Script/workflow insert not exist and auto increment - mysql

Question

I create a script/workflow exportation/importation from 2 system.
I have Table1 {id, name, description}
I want to create a script (not a procedure). I could (I didnt succed) adding procedure into my workflow. (create and delete at the end)
id is auto increment
I cant change the table
I can be sure that between the time I start execution of my script and the end, there will not be an insertion of one of my items into the database.
The script insert {name,description} but I want to NOT insert if the element (name or name and description) is there.
BASE QUERY :
INSERT INTO TABLE1 (name,description) VALUES ('itemX','this is item X')
BASE Script :
Use database1;
BEGIN;
SELECT * FROM TABLE1 ;
SELECT * FROM TABLE3 ;
INSERT INTO TABLE1 (name,description) VALUES ('itemX','this is item X');
set #idTable1 = LAST_INSERT_ID();
INSERT INTO TABLE3 (idTable1,idTable2) VALUES (#idTable1,1);
INSERT INTO TABLE3 (idTable1,idTable2) VALUES (#idTable1,2);
SELECT * FROM TABLE1 ;
SELECT * FROM TABLE3 ;
ROLLBACK;
I want to protect the multiple insertion on TABLE1. But without changing the table.
Maybe I did it wrong
I tried IF but not working outside procedure.
I tried IGNORE (valid only if id is the same, but never the same, its
auto increment)
I tried WHEN
I tried ON DUPLICATE KEY
Because of #idTable1, I will need change the " set #idTable1 = LAST_INSERT_ID();" if I doesnt have if else. But if my item is the only one with the same "name", I can get this instead of last_insert_id.
I opted for creating procedure before my "BEGIN" and removed them at the end of the script.

Answer 1

Just create the table with name as primary key, then be sure that you take care of the key capitalization (uppercase or lowercase) to avoid duplicates.
CREATE TABLE TABLE1(
id INT AUTO_INCREMENT,
name CHAR(30),
description CHAR(100),
PRIMARY KEY (name)
)

Answer 2

create unique constraint on name field if possible.
Otherwise, create trigger before insert in order to ignore duplicate insertion.
Trigger for checking duplicate on two fields a and b:
delimiter //
drop trigger if exists aborting_trigger //
create trigger aborting_trigger before insert on t
for each row
begin
set #found := false;
select true into #found from t where a=new.a and b=new.b;
if #found then
signal sqlstate '45000' set message_text = 'duplicate insert';
end if;
end //
delimiter ;
The trigger here provides feature similar to unique constraint. After creation you should use INSERT IGNORE or INSERT ...ON DUPLICATE KEY UPDATE