Configurations do not necessarily need to be of same type. Of course, if you have a datastore for SAP you cannot simply create another configuration for Oracle Apps and expect it work, hence we do not allow those. But relational databases are interchangeable.
Actually, the combination database vendor and database version is the combination considered as each database version might potentially have a different performance characteristic, e.g. bulkloader was fast in the old version now a different load option is available.
So when creating a new configuration for a relational database, you choose the database type and version. As each table loader can have different settings for each configuration, when creating a new one the major question is how to choose the table loader options.
But what options should be used as the defaults for the table loaders? You can simply start with the default values of the table, so no special table loader options set. However, if you do not have any database specific setting used, e.g. no Oracle bulkloader just the flags in the tab for the Options of the table loader, it would be convienent to just copy those. As that is the case here, I want to use the same settings for the new SQL Server configuration as I used for Oracle. So the dataflows loading with autocorrect load will be loaded this way for SQL Server as well, tables loaded with "truncate table" will be truncated in the SQL Server database also, etc. And those dataflows where the Oracle Bulkloader was used, will remain with the defaults.
In order to check for potential problems, DI will show you a list of all dataflows and their table loaders and you can check if you had inconsistancies there like a bulkloader for Oracle enabled that could not be converted to the corresponding SQL Server bulkloader options.
After creating a new configuration, it is a good idea to go through all dataflows and check the settings for the table loader objects for the new vendor/version combination. This was not required in the previous case where we created a new configuration for having a different database connection but still the same database type/version.
So you go through all the dataflows, pick each table loader for this datastore and switch between the database type/version combination to see the options. This is not the visually most intuitive way to present it, hence let me say that more explicitly: All the tabs to the right of the table loader, so Options, Bulk Loader Options, Triggers, ... can be different for each value you pick from this database type drop down box.
So for example the Oracle settings are using the API bulkloader in truncate mode....
...switch to SQL Server...
...and for SQL Server we use its bulkloader settings.