What is Rowid materialized view?
A ROWID materialized view is based on the physical row identifiers (rowids) of the rows in a master. ROWID materialized views can be used for materialized views based on master tables that do not have a primary key, or for materialized views that do not include all primary key columns of the master tables.
What is the difference between object and Rowid materialized view?
2) Another difference between View vs materialized view is that, when we create a view using any table, rowid of view is the same as the original table but in the case of Materialized view rowid is different.
Can we create view on materialized view?
Use the CREATE MATERIALIZED VIEW statement to create a materialized view. A materialized view is a database object that contains the results of a query. The FROM clause of the query can name tables, views, and other materialized views.
How do I create a materialized view log in a table?
CREATE MATERIALIZED VIEW LOG
- Use the CREATE MATERIALIZED VIEW LOG statement to create a materialized view log, which is a table associated with the master table of a materialized view.
- create_materialized_vw_log::=
- logging_clause::=
- new_values_clause::=
- schema.
- table.
Does a materialized view need a primary key?
Primary key materialized views allow materialized view master tables to be reorganized without affecting the eligibility of the materialized view for fast refresh. The master table must contain an enabled primary key constraint. You cannot specify this clause for an object materialized view.
Can you create or replace materialized view?
No, you cannot alter the query of a materialized view without dropping it. The CREATE MATERIALIZED VIEW syntax does not support that feature. The ALTER MATERIALIZED VIEW is used to modify an existing materialized view in one or more of the following ways: To change its storage characteristics.
What’s the purpose of a materialized view log?
A materialized view log can capture the primary keys, row IDs, or object identifiers of rows that have been updated in the master table.
Can I create a materialized view log with rowid?
Another key aspect to note is that your materialized view logs must be created as with rowid.
How do I create a materialized view from an existing table?
To create a materialized view that is based on an existing table, use the ON PREBUILT TABLE clause. The column_properties clause lets you specify the storage characteristics of a LOB, nested table, varray, or XMLType column. The object_type_col_properties are not relevant for a materialized view.
Where are data rows stored in a materialized view?
In such a materialized view, data rows are stored in an index defined on the primary key of the materialized view. You can specify index organization for the following types of materialized views: Read-only and updatable object materialized views. You must ensure that the master table has a primary key.
How to enable query rewrite on a materialized view?
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. You cannot define a materialized view with a subquery in the select list of the defining query.