THE ASSERTED VERSIONING GLOSSARY - Managing Time in Relational Databases - page 402

Allen relationship, [ intersects ]
Mechanics: P 1 [ intersects] P 2 if and only if (eff_beg_dt 1 <¼ eff_beg_dt 2 ) AND
(eff_end_dt 1 > eff_beg_dt 2 ).
Semantics: P 1 [ intersects] 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 next clock tick after P 1 is later than the first
clock tick in P 2 .
Allen relationship, [ intersects 1 ]
Mechanics: P 1 [ intersects 1 ]P 2 if and only if (eff_beg_dt 1 >¼ eff_beg_dt 2 ) AND
(eff_beg_dt 1 < eff_end_dt 2 ).
Semantics: P 1 [ intersects 1 ]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 first clock tick in P 1 is earlier than the
next clock tick after P 2 .
Allen relationship, [meets]
Mechanics: P 1 [meets] P 2 if and only if (eff_end_dt 1 ¼ eff_beg_dt 2 ).
Semantics: P 1 [meets] P 2 if and only if the next clock tick after P 1 is the same as
the first clock tick in P 2 .
Allen relationship, [meets 1 ]
Mechanics: P 1 [meets 1 ]P 2 if and only if (eff_beg_dt 1 ¼ eff_end_dt 2 ).
Semantics: P 1 [meets 1 ]P 2 if and only if the first clock tick in P 1 is the same as the
next clock tick after P 2 .
Allen relationship, [ occupies ]
Mechanics: P 1 [occupies] 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 )) AND
NOT((eff_beg_dt 1 ¼ eff_beg_dt 2 ) AND (eff_end_dt 1 ¼ eff_end_dt 2 )).
Semantics: P 1 [ occupies] 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 ,andP 1 and P 2 do not both begin and end on the
same clock tick.
Allen relationship, [ occupies 1 ]
Mechanics: P 1 [ occupies 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 )) AND
NOT((eff_beg_dt 1 ¼ eff_beg_dt 2 ) AND (eff_end_dt 1 ¼ eff_end_dt 2 )).
Semantics: P 1 [ occupies 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 , and P 1 and P 2 do not both begin and end on the same clock tick.
Allen relationship, [overlaps]
Mechanics: P 1 [overlaps] P 2 if and only if
(eff_beg_dt 1 < eff_beg_dt 2 ) AND
(eff_end_dt 1 > eff_beg_dt 2 ) AND
(eff_end_dt 1 < eff_end_dt 2 ).
Semantics: P 1 [overlaps] 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 next clock tick after P 1 is later than the first
clock tick in P 2 , and the last clock tick in P 1 is earlier than the last clock tick in P 2 .
Allen relationship, [overlaps 1 ]
Mechanics: P 1 [overlaps] P 2 if and only if
(eff_beg_dt 1 > eff_beg_dt 2 ) AND
(eff_beg_dt1 < eff_end_dt 2 ) AND