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If R1 and R2 are two relations or functions, then the result of R3 = R1 × R2 is the combination of tuples that are in R1 and R2. The product is associative and commutative.
Degree (R3) =Degree of (R1) + Degree (R2).
In case, R3 will have tuples such that R3 = {t1 || t2 | R1 ∋ t1 ∧ R2 ∋ t2}.
Example:
R2
A
B
A1
B1
A2
B2
A3
B3
A4
B4
R1
C
C1
C2
R3 = R1 × R2 is
Flights(FlightNo, DeptDateTime, Origin, ArrivalDateTime, Destination, Capacity, SoldSeats) Tickets(FlightNo, Seat, CustID) Where - flightNo is the PK of the flights table - DeptDa
#question.what is mapping constraints and types?.
Define data model? A data model is a collection of conceptual tools for explaining data, data relationships, data semantics and consistency constraints.
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While sorting field groups we cannot use more than one key field False.
assume we have the following apllicationthat model sccer team the games they play and the players inv each teamin the design we want to capture
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