Re: Hi! We're a bit stuck while making a database. Could use a bit of advice

[Peter Brawley]

Database design ain't like riding a bicycle, you can't just get on and go, there's semester or more of knowledge you need. Read some primers, eg ...

https://www.artfulsoftware.com/mysqlbook/sampler/mysqled1ch01.html

http://www.artfulsoftware.com/dbdesignbasics.html

and follow up on issues that aren't clear to you.

Minimally you probably need something like ...

clients ( 
  cid unsigned smallint primary key auto_increment, /* read about surrogate keys */
  company_name, 
  ... 
)

operations ( opid unsigned smallint primary key auto_increment, name, basefee decimal(10,2), ... )

clientops ( 
  copid unsigned int primary key auto_increment,
  dt date, 
  hrs time,
  see decimal(8,2),
  cid smallint unsigned,
  opid smallint unsigned,
  foreign key(cid) references clients(cid) on delete cascade on update cascade,
  foreign key(opid) references operations(opid) on delete cascade on update cascade,
)

invoices (
  invid unsigned int primary key auto_increment,
  dt date,
  cid unsigned smallint,
  foreign key(cid) references clients(cid) on delete cascade on update cascade,
   ...
invlineitems ( ...)

payments(  ... etc ... )