THE ASSERTED VERSIONING GLOSSARY - Managing Time in Relational Databases - page 401

Semantics: P 1 is [during] P 2 if and only if the first clock tick in P 1 is later than the
first clock tick P 2 , and the last clock tick in P 1 is earlier than the last clock
tick in P 2 .

Allen relationship, [during 1 ]
Mechanics: P 1 is [during 1 ]P 2 if and only if (eff_beg_dt 1 < eff_beg_dt 2 ) AND
(eff_end_dt 1 > eff_end_dt 2 ).
Semantics: P 1 is [during 1 ]P 2 if and only if the first clock tick in P 1 is earlier than
the first clock tick in P 2 , and the last clock tick in P 1 is later than the last clock
tick in P 2 .

Allen relationship, [ ]

Mechanics: P 1 [ equals ]P 2 if and only if (eff_beg_dt 1 ¼ eff_beg_dt 2 ) AND
(eff_end_dt 1 ¼ eff_end_dt 2 ).
Semantics: P 1 [ equals ]P 2 if and only if they both start and end on the same clock
tick.

equals

Allen relationship, [ excludes ]
Mechanics: P 1 [ excludes ] P 2 if and only if (eff_end_dt 1 <¼ eff_beg_dt 2 ).
Semantics: P 1 [ excludes ] P 2 if and only if the next clock tick after P 1 is no later
than the first clock tick in P 2 .

Allen relationship, [ excludes 1 ]
Mechanics: P 1 [ excludes 1 ]P 2 if and only if (eff_beg_dt 1 >¼ eff_end_dt 2 ).
Semantics: P 1 [ excludes 1 ]P 2 if and only if the first clock tick in P 1 is no earlier
than the next clock tick after P 2 .

Allen relationship, [ fills ]
Mechanics: P 1 [ fills ] P 2 if and only if (eff_beg_dt 1 >¼ eff_beg_dt 2 ) AND
(eff_end_dt 1 <¼ eff_end_dt 2 ).
Semantics: P 1 [ fills] P 2 if and only if the first clock tick in P 1 is no earlier than the
first clock tick in P 2 , and the last clock tick in P 1 is no later than the last clock
tick in P 2 .

Allen relationship, [ fills 1 ]
Mechanics: P 1 [ fills 1 ]P 2 if and only if (eff_beg_dt 1 <¼ eff_beg_dt 2 ) AND
(eff_end_dt 1 >¼ eff_end_dt 2 ).
Semantics: P 1 [ fills 1 ]P 2 if and only if the first clock tick in P 1 is no later than the
first clock tick in P 2 , and the last clock tick in P 1 is no earlier than the last
clock tick in P 2 .

Allen relationship, [finishes]
Mechanics: P 1 [finishes] P 2 if and only if (eff_beg_dt 1 > eff_beg_dt 2 ) AND
(eff_end_dt 1 ¼ eff_end_dt 2 ).
Semantics: P 1 [finishes] P 2 if and only if the first clock tick in P 1 is later
than the first clock tick in P 2 , and the two time periods end on the same
clock tick.

Allen relationship, [finishes 1 ]
Mechanics: P 1 [finishes 1 ]P 2 if and only if (eff_beg_dt 1 < eff_beg_dt 2 ) AND
(eff_end_dt 1 ¼ eff_end_dt 2 ).
Semantics: P 1 [finishes 1 ]P 2 if and only if the first clock tick in P 1 is earlier
than the first clock tick in P 2 , and the two time periods end on the same
clock tick.