# Data Description

This file defines the tables available for synchronization and analysis.
Copy this file to `data_description.md` and customize for your data sources.

## Tables

```yaml
# Folder mapping: data source bucket -> local folder name
folder_mapping:
  "in.c-example": "example"

tables:
  - id: "in.c-example.customers"
    name: "customers"
    description: "Customer master data"
    primary_key: "id"
    sync_strategy: "full_refresh"

  - id: "in.c-example.orders"
    name: "orders"
    description: "Order transactions with line items"
    primary_key: "id"
    sync_strategy: "incremental"
    incremental_window_days: 7
    partition_by: "created_at"
    partition_granularity: "month"
```

## Sync Strategies

- **full_refresh**: Downloads entire table on each sync. Best for small reference tables.
- **incremental**: Downloads only new/changed rows based on a date column. Best for large transactional tables.

## Partition Granularity

When using `partition_by`, data is split into separate Parquet files by time period:
- **month**: One file per month (e.g., `orders/2024-01.parquet`)
- **day**: One file per day (e.g., `events/2024-01-15.parquet`)
- **none**: Single file (default)