BCS utilizes external content types. Similar to normal content types (which can be metadata columns, properties, and workflows that are applied to a piece of data), an external content type allows you to apply those same concepts to external data. External content types allow the reuse of metadata and actions on external data sources.
External content types can be used to create and represent external data as the following types of objects:
- External lists: External lists are the most common type of object in BCS solutions. External lists use an external content type as their source, allowing you to create a SharePoint list populated with external data. External lists function just like any other SharePoint list, providing a familiar interface to interact with data. External lists, depending on the connected system, may allow you to write back to the source. If configured, users can make changes to content in the external list, which will get synchronized...