The Repositories area in Evoke is where you define the actual, physical, back end databases that will be accessed and used by the App. These may be via direct access, via stored procedures or through an intermediate API, it is entirely up to you.
For each Repository (database) that you want your App to have access to, you simply set up a Repository definition. Then identify the type of database as either a) SQL b) MultiValue or c) a Custom Data Environment. After this, you simply select the 'flavour' of the database e.g. SQLServer, MySQL, Oracle, etc for SQL or jBASE, Universe, D3, mvBASE, etc for MultiValue.
Evoke will then ask you to select the 'Connection Type" you want to use to connect to the database, this will also identify the actual physical location of the database and address the security requirements to access. The connection type is dependent on the flavour of the database. Examples of the connectivity products are Dymanic DML using ADO.Net or ODP.Net client libraries/Stored Procedures for SQL or mv.Net Core Objects/U2 data client library for MultiValue.
In order for the client libraries to gain access to the databases your DBA will need to provide the 'Connection String', which is also entered here and finally, if your database, uses a prefix for repositiory objects, this is also entered.
Connecting and Scanning your database
When your Repository record is set up, you can use the "Scan" option in Evoke to check connectivity and scan for any repository objects (tables/files) that it finds in the repository.

You can set up as many repository definitions, with connectivity to different databases, as you wish within each Evoke App.