Walton Resto have decided to split the set-up of the data storage and management from the development of the application processes that will access the data. Two different companies will be involved. One, the data management company will be managing and hosting the data. The second will be responsible for the development and maintenance of the applications that access the data. The data management company, to optimise its use of hardware, will occasionally reorganise the Walton Resto database by moving it to faster hardware, or onto different data storage. The application development company will also be adjusting and adding functionality to the applications over time.

What is a data dictionary? Explain the importance of having a single data dictionary in the development of the Walton Resto system.

Why will a three-schema architecture be beneficial in this situation; where both the data management company and application developers may make the changes described? Explain your answer.