Chap4

Temporal Database

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

Chap44.2 Temporal Relational Model (TRM)

Chap44.2 Temporal Relational Model (TRM)

Chap4

4.2.1 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 .

Chap4

4.2.1 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 Ts is the time when a particular maintenance event began , and TE is the time when it terminated.

Chap4

4.2.1 Synchronism and Temporal Dependence

Chap44.2.2 Time Normalization

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

Chap44.2.2 Time Normalization

Chap44.3 TSQL: A Language Interface for TRM

Chap44.3 TSQL: A Language Interface for TRM

Chap44.3 TSQL: A Language Interface for TRM

Chap44.3.1 The WHEN Clause

Chap44.3.1 The WHEN Clause

Chap44.3.2 Retrieval of Timestamps

Chap44.3.3 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.

Chap44.3.3 Temporal Ordering

Chap44.3.3 Temporal Ordering

Chap44.3.4 The TIME-SLICE Clause

Chap44.3.5 Aggregate Functions and GROUP BY

Chap44.3.5 Aggregate Functions and GROUP BY

Chap44.3.6 The Moving Window

Chap44.3.6 The Moving Window

Chap44.4 Temporal Relational Operators

Chap44.4.2 COMPRESS