# Frankfurter

[Frankfurter API](https://www.frankfurter.dev/) is an online platform which fetches current and historical exchnge rate data.

omniload supports Frankfurter as a source primarily to demonstrate omniload's features since the API doesn't require any authentication. 

## URI format

The URI format for Frankfurter is as follows:

```text
frankfurter://?base=<currency-code-here>
```

URI parameters:
- `base`: defines the base currency code (e.g. EUR, USD, IDR) used to calculate the exchange rates. 


## Set-Up Frankfurter Integration

Let's say you want to fetch the exchange rates for a certain period with the base currency as Indian Rupees. Here's a sample command that will copy this data into your DuckDB database:

```bash
omniload ingest \
--source-uri 'frankfurter://?base=INR' \
--interval-start '2025-03-20' \ 
--interval-end '2025-03-28' \       
--source-table 'exchange_rates' \    
--dest-uri 'duckdb///frankfurter.duckdb' \
--dest-table 'my_schema.exchange_rates'
```

The result of this command will be a list of currency exchange rates from 20.03.2025-28.03.2025 with INR as the base currency in your DuckDB database. 

## Tables

Frankfurter source allows ingesting the following sources into separate tables:

| Table           | PK | Inc Key | Inc Strategy | Details                                                                                                                                        |
| --------------- | ----------- | --------------- | ------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- |
| [currencies](https://frankfurter.dev/currencies/)  | - | –                | replace               | Retrieves list of available currencies with ISO 4217 codes and names. |
| [latest](https://frankfurter.dev/#rates)    | ["date", "currency_code", "base_currency"] | –                | merge               | Fetches latest exchange rates for all currencies. |
| [exchange_rates](https://frankfurter.dev/#historical-rates) | ["date", "currency_code", "base_currency"] | date    | merge               | Retrieves historical exchange rates for specified date range.|

Use these as `--source-table` parameter in the `omniload ingest` command.


**Notes**:
- The arguments `--interval-start` and `--interval-end` are only relevant for the table exchange_rates.
- If a start date but no end date is specified, then the end date will default to today's date and omniload will retrieve data up until the latest published data.
- Note that the [Frankfurter API](https://www.frankfurter.dev/) only publishes updates Monday-Friday. If the given date is on the weekend, the date will default to the previous Friday.