In DS 2.5.1 you can define a data source.
Menu "Configure - Data sources"
Then in your configuration you can reference the datasource name.
For example you have created datasource named DS_T24
Then in dbs file you can reference it like this:
<data ...>
<config id="t24">
<property name="carbon_datasource_name">DS_T24</property>
</config>
<query id="modifyCustomer" useConfig="t24">
...
</query>
...
</data>