Databases Reference
In-Depth Information
Table 5.4
The Suppliers and Parts Database (Sample Values)—Final Fully Temporal Version, Using Intervals
S_DURING
S#
SNAME
STATUS
CITY
DURING
S1
Smith
20
London
[d04, d10 ]
S2
Jones
10
Paris
[d07, d10 ]
S2
Jones
10
Paris
[d02, d04 ]
S3
Blake
30
Paris
[d03, d10 ]
S4
Clark
20
London
[d04, d10 ]
S5
Adams
30
Athens
[d02, d10 ]
SP_DURING
S#
P#
DURING
S1
P1
[d04, d10 ]
S1
P2
[d05, d10 ]
S1
P3
[d09, d10 ]
S1
P4
[d05, d10 ]
S1
P5
[d04, d10 ]
S1
P6
[d06, d10 ]
S2
P1
[d02, d04 ]
S2
P2
[d03, d03 ]
S2
P1
[d08, d10 ]
S2
P2
[d09, d10 ]
S3
P2
[d08, d10 ]
S4
P2
[d06, d09 ]
S4
P4
[d04, d08 ]
S4
P5
[d05, d10 ]
5.5
Interval Types
Our discussion of intervals in the previous section was mostly intuitive in
nature; now we need to approach the issue more formally. First of all, observe
that the granularity of the interval [d04,d10 ] is days. More precisely, we
could say it is type DATE, by which term we mean that member of the usual
family of datetime data types whose precision is day (as opposed to,
