Shashi K. Gadia      Sunil S. Nair

The time format

We suggest the use of instants 0, 1, ..., NOW instead of dates. This avoids unnecessary distaraction.

Identifiers

For better readability We suggest relation names start with lower case characters and attribute names start with upper case characters.

Database instance

The database instance needs improvement. It should also be listed in a tabular format.

Taxonomy

We do not endorse the taxonomy proposed in the main body of this document. We feel it trivializes the issues and is a major distraction. This does not mean that we ourselves have a taxonomy which would be acceptable to all. In our experience in temporal databases, we have learnt some rules of thumb, and that is all. Similarly, others may have their rules of thumb. Giving these rules of thumb a coherent form is desirable, but will be a challanging task. The basis of such a taxonomy should be in structure of English (a natural language). Instead, the proposed taxonomy already assumes the temporal query languages to have a specific form.

Important questions

  1. Are and, or and not of English handled symmetrically?
  2. How is [[r]] of our model incorporated in other models?
Queries

We would like the following queries to be included in the benchmark. The queries are natural queries that might be asked against a temporal database. Some of the queries bring out the features mentioned above under ``Imporatant Questions''.

  1. Give history of employees who have worked in the Toy or Book department.
  2. Give history of employees who worked in the Toy and Book department.
  3. Give Name and Salary history of employees during the time that DI was working.
  4. Give Name and Salary history of employees during the time that DI was not working.
  5. Give salary history of employees who were working at least during 1/1/87 to 31/12/89.
  6. Give managers of John.
  7. What were the departments that had managers at least during 1/1/87 to 31/12/87?
  8. Who were the managers at least during 1/1/87 to 31/12/87 and what departments did they manage?
  9. Give information about employees during the time there was someone managing any department.
  10. Give information from the Emp relation if there were employees at least during 1/1/86 to 1/1/87.