Content
- SQL Definition
- What is SQL used for?
- The advantages of SQL
- Disadvantages
- The main SQL statements
SQL definition
Let’s get very academic for once and start with the definition of SQL: SQL stands for Structured Query Language. Okay with that, you know more but I’m not sure you understand what we’re talking about.
So let’s try to see what exactly it is.
A little reminder about databases. If you have read articles about databases (what is a database? and how does a database work?), you will have understood that the easiest way to store data is to use a Database Management System (DBMS). ).
The data is stored in a structured way and is the basic engine that is responsible for recording and making the data available. Therefore, it is the system (engine) that will manage the reading and writing. Therefore, you just have to tell the engine what to do and it takes care of everything.
What is SQL used for?
As in life, for people to understand each other, they have to speak the same language and well, in computing, it’s the same.
In order for the different programs and the database engine to understand each other, they use a language called SQL.
This language includes all the functionalities that any database administrator needs. You can use it for:
- read the data
- record data
- change data
- Delete data
- It will also allow you to modify the structure of the database: Add tables, Change tables, delete them.
- Add or remove users, manage user rights.
- Manage databases: create new ones, modify them, etc…
As you can see, there are endless possibilities.
This language is structured (as its name suggests), which means that the syntax is always the same and follows very precise rules.
The advantages of SQL
As we saw earlier, one of the main interests of SQL is portability. This means that software that uses a database can work with any database. All you have to do is tell it which database to connect to.
The big advantage is that if for some reason the database needs to be changed, all you have to do is change the relationship between the software and the database. And that’s it!
As a recommendation for any computer science student I can say that:
Due to its use in so many databases today, a good knowledge of SQL is often a great asset on a resume. Another advantage is that SQL is a language in its own right, so there are specific training courses and a specialist in SQL you can integrate very well a team of developers who program in different programming languages.
Disadvantages
The main disadvantage is that you have to learn a language again to use SQL correctly.
Another disadvantage, but not directly related to SQL, is that some code editors (IDEs) do not hesitate to offer different versions of SQL from the standard to provide new features or to be as close as possible to your database. This has the effect of decreasing portability between the software and the databases. (Portability is the fact of being able to interchange certain parts of a system: the software or the database).
The main SQL statements
The main statements of the SQL language are the following:
- select
- UPDATE
- DELETE
- CREATE
- ALTER
- DROP
- COOMIT
- ROLLBACK