Inspect and normalize both databases, then integrate them to draw a reconciled schema. If you zoom in images should be clear.

A help desk hinges on the concept of call, meant as a contact made by a customer to report a problem or a comment about a product he bought. The help-desk service includes a front-end where operators take the customer calls, and a back-end where some experts try to solve the problems. The customer opens the contact by calling the front-end. If possible, the front-end directly manages the problem and gives a solution to the customer, otherwise he hands the problem to an expert. During its lifetime, a call can be overtaken by different persons and groups, but in the end its solution will always be communicated to the customer by a front-end operator. Every activity carried out during a call gives rise to a call detail, so the story of a call can be reconstructed by orderly browsing its details. The problems managed by the help desk are classified into a recursive subject hierarchy. CALLS_DB The unary association among subjects models a tree hierarchy. For every call, the employee who opens it and the one who closes it are modeled. All the passages taking place between the call opening and closing are modeled by actions associated to call details. Each call detail is associated to the employee and the group that manage it. Subjects, as well as calls and enterprises, have a priority; the priority of a call is not necessarily determined by the one of its subject or enterprise. works for GROUP -belongs to GroupCode Location EMPLOYEE *EmployeeCode First Name Last Name Job PERSON * PersonCode First Name Last Name Telephone creates ENTERPRISE * EnterpriseCode Name Address city CUSTOMERS_DB For every customer, the department where he works and the one he bills to are distinguished. CONTRACT CUSTOMER COMPANY *Contract Code *Customer Code Price *Company Code FirstName Agent Name StartDate Address LastName Address EndDate City City Type includes manages makes closes opens of CALL CALL PRIORITY *Callcode 2 DETAIL *Callcode * Sequence Number Duration Comments has -of-04 status * PriorityCode Description made of openingDate in Value works in Type specializes into CITY DEPARTMENT related to is associated to + *CityCode Name State ACTION SUBJECT * Company Code *Dept Code Name Address City Manager *Subject Code o Description *ActionCode Description Type -bills to Inspect and normalize both databases, then integrate them to draw a reconciled schema. A help desk hinges on the concept of call, meant as a contact made by a customer to report a problem or a comment about a product he bought. The help-desk service includes a front-end where operators take the customer calls, and a back-end where some experts try to solve the problems. The customer opens the contact by calling the front-end. If possible, the front-end directly manages the problem and gives a solution to the customer, otherwise he hands the problem to an expert. During its lifetime, a call can be overtaken by different persons and groups, but in the end its solution will always be communicated to the customer by a front-end operator. Every activity carried out during a call gives rise to a call detail, so the story of a call can be reconstructed by orderly browsing its details. The problems managed by the help desk are classified into a recursive subject hierarchy. CALLS_DB The unary association among subjects models a tree hierarchy. For every call, the employee who opens it and the one who closes it are modeled. All the passages taking place between the call opening and closing are modeled by actions associated to call details. Each call detail is associated to the employee and the group that manage it. Subjects, as well as calls and enterprises, have a priority; the priority of a call is not necessarily determined by the one of its subject or enterprise. works for GROUP -belongs to GroupCode Location EMPLOYEE *EmployeeCode First Name Last Name Job PERSON * PersonCode First Name Last Name Telephone creates ENTERPRISE * EnterpriseCode Name Address city CUSTOMERS_DB For every customer, the department where he works and the one he bills to are distinguished. CONTRACT CUSTOMER COMPANY *Contract Code *Customer Code Price *Company Code FirstName Agent Name StartDate Address LastName Address EndDate City City Type includes manages makes closes opens of CALL CALL PRIORITY *Callcode 2 DETAIL *Callcode * Sequence Number Duration Comments has -of-04 status * PriorityCode Description made of openingDate in Value works in Type specializes into CITY DEPARTMENT related to is associated to + *CityCode Name State ACTION SUBJECT * Company Code *Dept Code Name Address City Manager *Subject Code o Description *ActionCode Description Type -bills to Inspect and normalize both databases, then integrate them to draw a reconciled schema