Using the business rules listed below construct and ERD diagram using Microsoft visio tool

Business rules

Every Customer can have more than one Device. Every Device can have only one OS. A Customer may have more than one Support Case. Every Customer may have more than one Mobile Application. A Support Case is created for one Customer and is assigned to one Staff. A Staff member may have multiple support cases A Mobile Application can have several versions. When multiple cases are open for the same issue a Support Case can be a master case that is used to group the duplicate Support Cases from other Customers. When the issue is required to be escalated to Engineering a software patch is then requested. A Support Case can be escalated to Engineering for patch/version to be created. A Customer can create a Support case by Email or a Webform. Once a Support Case is generated a Tier One staff member Categorizes the Support Case and assigns the Support Case to a Staff member.If the person working on the issue is unable to resolve the problem it gets escalated to Engineering group for the application. A Support Case can have only one Category, App, and Type of Issue.

Entity

Customer - FName,LName, Email (may have more than one), ID ,Address

Device ID - Type Manufacturer Model OS Version of OS

Mobile Application - ID, Name,Version, Status, Supported OS

Staff - ID, FName, LName, GroupID

Groups - ID, Name,

Support Case - ID, CustomerID, GroupID ,DeviceID, MobileAppID ,Description of Problem, Date Opened, Date Closed, Status ,Attachments (more than one), Urgency ,IsMaster MasterCaseID, StaffID ,Category (Lifestyle, Health, Games) App (Name of Apps) Type of Issue (Navigation, Crash, Installation)

SLA -ID, Level, Support, Urgency