Queued updating replication
If the table is dropped from the publication, the msrepl_tran_version column is not removed.Transactional replication requires a primary key constraint on each published table.Replication uses the distribution databases hosted on a distributor to centrally manage and control the configuration and operation of data replication.While the actual data to be replicated are within user databases, SQL Server replication uses objects and artifacts outside the user databases, such as master database, msdb database, distribution databases, and even file systems.Because a replicated database cannot be detached,replication had to be removed from these databases first.Beginning with SQL Server 2005, you can move or rename files without detaching and re-attaching the database, with no effect onreplication.Many enterprise customers have asked the capability to combine the usage of SQL Server replication and Always On, such that they can place replication distribution databases within an Always On AG to achieve high availability for their distribution databases, with the expectation that after doing so and when AG failover happens, SQL Server replication will continue functioning seamlessly and correctly.While the Replication publication and subscription databases can be configured to use Availability Groups, this support was lacking for the replication Distribution Databases.
Merge replication adds the column rowguid to every table, unless the table already has a column of data type uniqueidentifier with the ROWGUIDCOL property set (in which case this column is used).A: SQL Server supports a wide variety of schema changes on published objects, including adding and dropping columns. DROP COLUMN at the Publisher, and the statement is replicated to Subscribers and then executed to drop the column.Subscribers running versions of SQL Server prior to SQL Server 2005 support adding and dropping columns through the stored procedures sp_repladdcolumn and sp_repldropcolumn A: Use validation.Merge replication does not require a primary key, but if one is present, it must be replicated.Snapshot replication does not require a primary key. There are no restrictions on the number or types of publications that can use the same distribution database.