Learn How to Create a Database | First Steps in SQL Tutorial

Learn How to Create a Database | First Steps in SQL Tutorial


I am sure you are now keen to begin to use this
software to organize and manipulate data in practice. Let’s start by creating a database. We will use the ‘Sales’ database. We will show you how to create your own database,
also called schema, starting from scratch. Only in this way can you grasp just how powerful
SQL can be. Therefore, first we will define a database,
and then create the other components, such as tables and fields. We will use the Data Definition Language CREATE
statement to create a database. Quite intuitively, the command we need in
this case is CREATE DATABASE. The syntax to abide by is CREATE DATABASE,
the optional statement [IF NOT EXISTS], the name of the database, and finally, a semicolon. Let’s break down this entire line to understand
the meaning of each element. CREATE DATABASE will obviously create a database
as an abstract unit. This means that for the moment the database
will not contain any data and will simply represent an object ready to be filled with
information. Think of it as creating a canvas on which
you would be able to draw your relational schemas later. IF NOT EXISTS will verify if a database with
the same name exists already. If it does, this will impede us from creating
a database with the same name. The brackets around indicate that the statement
between them is optional in the syntax. Optional means you could either type or omit
the statement. This is the situation with [IF NOT EXISTS]
– even if you don’t include it the code will run anyway. Nevertheless, we advise you to always use
it because it allows you to avoid potential errors when working with large amounts of
data. It is good to build the habit of attaching
this phrase straight after the CREATE statement. Next, we will have to specify the name of
the new database. We strongly suggest you give a name that is
short but at the same time as related to the content of the data as possible. Try to avoid assigning names like “database_01”
or “database_about_sales_in_New_York”. In our case, the data we will work with is
about the customer sales registered in a company. For this reason, we will call the database
“Sales”. Whether you use uppercase or lowercase letters
only, or both – it’s the same for SQL. The SQL code is not case sensitive neither
when assigning names of objects nor when writing queries. Otherwise, in this element the quotes are
optional – you could either say “Sales” within quotes, or without using any quotes. It makes no difference. Finally, you should always end your statements
with the semicolon character. It functions as a statement terminator. Yes, it is often true that your queries will
run properly without it, but this is not the point. In longer scripts, when your code contains
more than a single statement, the semicolon is indispensable. So, please, try to end your statements with
this character – this will not only help you avoid errors sometimes, but will also
improve the readability of your code. Ok! So… I guess we are ready to type down our first
query and run it, aren’t we? Let’s type CREATE DATABASE IF NOT EXISTS,
without brackets, “Sales” (keeping in mind that we are allowed to omit the quotes
without any problem), and semicolon. Now, it is important to note that this entire
line is nothing but a piece of text until you execute it. To execute, or run, a query, you must press
this lightning symbol. The alternative is to implement the shortcut
combination Ctrl, Shift and Enter. So, what are we waiting for? Let’s press this button and see the output
of our work. At first sight, it seems nothing happened. This is not true though. When new databases, schemas, or tables are
created, we always need to refresh the content in the “Schemas” section at the bottom
left part of the screen by pressing this little button here. Ha! The “Sales” database is ready for use! Great! Please, remember that you could have achieved
the same output if you had used CREATE SCHEMA instead of CREATE DATABASE. Considering that database and schema are practically
synonyms, this seems like a logical alternative, right? Well, we just completed our first task – creating
a database. Congratulations! In this video, we will look at the MySQL workbench
interface in more detail as it can help us manage our database better. The symbol located before the name “Sales”
indicates us that the object in question is a database. You’ve seen it before, haven’t you? 😊 It stands for a database. Moreover, by pressing this miniature triangle,
we see how this database can be broken down into four components – Tables, Views, Stored
Procedures, and Functions. Since we have not created any of these for
the moment, nothing will happen if you click any of the respective names. It is important to be familiar with this little
symbol that appears when you hover above the name of the database. It is a feature of the MySQL workbench you
will love when you fill in your database with data. Once you press it, a new tab containing information
about the database will open in the right part of the screen. Although all these fields are currently empty,
when we fill our database with information, we will be able to inspect its tables, columns,
indexes, triggers, views, stored procedures, functions, and grants in a great level of
detail. All right. We just saw how to obtain information about
the “Sales” database and some of its components. However, we don’t know how to tell the computer
that “Sales” is going to be the database we want to apply the SQL code and operations
to. After having created the database, you must
type ‘USE “Sales” semicolon’ in the SQL query editor field. By running this line, you will select the
existing “Sales” database and you will be ready to apply various SQL commands and
data manipulation tasks on it.

Danny Hutson

Leave a Reply

Your email address will not be published. Required fields are marked *