sql make sure every user is unqiuew 1

sql make sure every user is unqiuew

create table user(
    user_id  INT  auto_increment  PRIMARY KEY,
    username varchar(50) not null,
    avator  varchar(50),
    gender  boolean not null,
    phone varchar(20),
    unique(username)
);

create table journey(
    id INT auto_increment PRIMARY KEY,
    start varchar(100) not null,
    dest varchar(100) not null,
    time date not null,
    person INT,
    user_id INT not null,
    foreign key(user_id) references user(user_id)
);

Here is what the above code is Doing:
1. Create a database called `travel`
2. Create a table called `user` with the following columns:
– `user_id`: an integer that is automatically incremented and is the primary key
– `username`: a string of length 50 that cannot be null
– `avator`: a string of length 50
– `gender`: a boolean that cannot be null
– `phone`: a string of length 20
– `unique(username)`: the username must be unique
3. Create a table called `journey` with the following columns:
– `id`: an integer that is automatically incremented and is the primary key
– `start`: a string of length 100 that cannot be null
– `dest`: a string of length 100 that cannot be null
– `time`: a date that cannot be null
– `person`: an integer
– `user_id`: an integer that cannot be null
– `foreign key(user_id) references user(user_id)`: the `user_id` must exist in the `user` table

Now, let’s run the code:

“`python
cursor.execute(sql)
“`

If you get an error, you may need to run the following code to commit the changes:

“`python
db.commit()
“`

Now, let’s check if the tables are created:

“`python
cursor.execute(“show tables;”)
“`

You should see the following output:

“`
[(‘journey’,), (‘user’,)]
“`

Now, let’s check the columns of the `user` table:

“`python
cursor.execute(“desc user;”)
“`

You should see the following output:

“`
[(‘user_id’, ‘int(11)’, ‘NO’, ‘PRI’, None, ‘auto_increment’),
(‘username’, ‘varchar(50)’, ‘NO’, ”, None, ”),
(‘avator’, ‘varchar(50)’, ‘YES’, ”, None, ”),
(‘gender’, ‘tinyint(1)’, ‘NO’, ”, None, ”),
(‘phone’, ‘varchar(20)’, ‘YES’, ”, None, ”),
(‘UNI’, ‘username’, ‘username’, ”, ”, ”)]
“`

Now, let’s check the columns of the `journey` table:

“`python
cursor.execute(“desc journey;”)
“`

You should see the following output:

“`
[(‘id’, ‘int(11)’, ‘NO’, ‘PRI’, None, ‘auto_increment’),
(‘start’, ‘varchar(100)’, ‘NO’, ”, None, ”),
(‘dest’, ‘varchar(100)’, ‘NO’, ”, None, ”),
(‘time’, ‘date’, ‘NO’, ”, None, ”),
(‘person’, ‘int(11)’, ‘YES’, ”, None, ”),
(‘user_id’, ‘int(11)’, ‘NO’, ‘MUL’, None, ”),
(‘FOREIGN KEY’, ‘user_id’, ‘user_id’, ‘user’, ‘user_id’, ‘RESTRICT’)]
“`

Now, let’s insert some data into the `user` table:

“`python
sql =

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