Phones and SIMS table
A table 


You have two types of entity so almost certainly need two tables to model them. As the relationship is one-or-zero-to-many from the SIM side it should have a nullable foreign key to the phone table. Something like

Sim                  
============         Phone
ID      (PK)         =======
inPhone (FK)  ----&gt;  ID (PK)


That way a SIM is either in a phone or floating. If you want to enforce the maximum number of SIMs in each phone at the schema level you'll need custom check constraints or triggers.