A notebook for the work.

A model-review notebook that records table grain and tests key and join assumptions using small fixtures.

• SQL
• Keys
• Model documentation

A data contract design defining quality checks, affected populations and the response to a failed condition.

• SQL checks
• Constraints
• Quarantine

A batch ingestion protocol with immutable inputs, conflict rules and an explicit replay exercise.

• PostgreSQL
• Transactions
• Batch manifests

A reconciliation method that retains coverage gaps and signed value differences at a declared comparison grain.

• SQL
• Decimal arithmetic
• Time windows