Which three options are true about MVIEWs?

Question

Options

• AThe defining query of an MVIEWs may be based on a populated table.
• BQueries that are rewritten to an MVIEW will never obtain results from the result cache.
• CAll MVIEWS may be configured to support "refresh on demand".
• DThe defining query of an MVIEW may be based on non_partitioned table.
• EAll MVIEWs may be configured to support "refresh on commit"

• A
  81% (30)
• D
  14% (5)
• E
  5% (2)

Explanation

A: The defining query of a materialized view can select from tables, views, or materialized views owned by the user SYS, but you cannot enable QUERY REWRITE on such a materialized view. B: You cannot specify the following CREATE MATERIALIZED VIEW clauses: CACHE or NOCACHE, CLUSTER, or ON PREBUILT TABLE. C: Specify ON DEMAND to indicate that the materialized view will be refreshed on demand by calling one of the three DBMS_MVIEW refresh procedures. If you omit both ON COMMIT and ON DEMAND, ON DEMAND is the default. E: Materialized views can only refresh ON COMMIT in certain situations. The materialized view cannot contain object types or Oracle-supplied types. The base tables will never have any distributed transactions applied to them. * Oracle uses materialized views (also known as snapshots in prior releases) to replicate data to non- master sites in a replication environment and to cache expensive queries in a data warehouse environment. * A materialized view is a replica of a target master from a single point in time. The master can be either a master table at a master site or a master materialized view at a materialized view site. Whereas in multimaster replication tables are continuously updated by other master sites, materialized views are updated from one or more masters through individual batch updates, known as a refreshes, from a single master site or master materialized view site.

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