how avoid dublicate data to mysql

Question

I write the code to scrap car info(title, make, model, transmission, year, price) data from ebay.com and save in the mysql, I want if all row\'s(title, make, model, ...) item\'s

Answer 1

declare the primary key as all the columns in the table. See: https://www.mysqltutorial.org/mysql-primary-key/

Answer 2

You could save the result of this query into a variable

SELECT COUNT(*) FROM car_info WHERE Title = <titleValue>, Maker = <makerValue>, Model = <modelValue>, Transmission = <transmisionValue>, Year = <yearValue>, Price = <priceValue>

and then, if the value of the variable is

• 1, you skip the INSERT because you already have this entry in the table
• 0, you make the INSERT because you do not have that entry in the table

It's just one way of doing this.

Answer 3

One option uses not exists:

insert into car_info (title, maker, model, transmission, year, price) 
select v.*
from (select %s title, %s maker, %s model, %s transmission, %s year, %s price) v
where not exists (
    select 1
    from car_info c
    where 
        (c.title, c.maker, c.model, c.transmission, c.year, c.price)
         = (v.title, v.maker, v.model, v.transmission, v.year, v.price)
);

But it would be simpler to create a unique key on all columns of the table, like:

create unique index idx_car_info_uniq
    on car_info(title, maker, model, transmission, year, price); 

This prevents any process from inserting duplicates in the table. You can elegantly ignore the erros that would otherwise have been raised with the on duplicate key syntax:

insert into car_info (title, maker, model, transmission, year, price) 
values (%s, %s, %s, %s, %s, %s)
on duplicate key update title = values(title);