I will ask a theoretical question: It is necessary to deal with the correct operation of the mysql database with PHP, I know the basics - I can save, display, etc., but there are some nuances:
- There are related tables - what are the ways to select data from a linked table? THOSE. What is the point of relationships between tables, how is it used in PHP?
- I can not understand how the following should work properly: There is, for example, an Input to which a value should fall from the base, then there is a button by pressing which data from the input should be recorded in the database. Here there are two options: The first request is made to the database - it turns out that there is no data in the database that should get into the input, so it remains empty, then it is changed by pens and when you click on the save button, you must send a request to add a new record (i.e. . Insert into table123 ....). The second is when the data in the database is already there and they are loaded into input, then the input is changed again with pens and the query should already be not for adding a new record and updating the old one (Ie Update ....). How generally to organize such when on the form the whole heap of such inputs?