data types.
How does SQL work?
While there are different versions or frameworks for SQL, the most common framework used is MySQL. MySQL is an open-source version of this programming language that facilitates the primary role of SQL, enabling organizations to manage their backend data and web applications quickly.
For instance, companies like Instagram, Facebook and more use SQL for data processing and backend data storage.
So, how does this all work? When a user or programmer writes an SQL query, it is written and run (or "parsed" according to the official terminology) and a query optimizer then processes it. Once the SQL query reaches the SQL server, it goes through three distinct phases: parsing, binding and optimization.
Put very simply:
- Parsing is an SQL process that checks syntax for the query.
- Binding is an SQL process that checks the query's semantics or details.
- Optimization is an SQL process that generates the query execution plan or that carries out the requested command.
If you want to know more about this, you can take some SQL courses for your personal knowledge or your company.
Many of these courses are reasonably affordable, so it doesn't take much to learn SQL, even for beginners, to data science or SQL syntax.
The SQL compiling process explained
Here's a breakdown of the SQL compiling process in a little more detail.
First, parsing takes place. This tokenizes the SQL statement into different words, checking them for verbiage, clauses and specific symbols. Next, the SQL server will check semantics. This means it validates the statement to ensure it is legitimate or understandable.
In other words, the server ensures that the SQL query makes sense. Many servers also provide that the data the user requests exists and the user has the appropriate privileges to execute a specific query.
Then comes binding. The SQL server makes a query plan for the received statement during this stage. This forms a binary representation of any steps needed to carry out the query or statement in byte code.
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."
Last, the server executes the SQL statement by running the query plan depending on what exactly needs to be done.
SQL is one of the most crucial programming languages, and businesses use it daily.
Now you know how SQL works, why it's essential and how to leverage it for your advantage: a critical skill whether you need to build a business website or want to get into the IT sector.
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