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1.7 KiB
Markdown
40 lines
1.7 KiB
Markdown
# Databases
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Before we dive deep into SQL, let's quickly define what a database is.
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The definition of databases from Wikipedia is:
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> A database is an organized collection of data, generally stored and accessed electronically from a computer system.
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In other words, a database is a collection of data stored and structured in different database tables.
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## Tables and columns
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You've most likely worked with spreadsheet systems like Excel or Google Sheets. At the very basic, database tables are quite similar to spreadsheets.
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Each table has different **columns** which could contain different types of data.
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For example, if you have a todo list app, you would have a database, and in your database, you would have different tables storing different information like:
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* Users - In the users table, you would have some data for your users like: `username`, `name`, and `active`, for example.
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* Tasks - The tasks table would store all of the tasks that you are planning to do. The columns of the tasks table would be for example, `task_name`, `status`, `due_date` and `priority`.
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The Users table will look like this:
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```
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+----+----------+---------------+--------+
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| id | username | name | active |
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+----+----------+---------------+--------+
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| 1 | bobby | Bobby Iliev | true |
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| 2 | grisi | Greisi I. | true |
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| 3 | devdojo | Dev Dojo | false |
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+----+----------+---------------+--------+
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```
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Rundown of the table structure:
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* We have 4 columns: `id`, `username`, `name` and `active`.
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* We also have 3 entries/users.
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* The `id` column is a unique identifier of each user and is auto-incremented.
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In the next chapter, we will learn how to install MySQL and create our first database.
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