The regular approach is to use External Contenttypes with BCS: http://msdn.microsoft.com/library/jj163139.aspx
This enables you to use External Lists:
An external list enables access to data from external
systems in the same way that SharePoint list data is accessed.
External lists use external content types as their data sources.
External lists enable you to use the metadata that is already defined
about an external content type to create a SharePoint list that has
external data that looks and performs like any other SharePoint list.
You can also take external lists offline to be used in Outlook 2013.
This allows you to work with external data just like native Outlook
Item types, such as Contacts, Tasks, and Posts, and use the external
data in Office client applications. External lists enable writing back
to the external system if the external system allows it, and if it is
modeled accordingly by the external content type. This implies that
users can edit external data directly from within. Any changes that
were made to the items in the list are synchronized automatically with
the external system. Also by using the Refresh data button in the
list, you can synchronize and get updated data from the external
from above link.
This approach will keep a relationship between the SQL data and the list items.
For a full guide to create this from an SQL Source, follow this link: http://msdn.microsoft.com/en-US/library/jj220063.aspx