BCS allows us to perform operations with external data sources like MS-SQL, MS-Access etc. Create, Read, Update and Delete operation can be performed with BCS in SharePoint. BCS can access external data sources through WCF, Web Service, and OData.
What's new in BCS in SharePoint 2013?
- SharePoint can now connect to OData sources
- SharePoint can receive events from external sources
- External Content types can be now scoped at the application level.
- Support for enhanced REST and Client object model.