# TASK 5.2: Implement Staging Table Catalog And Redshift COPY Command Construction

## Summary

Implement the fixed v1 mapping from emitted `GetOrders` load contracts to Redshift staging tables and the SQL-construction path that turns one contract artifact set into one Redshift `COPY` command.

This subtask is the core warehouse-shaping step for the first `load -> Redshift staging` slice.

## Dependencies

- [TASK 5.1](./TASK5.1.md) - load-to-staging orchestration and upstream normalize-load batch resolution

## Files to Create

### 1. Staging table catalog

Create or finalize the fixed v1 staging table catalog for the narrowed `Sales2.GetOrders` contract set.

Required catalog details:

- `ContractName`
- `TargetTableName`
- schema-version compatibility rules when needed
- whether the contract is required for this stage

### 2. Redshift `COPY` command factory

Create or finalize the component that builds Redshift `COPY` SQL for one target table and one resolved contract artifact set.

Recommended logical service:

- `RedshiftCopyCommandFactory`

## Files to Modify

### 3. Warehouse SQL construction seam

Modify or finalize the shared warehouse SQL seam so staging-load SQL is created from explicit catalog data and centralized Redshift configuration rather than Brink-specific string concatenation spread across orchestration code.

## Required Behavior

- one emitted load contract maps to exactly one staging table
- the fixed catalog covers the narrowed `TASK4.md` `GetOrders` contract inventory only
- `COPY` command construction supports Parquet input
- `COPY` command construction uses explicit target table and S3 artifact locations
- Redshift auth options come from centralized warehouse configuration rather than per-contract branching
- command construction remains independent from execution so it can be unit-tested directly

## Testing

### Unit tests

Add unit tests for:

- contract-to-table catalog correctness for every required v1 contract
- rejection of unknown or unsupported contracts
- `COPY` SQL construction for Parquet input
- target table selection and input URI/prefix selection
- use of centralized auth/config placeholders in generated SQL

## Acceptance Criteria

- [x] Fixed v1 staging table catalog exists for the narrowed `GetOrders` contract set
- [x] Every required contract maps deterministically to one staging table
- [x] Unknown or unsupported contracts are rejected explicitly
- [x] `COPY` SQL can be built for Parquet input from resolved artifact locations
- [x] Unit tests cover mapping and SQL-construction behavior

## Notes

- Keep this subtask focused on mapping and SQL construction.
- Do not execute Redshift commands here; that belongs to `TASK 5.3`.