Some time ago I was looking for something to solve this problem that I have encountered in other systems that I have developed, I would like to know a solution for how to do an auto increment id, but an auto increment related to another field, for example: I have my product table and these products are categorized, so they have a id_categoria , which references the category table and my id of the product table is auto increment , and I have a records in the table of products that would be so by example:
id | id_categoria
1 | 1
2 | 3
3 | 2
4 | 1
5 | 2
6 | 1
7 | 4
...
But I would like this auto increment to only happen with respect to category, for example for the category of id_category I have the product of id 1,2,3,4,5, knowing that I would have to have a key primary compiler, having the product id and the category id as primary keys , my table would look something like this:
id | id_categoria
1 | 1
1 | 2
1 | 3
1 | 4
2 | 1
2 | 2
3 | 1
...
But without first needing to consult the bank and then adding the desired id, something that was automatic done by the bank, does anyone know of any solution to this?