same id inserting again in a table?

[rashgang]

i have created a table in mysql with primary and auto increment

 

example:

create table sample(id int not null primary key,first_name varchar(30))

 

insert into table sample values(1,'test');

insert into table sample values(2,'test');

 

after delete the first row with id "1". then insert again 1 on the same table it gets inserted

my question we have created the table with primary key how the same id inserted again?

 

[requinix]

Because you deleted the old record and you specifically told MySQL to use id=1 again. If you had an auto_increment column (like your example does not show) and you didn't specify the new id value, MySQL would have used id=3.