CRUD applications to update MYSQL database

This is a broad topic i think needs more documentation. My question relates to overcoming database constraints without compromising date, security. I have database constraints that disallow my crud from updating table rows i want updated. For instance you cant update the child rows of a database without going to the parent.  I am looking for much more guidance on best practices for crud applications. Is it a good, feasible practice to then call two tables at once weaved together so the crud can update the primary target table? Is it bad practice to run crud application on such tables? Is it a good practice to use a query for the crud application goals instead?  Is it wise to simply turn off all the restrictions? I can restrict the crud to a limited set of forms but i would like to reach more if not all tables, the database restrictions are a major obstacle to that. I see clearly that i can simply skip the problem column in question. I need the freedom to update that column so my administrator section can update the target item. Every crud example i have seen so far fails to reach the desired depth or goes so deep the application becomes unstable. I am ok with one crud application for each table but i would be more happy with one crud application that could handle the diversity of all tables, their specific constraints. If i am to continue with one crud application per table i want to hear back from someone who has been there before.