Describe how fan and chasm traps can occur in an ER model and how they can be resolved.
What will be an ideal response?
A fan trap occurs where a model represents a relationship between two entity types, but the
pathway between certain entity occurrences is ambiguous. Resolve the fan trap by
restructuring the original ER diagram to represent the correct association between these
entities
A chasm trap occurs where a model suggests the existence of a relationship between entity
types, but the pathway does not exist between certain entity occurrences. A chasm trap may
occur where there are one or more relationships with optional participation. Resolve the chasm
trap by identifying the missing relationship
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Match the following terms to their meanings:
I. Statistical function II. Logical function III. Lookup function IV. Nested function V. Array formula A. used to describe a collection of data such as totals, counts, and averages B. used to find values that are stored in lookup tables C. a function that is placed inside another function D. can perform calculations across multiple items E. used to create formulas that test whether a condition is true or false
To return the value of a cell in a table, you would use the INDEX function ________
Fill in the blank(s) with the appropriate word(s).