Structured Query Language (SQL) is the language with which databases are accessed.

The idea behind SQL was that knowledge workers should be able to retrieve information from a relational database using simple commands. The language “SQL” can be divided into 4 categories, with the abbreviation CRUD: “Create”, “Read”, “Update”, “Delete”. Data is stored in tables, with each type of data stored in columns (fields) and the data itself in rows (records).

When reading data, the query (problem) is often constructed using the following terms: “SELECT”, “FROM” and “WHERE”. But these are just examples, there are many other terms that are used. In essence, SQL is the bridge between the applications and the database.