SharePoint with SQL replication scenario

Some SQL Server 2008 technologies, such as transactional replication, cannot be used with SharePoint Products and Technologies because the replication technology requires that a database have a primary key column on all tables. Before you implement replication technologies, ensure that the technology is supported for both SQL Server 2008 and Office SharePoint Server 2007.

reference: https://technet.microsoft.com/en-us/library/cc298578.aspx