SQL (Structured Query Language) Introduction

In order to become familiar with SQL and SQL-based platforms, one have to gain basic knowledge about some of the basic concepts. Here I will list what seems to be to be important to know before jumping to learn any SQL-based platform. These concepts helps you to have a big picture about what you are about to learn and why you need to use them. Of course, I might change this list over the time as I myself gain more and more experienced in teaching SQL. For some the following concepts I have written a small description and for others I don't; anyway, this is to provide a checklist for your start point, not to provide you with extensive definitions. I'm sure you can find many comprehensive definitions using search engines and generative AI tools.

Important basic have-to-knows before learning SQL:

1. What are Database?

2. What is a Relational Database?

3. What is SQL (Structured Query Language)?

4. What are the most popular SQL-Based Databases?

   • MySQL:Fast and scalable, Commercial Open Source.

   • Oracle: Commercial, Enterprise-Scale.

   • MariaDB: Open Source.

   • PostgreSQL: Opensource.

   • Some other smaller projects like: SQLite, HSQL, ...

5. What does CRUD (Create, Read/Select, Update, Delete) mean?

   The four basic actions that one can do using databases are:

   • Creating/Inserting Data

   • Read/Select some Data

   • Update Data

   • Delete Data

6. In a Relational Database, what does a Database represent?

   It contains one or more tables.

7. In a Relational Database, what does a Relation/Tuple represent?

   It contains tuples and attributes.

8. In a Relational Database, what does a Tuple/Row represent?

   a set of fields which generally represent an "Object", like a person or a music track

9. In a Relational Database, what does an Attribute/Column/Field represent?

   One pf the possible many elements of data corresponding to the object represented by the row

   

10. What is a Database Schema?

11. What is the SQL Architecture? How SQL commands are run on a SQL Server (regardless of what kind of SQL Client and/or Server you are using)?