New columns
Allowed by permissive and additive_only; recorded in schema-change evidence.
Core behavior
Schema policy.
Schema policy controls how much drift is acceptable before a target write. It should become stricter as data moves from raw capture to curated consumption.
Policies
| Policy | Behavior | Typical use |
|---|---|---|
permissive | Allows broad schema movement. | Raw landing and early exploration. |
additive_only | Allows new columns, blocks removals and unsafe type changes. | Silver curated tables. |
strict | Requires source and target schema alignment. | Gold consumption models. |
Examples
schema_policy: additive_only
allow_type_widening: true
delta_properties:
delta.enableChangeDataFeed: "true"
delta.autoOptimize.optimizeWrite: "true"result = ingest(
...,
schema_policy="additive_only",
allow_type_widening=True,
delta_properties={
"delta.enableChangeDataFeed": "true",
"delta.autoOptimize.optimizeWrite": "true",
},
)Change handling
Removed columns
Blocked by curated policies. ContractForge does not automatically drop columns.
Type changes
Blocked unless the change is explicitly considered safe widening and allow_type_widening is enabled.
Control columns
Framework technical columns are ignored when comparing source business schema.
Audit
SELECT target_table, change_type, column_name, previous_type, new_type, changed_at_utc
FROM ops.ctrl_ingestion_schema_changes
ORDER BY changed_at_utc DESC;