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hard_deletes

Available from dbt v1.9 or with Versionless dbt Cloud.

snapshots/schema.yml
snapshots:
- name: <snapshot_name>
config:
hard_deletes: 'ignore', 'invalidate', or 'new_record'
dbt_project.yml
snapshots:
<resource-path>:
+hard_deletes: "ignore", "invalidate", or "new_record"
snapshots/<filename>.sql
{{
config(
unique_key='id',
strategy='timestamp',
updated_at='updated_at',
hard_deletes='ignore', 'invalidate', 'new_record'
)
}}

Description

Use the hard_deletes configuration to track hard deletes by adding a new record when row become "deleted" in source. Replaces the invalidate_hard_deletes config to give you more control on how to handle deleted rows from the source.

 When to use the hard_deletes and invalidate_hard_deletes config?
warning

If you're updating an existing snapshot to use the hard_deletes config, dbt will not handle migrations automatically. We recommend either only using these settings for net-new snapshots, or arranging an update of pre-existing tables before enabling this setting.

Default

By default, if you don’t specify hard_deletes, it'll automatically default to ignore. Deleted rows will not be tracked and their dbt_valid_to column remains NULL.

The hard_deletes config has three options:

FieldDescription
ignore (default)No action for deleted records.
invalidateBehaves the same as the existing invalidate_hard_deletes=true, where deleted records are invalidated by setting dbt_valid_to.
new_recordTracks deleted records as new rows using the dbt_is_deleted meta field when records are deleted.

Impact on snapshot records

  • Backward compatibility: The invalidate_hard_deletes config is still supported for existing snapshots but can't be used alongside hard_deletes.
  • New snapshots: For new snapshots, we recommend using hard_deletes instead of invalidate_hard_deletes.
  • Migration: If you switch an existing snapshot to use hard_deletes without migrating your data, you may encounter inconsistent or incorrect results, such as a mix of old and new data formats.

Example

snapshots/schema.yml
snapshots:
- name: my_snapshot
config:
hard_deletes: new_record # options are: 'ignore', 'invalidate', or 'new_record'
strategy: timestamp
updated_at: updated_at
columns:
- name: dbt_valid_from
description: Timestamp when the record became valid.
- name: dbt_valid_to
description: Timestamp when the record stopped being valid.
- name: dbt_is_deleted
description: Indicates whether the record was deleted.

The resulting snapshot table contains the hard_deletes: new_record configuration. If a record is deleted and later restored, the resulting snapshot table might look like this:

iddbt_scd_idStatusdbt_updated_atdbt_valid_fromdbt_valid_todbt_is_deleted
160a1f1dbdf899a4dd...pending2024-10-02 ...2024-05-19...2024-05-20 ...False
1b1885d098f8bcff51...cancelled2024-10-02 ...2024-05-20 ...2024-06-03 ...True
1b1885d098f8bcff53...shipped2024-10-02 ...2024-06-03 ...False
2b1885d098f8bcff55...active2024-10-02 ...2024-05-19 ...False

In this example, the dbt_is_deleted column is set to True when the record is deleted. When the record is restored, the dbt_is_deleted column is set to False.

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