Chap4 Temporal Database Chap 4: Temporal Extensions to the Relational Model and SQL

Chap4 4.2 Temporal Relational Model (TRM)

Chap4 4.2 Temporal Relational Model (TRM)

Chap Synchronism and Temporal Dependence Here, an Employee gets a raise in salary if and only if he or she gets a promotion, and an employee is never demoted. Thus, the TVA’s Salary and Position form a set of synchronous attributes.

Chap Synchronism and Temporal Dependence Plane# is the identifier of an aircraft, Part is the name of a part, Cond describes the nature of the problem the part has, Place is the name of the place where it is being serviced, Cost is the cost associated with the T s is the time when a particular maintenance event began, and T E is the time when it terminated.

Chap Synchronism and Temporal Dependence

Chap Time Normalization Sal-Mgr (Table 4.3) can be decomposed into two relations, Manager (Table 4.4) and Salary (Table 4.5)

Chap Time Normalization

Chap4 4.3 TSQL: A Language Interface for TRM

Chap4 4.3 TSQL: A Language Interface for TRM

Chap4 4.3 TSQL: A Language Interface for TRM

Chap The WHEN Clause

Chap The WHEN Clause

Chap Retrieval of Timestamps

Chap Temporal Ordering If there are n breaks for a given TIK value, then the tuples can be viewed as having been partitioned into n+1 groups. If breaks are taken into consideration for temporal ordering, the tuples in each of these groups created by the presence of breaks – are given a unique set of ordinal numbers.

Chap Temporal Ordering

Chap Temporal Ordering

Chap The TIME-SLICE Clause

Chap Aggregate Functions and GROUP BY

Chap Aggregate Functions and GROUP BY

Chap The Moving Window

Chap The Moving Window

Chap4 4.4 Temporal Relational Operators

Chap COMPRESS