Handling many one-to-many relationships

[Simon F]

Hi all, I am designing a database where a table has 4 (maybe more in the future) one-to-many relationships with other 4 different tables.
It looks quite hard for me to fetch these data and build an object in my application (PHP) using a join.
The simplest thing would be to fetch the object from the first table and then execute 4 different queries on the 4 tables to assign the results as lists (arrays) to the object.
I'm sure that this is not the best solution. Keep also in mind that I would need to display 20 objects per page: this would be 1 query to fetch the objects plus 20*4 queries for the relationships; 81 sql queries for a page doesn't sound right to me.
A second solution would be to use one large table to store the whole amount of data for each object; but in this case the number of the columns would be very high (about 100) and selecting them without using "*" (which seems very harmful in a production environment) would be almost impossible.
Do you have any suggestion? Any best practice? Thank you in advance for your time.