A snapshot is a read-only copy of a master table located on a remote node. Snapshots can be queried but not updated; only the master table can be updated. Snapshots are periodically refreshed to reflect changes made to the master table.
A snapshot is a read-only copy of a master table / output of a query
based on multiple tables located on a remote location.Once these are read only so can not have DML statments. Yes they can be refeshed periodically based the condition defined while creating the snapshot. Advance version of snapshot is materialized views.
Database snapshot is a read-only view of a database. It is taken from the source database and resides on the same server as the database. A snapshot uses a sparse file to store original pages from the source database. A sparse file is empty when a snapshot is taken. Whenever a page is changed in the source database the Database Engine copies the original page to the sparse file in the snapshot before updating the page in the source database. The same process is repeated whenever a page of the source database is changed. The snapshot is used to recover data by reapplying the pages from the snapshot to the source database. Database snapshot is not available if its source database is disconnected for any reason.
