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