miniCRM

Company.java

class Company {
   public int id;
   public String name;
}

Company2.java

class Company {
	public int id;
	public String name;
	public List<Contact> contacts;
}

class Contact {
	public int contactId;
	public int companyId;
	public String name;
	public String email;
	public String phoneNumber;
}

Company3.java

class Company {
	public int id;
	public String name;
	public List<Contact> contacts;
	public List<Engagement> engagements;
}

class Engagement {
	public int engagementId;
	public int companyId;
	public String name;
	public String description;
	public Date startDate;
	public Date finishDate;
}

Company4.java

class Company {
	public int id;
	public String name;
}

class Engagement {
	public int engagementId;
	public int companyId;
	public String name;
	public String description;
	public Date startDate;
	public Date finishDate;
}

class Contact {
	public int contactId;
	public int companyId;
	public String name;
	public String email;
	public String phoneNumber;
}

Composition.java

class CompanyWithContacts {
	public Company company;
	public List<Contact> contacts;
}

class CompanyWithContactsAndEngagements {
	public Company company;
	public List<Contact> contacts;
	public List<Engagement> engagements;
}