> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Adding mappings to an existing reference

Updating the reference between the `TradeStore` and the `MarketDataStore` in the `PnL` schema to include a new mapping:

```Java theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
configurator.addReferenceMapping("PnL", "TradeStore", "MarketDataStore", new Pair("TradeLeg","Leg"));
```