Bank is a entity with ph_no as Multivalued Attribute. and Code as Key
∴ Bank(code,Name,addr,phno) ===> For minimum no.of table i can make code and ph_no as key ( it is 1NF only, so there is no problem with PFD's. )
BankBranch is a entity with Branch_No as Key
∴ Bank_Branch(Branch_No,Bank_Name,addr) ===> Bank_name is derived attribute, therefore no problem, it can represent in one table.
Loan is a entity with Loan_No as Key.
∴ Loan(Loan_No,Amount,type) ===> it can represent in one table.
Loans is a many-to-one relation from Loan Entity Type ( total participation) to Bank_Branch Entity Type ( partial participation ).
it can be merged with Loan Entity Type, then Loan(Loan_No,Amount,type,Branch_No). where Branch_No is a Foreign Key from Bank_Branch Entity Type
Branches is a one-to-many relation from Bank Entity Type ( total participation) to Bank_Branch Entity Type ( total participation).
but note that, it actually have (Code,Branch_No), if you merge it with Bank_Branch Entity Type, then Code Should be a Foregin Key, but in Bank Entity Type, it is neither unique key nor Candidate Key ===> can't merge with Bank_Branch Entity Type.
then can we merge with Bank Entity Type ? yes we can merge it ( due to both side total participation), then Bank Entity type look as
Bank(code,Name,addr,phno,Branch_No ) with code,ph_no and Branch_No combinely as key
