mysql - Updating intersection tables, alternative to delete->insert -

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i hope 1 more sql wise can me. suppose following table , relationships they're compacted.

 orders(pk_refno,customer, status) order_accessories(pk_refno,pk_acc) accessories(pk_acc,name,desc)

as can see typical 1:*----*:*----*:1 scenario the issue or concern when updating, accessories each order has can modified, meaning user can add/remove accessories.

the way i've thought using mysql delete accessories , insert updated ones.

i dislike way. think there's sql way it. maybe can suggest , advanced query (which i'll study of course)

the other way thought to:

  • retrieve originals.
  • compare them , remove/add differences.

    i'm not fan of either because done in app, not in database.

    • let's table starts this.

    order_accessories pk_refno  pk_acc 1         73 1         74 1         75 1         86 1         92

    let's 75 supposed 76. assuming sane user interface, user can change 75 76. sane user interface send statement dbms.

    update order_accessories set pk_acc = 76 (pk_refno = 1 , pk_acc = 75);

    if 75 not supposed there in first place, user delete 1 row. sane user interface send statement dbms.

    delete order_accessories (pk_refno = 1 , pk_acc = 75);

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