Multiple tables to correlate queries----> Delete a certain data when there is a note of their own record

When multiple tables are associated with a query, when one of the fields in a table is defined in another table, it is equivalent to one table being a sub-table of another table, such as a problem that is currently being developed:

This is the problem when deleting the data inside the Sys_user table, because Sys_user (System user) contains the user_id field, and in the other table (which is the child table of Sys_user) (sys_user_role "System User Role Table": Define the System User function menu--->sys_user inside the user_name function) also has user_id;

When confronted with such a situation, the solution is:

1. Query to delete all data from the child table inside the parent table

2. Delete the data from the child table

3. Delete the data inside the parent table

Multiple tables to correlate queries----> Delete a certain data when there is a note of their own record