Introduction To SQL Language (Structured Query Language)

Hello readers, in this article we will discuss the topic of introduction to SQL (Structured Query Language) in simple terms that anyone can understand the topic easily. SQL is one of the most important topics in programming and also Database Management systems.

First of all the full form of the SQL is Structured Query Language. since it is a language then it is obvious that it is used for communication between any two or more units. Here, in the context of SQL, the two units are the users and the database. So, in short, SQL is a language that is used to communicate with the database. Also, it may be a question that why structured? The simple answer to the question is that it is because the data model is fixed or simply structured. And here the model is in the form of a table or we can say relations in technical terms. Hence, sometimes we even call this topic a relational database management system. So, anytime when we have to query the database to fetch the data or retrieve the data or modify the data or simply perform CRUD operations. So, we call this language as Structured Query Language i.e. the languages used to query the structured database.

First of all, SQL is a domain-specific language meaning that it is only used for structured or relational databases unlike C++, C# whose application is broad. This means that we can only use SQL in the relational database model. SQL is also a declarative language i.e. we just need to declare what to do not how to do it, unlike procedural language which requires the answer for what to do and how to do it.  Here in SQL, we use different types of keys like primary key, foreign key, and also different types of constraints that help us to create and apply rules in the database. We also have different types of operators i.e. like, in, between, not in, exist, etc. We also have different clauses like distinct, order by, group by, from having, etc. Also, we have different aggregate functions like average, count, etc. SQL also provides the functionality of joints and nested query. Like in a nested loop we create a loop inside another loop in the nested query we create a query inside another query.