You are a member of database design team for a retail banking system. The system maintains information related to each customer. The customer information includes his/her first name, last name, gender, residential address, mailing address, and social security number. Each customer is given a unique customer number. A customer should have at least one account and can have more than one accounts. Each account is identified by an account number. The system allows two types of transactions on an account. They are withdrawal transactions and deposit transactions. A withdrawal transaction reduces the account balance by the transaction amount. A deposit transaction increases the account balance by the transaction amount. The system does not allow opening a new account without the initial deposit and therefore an account has at least one deposit transaction. The system has a requirement to record all the withdrawals and deposits. Required:
Based on the description above, draw the first level data model diagram that identifies all the entities/classes, attributes/properties for each class/entity, and the relationships between the classes/entities.