The fast, easy and complete integration of external data, e.g. from databases is a common requirement in the use of Microsoft SharePoint technology. Existing solutions, such as the Business Data Catalogue (BDC) for SharePoint 2007 or Sharepoint Business Connectivity Services (BCS) for SharePoint 2010, are often too complex at the facility, don't support "real" SharePoint lists, bring with them limitations or are available for certain SharePoint editions only. The SharePoint Business Data List Connector by Layer2 on the other hand, can easily be done with a few settings to be configured directly in the browser based list settings dialogue - without any additional tools required.

Full list features
The desired data can be presented without any restrictions, with the full read-only (or optionally write back / CRUD with V3.0) functionality of common SharePoint lists made available:
- Views,
- sorting and
- grouping,
- filters can be created as usual,
- lookups are supported,
- calculated columns,
- including notification of changes as RSS or email.
Business actions
Business actions can be very easy implemented using the default SharePoint list-based workflow and notification system. Changed data is updated only, very fast with batch update in background. So, if an external data record is changed, you can have notifications and workflow in SharePoint.
List type features are supported
There is full support for certain list type features, e.g. contacts, tasks, events, KPI-lists etc.
BDC availability
BDC is available for SharePoint Enterprise version only. The BDLC is also available for any SharePoint 2007 version, even for the free Windows SharePoint Services 3.0 (WSS).
BCS availabilty
BCS is available for SharePoint 2007 (all editions) and SharePoint Foundation. While the BCS external list is a great step forward in external data integration with SharePoint, it still has some limitations, that could be important - depending on requirements.
For a feature comparision see here:
http://layer2/en/community/FAQs/BDLC/Pages/Feature-comparision-sharepoint-external-list.aspx
Performance
Attaching external data directly to SharePoint web parts can have performance impacts on the external system, if data is often requested on every page call. The BDLC list, on the other hand, acts as a "cache" for better performance and lower system resources - if data is updated not too often. BDLC can update several 1000 items in just a minute or even seconds - depending on number and type of columns, data source and amount of update/insert/delete operations. Modified items are updated only using the very fast batch update API of SharePoint.
Web Parts
In most cases no web parts are required, bcause you can use the list directly. However, you can use any web part, that can connect to lists without any restrictions.
Migration to SharePoint 2010
While BDC-based solutions are often difficult to migrate from SharePoint 2007 to 2010, BDLC works in the same way with both SharePoint versions. It's very simple to migrate, all connections and settings are kept working. There is a free upgrade available for all customers with Software Assurance (SA).