Which of the following scenarios best justifies the use of a data relationship (Noodles) over a physical join?
Trap 1: When you need to perform a strict inner join
If a strict inner join is required to force data dropping based on missing keys, a physical join remains the appropriate choice. Relationships act more like 'on-demand' joins that preserve all data from the related tables, which may not always align with the strict requirements of an inner join.
Trap 2: When you need to physical merge two tables into a single extract
Physical joins physically merge tables into a single result set in the extract. If the goal is a permanent, static merger at the storage level, physical joins are the correct tool. Relationships keep tables logically separate, which is more flexible but does not result in a single merged table.
Trap 3: When you want to remove unmatched rows from the primary table
Relationships perform a 'left join' behavior by default that preserves rows even when no match exists, unless filter logic is applied. If the requirement is to explicitly remove rows that don't have matches, a physical join is required to enforce that specific exclusion behavior at the query level.
- A
When you need to perform a strict inner join
Why it fails: If a strict inner join is required to force data dropping based on missing keys, a physical join remains the appropriate choice. Relationships act more like 'on-demand' joins that preserve all data from the related tables, which may not always align with the strict requirements of an inner join.
- B
When combining tables with different levels of granularity
Relationships are designed to handle different levels of detail effectively. Because they perform joins only when needed during analysis, they prevent the data duplication issues that occur when joining a high-level summary table to a granular transaction table, ensuring that metrics remain accurate at their appropriate levels.
- C
When you need to physical merge two tables into a single extract
Why it fails: Physical joins physically merge tables into a single result set in the extract. If the goal is a permanent, static merger at the storage level, physical joins are the correct tool. Relationships keep tables logically separate, which is more flexible but does not result in a single merged table.
- D
When you want to remove unmatched rows from the primary table
Why it fails: Relationships perform a 'left join' behavior by default that preserves rows even when no match exists, unless filter logic is applied. If the requirement is to explicitly remove rows that don't have matches, a physical join is required to enforce that specific exclusion behavior at the query level.