7. The working process of the bank savings management system is roughly as follows.
Bank deposit types are divided into fixed-term and demand deposits, and fixed-term deposits are divided into 3 months, 6 months, 1 year, 3 years, and 5 years. Different deposit types have different interest rates. When depositing money, depositors must fill in the deposit slip (name, date, deposit type, amount, etc.), and the salesperson will enter the data into the system. The system finds out the deposit interest rate based on the deposit type and stores the data in the database. Depositors must fill out a withdrawal form when withdrawing money. The system searches the depositor's account number from the database and processes the withdrawal. If all deposits are withdrawn, the system will cancel the account. Deposit or withdrawal operations require the depositor to process a voucher.
Based on the above situation, draw the data flow diagram of the system.
The data flow diagram is as follows:
