Backends are a part of the Storage Libary (StoreLib). The IDataRecordStorage and IDataTableStorage classes formalize interfaces of backends from the DataRecord and DataTable families, respectively. Backends can be instantiated either via their factories of via abstract factories, DataRecordFactory / IDataRecordFactory and DataTableFactory / IDataTableFactory. Both abstract factory interface classes expose a single method, CreateInstance, with similar signatures:

IDataRecordFactory

Public Function CreateInstance(ByVal Model As DataRecordModel, _
                               ByVal ConnectionString As String, _
                               ByVal TableName As String) As IDataRecordStorage
End Function

IDataTableFactory

Public Function CreateInstance(ByVal Model As DataTableModel, _
                               ByVal ConnectionString As String, _
                               ByVal TableName As String) As IDataTableStorage
End Function

The first argument should be self-explanatory and is the same for all backends. The meaning and format of the other two arguments vary depending on the backend.

DataRecordWSheet and DataTableWSheet abstract an Excel Worksheet (in the current implementation, only open Excel workbooks are supported). The backends interpret ConnectionString as workbook name and TableName as worksheet name: Application.Workbooks(ConnectionString).Worksheets(TableName)

DataTableCSV abstracts delimiter-separated values text files. The backend interprets ConnectionString as a file path and TableName as file name, possibly including the field separator in the suffix.

DataTableADODB and DataTableSecureADODB backends provide wrappers around the ADODB library. By default, they interpret ConnectionString as an ADODB connection string and TableName as the name of a database table. Additionally, specific database types may have connection string constructors. In the current implementation, only the SQLiteODBC driver has a connection string helper. Backend constructor calls this helper if ConnectionString has a predetermined prefix. The helper strips the prefix and interprets the remaining part of the ConnectionString as a database filename, possibly with a path prefix. Helpers for other database types may be defined similarly.