[Solved] Consider this dbt merge config snippet:merge: unique_key: ['id']But the source data has duplicate id values. What is the likely issue? | dbt

dbt - Incremental Models

Consider this dbt merge config snippet:

merge:
  unique_key: ['id']

But the source data has duplicate id values. What is the likely issue?

AMerge will fail or produce incorrect results due to non-unique keys

BMerge will ignore duplicates and update only one row

CMerge will create new columns for duplicates

DMerge will automatically remove duplicates before merging

Step-by-Step Solution

Solution:

Step 1: Identify problem with non-unique keys in merge
Unique_key must uniquely identify rows. If duplicates exist, dbt cannot correctly match rows.
Step 2: Understand merge behavior with duplicates
Duplicates cause merge to fail or produce wrong updates because dbt doesn't know which row to update.
Final Answer:
Merge will fail or produce incorrect results due to non-unique keys -> Option A
Quick Check:
Non-unique keys cause merge failure = A [OK]

Quick Trick: unique_key must be unique; duplicates cause merge errors [OK]

Common Mistakes:

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