[Solved] You wrote this incremental model using delete+insert:{{ config(materialized='incremental', incremental_strategy='delete+insert', unique_key='id') }} select id, value from source_tableAfter running,... | dbt

dbt - Incremental Models

You wrote this incremental model using delete+insert:

{{ config(materialized='incremental', incremental_strategy='delete+insert', unique_key='id') }}
select id, value from source_table

After running, you notice duplicate rows in the target table. What is the likely cause?

AThe incremental_strategy parameter is misspelled

BThe model should use append strategy instead

CThe source_table has duplicate rows causing duplicates

DThe unique_key is missing or incorrect, so delete does not remove all matching rows

Step-by-Step Solution

Solution:

Step 1: Understand delete+insert with unique_key
Delete+insert deletes rows matching unique_key before inserting new data.
Step 2: Diagnose duplicates cause
If unique_key is missing or wrong, delete won't remove all duplicates, causing duplicates to remain.
Final Answer:
The unique_key is missing or incorrect, so delete does not remove all matching rows -> Option D
Quick Check:
Correct unique_key needed for delete+insert to avoid duplicates [OK]

Quick Trick: Always set correct unique_key for delete+insert strategy [OK]

Common Mistakes:

MISTAKES

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