You are given the task of designing a DBMSbased email system. The system will be used to store and access email messages and contact lists for a large collection of users. Your client has specified the following requirements: Each user will have a unique numeric ID. In addition, you need to store the first name, last name, and email address of each user in the system. Each user has a number of contacts. A contact has a first name, a last name, an email address, and one or more phone numbers (where each phone number has a type, e.g., home, cell, etc.). An email message belongs to exactly one user and has a “to” field, a date, a subject field, and a body field. Each email message is stored in exactly one folder. A folder corresponds to a single user and has a name and a parent folder. Every user is either a paying customer or a trial user. Trial users have expiration dates and remaining quota associated with them. Paying customers have no quota but do have a balance associated with them. Draw an ER diagram for this database using as much of the ER model as appropriate.
You are given the task of designing a DBMSbased email system. The system will be used to store and access email messages and contact lists for a large collection of users. Your client has specified the following requirements:
Each user will have a unique numeric ID. In addition, you need to store the first name, last name, and email address of each user in the system.
Each user has a number of contacts. A contact has a first name, a last name, an email address, and one or more phone numbers (where each phone number has a type, e.g., home, cell, etc.).
An email message belongs to exactly one user and has a “to” field, a date, a subject field, and a body field.
Each email message is stored in exactly one folder. A folder corresponds to a single user and has a name and a parent folder. Every user is either a paying customer or a trial user. Trial users have expiration dates and remaining quota associated with them. Paying customers have no quota but do have a balance associated with them.
Draw an ER diagram for this
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