The abbreviation “SQL” stands for “Structured Query Language”. This is a kind of programming language designed to make it easy to extract specific information from the database. By the way, can become your assistant in the world of SQL. Most companies store their information in databases. All of them use at least one of the DBMS (for example, MySQL, PostgreSQL, Microsoft SQL Server).

The main advantages of SQL:

  • accuracy: it is possible not to store redundant data;
  • flexibility: even the most complex queries are easy to execute;
  • scalability: multiple users can work with one database;
  • security: only certain users have access to the data in the tables.

A relational database is a space in which related information is stored in multiple tables. At the same time, it is possible to request information in several tables at the same time.

Let’s say a businessman wants to see information about the sales of his goods. Нe can set up a spreadsheet in Excel with all the information he needs to track, in the form of separate columns (order number, date, invoice number, etc).This works when there is only one order from the buyer. If he continues to enter information into the Excel spreadsheet, he will find that the same information is stored in several rows of the spreadsheet. This is how redundant data appears.

There will be no such problems with relational SQL. This system allows to get all the information about the customer for any particular order, but thanks to SQL, you need to save it only once, and not output it again for each individual order.