35.2 Create Table

By | October 6, 2021

Creating a Table

To create a table in MySQL, use the “CREATE TABLE” statement.

Make sure you define the name of the database when you create the connection

Example

Create a table named “customers”:
import mysql.connector
mydb = mysql.connector.connect(
  host=”localhost”,
  user=”yourusername“,
  password=”yourpassword“,
  database=”mydatabase”
)
mycursor = mydb.cursor()
mycursor.execute(“CREATE TABLE customers (name VARCHAR(255), address VARCHAR(255))”)
#If this page is executed with no error, you have successfully created a table named “customers”.

Output:
C:\Users\My Name>python demo_mysql_create_table.py

If the above code was executed with no errors, you have now successfully created a table.

Check if Table Exists

You can check if a table exist by listing all tables in your database with the “SHOW TABLES” statement:

Example

Return a list of your system’s databases:
import mysql.connector
mydb = mysql.connector.connect(
  host=”localhost”,
  user=”yourusername“,
  password=”yourpassword“,
  database=”mydatabase”
)
mycursor = mydb.cursor()
mycursor.execute(“SHOW TABLES”)
for x in mycursor:
  print(x)

Output:
C:\Users\My Name>python demo_mysql_show_tables.py
(‘customers’,)

Primary Key

When creating a table, you should also create a column with a unique key for each record.

This can be done by defining a PRIMARY KEY.

We use the statement “INT AUTO_INCREMENT PRIMARY KEY” which will insert a unique number for each record. Starting at 1, and increased by one for each record.

Example

Create primary key when creating the table:
import mysql.connector
mydb = mysql.connector.connect(
  host=”localhost”,
  user=”yourusername“,
  password=”yourpassword“,
  database=”mydatabase”
)
mycursor = mydb.cursor()
mycursor.execute(“CREATE TABLE customers (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255), address VARCHAR(255))”)
#If this page is executed with no error, the table “customers” now has a primary key

Output:
C:\Users\My Name>python demo_mysql_primary_key.py

If the table already exists, use the ALTER TABLE keyword:

Example

Create primary key on an existing table:
import mysql.connector
mydb = mysql.connector.connect(
  host=”localhost”,
  user=”yourusername“,
  password=”yourpassword“,
  database=”mydatabase”
)
mycursor = mydb.cursor()
mycursor.execute(“ALTER TABLE customers ADD COLUMN id INT AUTO_INCREMENT PRIMARY KEY”)
#If this page is executed with no error, the table “customers” now has a primary key

Output:
C:\Users\My Name>python demo_mysql_alter_primary_key.py

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