MySQL

Hello,

i have one table that has 10 primary keys

and a second table that has 5 primary keys

a third table does the mapping between those two tables

how do i ensure that the 10 primary keys of the first table are inserted ONLY ONCE and not repeatitidly to the third table?

thank you

make them primary key or unique key in the 3rd table

Table 1: Table 2:

110 555
111 666
112 777
.
.
.
.
130

i want the table 3 to be inserted randomly with those keys and the resulting output to be

555 -> 111, 115, 116, 118
666 -> 112, 113, 119,130
.....
......

but the problem is that the key from table 1 are being re-entered because the key from the second changes as well.

should i put a PK to the third table?

thank you