[Solved] Consider this dbt merge config:merge: unique_key: ['customer_id', 'transaction_date']What is the effect of using a composite unique_key here? | dbt

dbt - Incremental Models

Consider this dbt merge config:

merge:
  unique_key: ['customer_id', 'transaction_date']

What is the effect of using a composite unique_key here?

ARows are matched if either customer_id or transaction_date matches

BRows are matched only if both customer_id and transaction_date match

COnly customer_id is used for matching, transaction_date ignored

DThe merge will fail because composite keys are not supported

Step-by-Step Solution

Solution:

Step 1: Understand composite unique_key behavior
Composite keys require all listed columns to match for row identification.
Step 2: Eliminate incorrect options
Matching on either column or ignoring one is incorrect; composite keys are supported.
Final Answer:
Rows are matched only if both customer_id and transaction_date match -> Option B
Quick Check:
Composite keys require all columns to match [OK]

Quick Trick: Composite unique_key matches rows on all listed columns [OK]

Common Mistakes:

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