how to deal with fields with unique indexes in the case of sub-tables?
there is no guarantee of constraints when adding new ones
how to deal with fields with unique indexes in the case of sub-tables?
there is no guarantee of constraints when adding new ones
introduces a practice: using a summary table, similar to table_name_increment, insert the summary table before the data is entered into the sub-table, get the id, and record the id in the sub-table.
there are several solutions learn
topic description at present, there is a product that the user places an order to reduce inventory, the order is cancelled to increase inventory, and the backend modifies the inventory quantity. There are three different ways to do this. How about S...