Query rewrites are particularly useful in a data warehouse environment.
A materialized view log is a schema object that records changes to a master table's data so that a materialized view defined on the master table can be refreshed incrementally.
Problem: You can't update records in multiple tables when the view references more than one base table.
Using materialized views against remote tables is the simplest way to achieve replication of data between sites.
The example code in this article assumes DB1 is the master instance and DB2 is the materialized view site.
A synonym is an alias for any table, view, materialized view, sequence, procedure, function, or package.
A public synonym is owned by the user group PUBLIC and every user in a database can access it.
A materialized view can be stored in the same database as its base table(s) or in a different database.
Materialized views stored in the same database as their base tables can improve query performance through query rewrites.
Materialized views are schema objects that can be used to summarize, precompute, replicate, and distribute data. Unlike an ordinary view, which does not take up any storage space or contain any data.
The existence of a materialized view is transparent to SQL, but when used for query rewrites will improve the performance of SQL execution.
You can only update columns that belong to a single base table.