Versions

The database server binds the snapshot version when a transaction is created, after the transaction has obtained the necessary write locks on the table or the table row. Table-level versioning enables single-writer access and table-level locking. Row-level versioning (RLV) enables concurrent writer access and row-level locking for RLV-enabled tables.

• Table-Level Snapshot Versioning
  The default transaction processing behavior, table-level snapshot versioning, allows multiple writers to modify a table serially—that is, one after the other, never more than one at a time—while multiple readers continue to work on an original copy of the table.
• Row-Level Snapshot Versioning
  Row-level snapshot versioning applies only to tables enabled for in-memory RLV storage. Row-level snapshot versioning allows multiple writers to make concurrent DML changes to a table, but never to the same rows at the same time.
• Viewing the Versioning Type of a Transaction
  Use the sp_iqtransaction stored procedure to view the versioning type (either table-level or row-level) of each active transaction.
• Temporary Table Versioning
  A temporary table that is created in the database is called a global temporary table. A temporary table that is declared (rather than created in the database) is called a local temporary table.