Can you recompile a view?

You may want to recompile a view explicitly after altering one of its base tables to ensure that the alteration does not affect the view or other objects that depend on it. You can also use ALTER VIEW to define, modify, or drop view constraints. This statement does not change the definition of an existing view.

Table of Contents

How do you refresh a view in Oracle?

Query Rewrite Method 1: Text Match Rewrite.
Query Rewrite Method 2: Join Back.
Query Rewrite Method 3: Aggregate Computability.
Query Rewrite Method 4: Aggregate Rollup.
Query Rewrite Method 5: Rollup Using a Dimension.
Query Rewrite Method 6: When Materialized Views Have Only a Subset of Data.

How we can refresh materialized view?

To update the data in a materialized view, you can use the REFRESH MATERIALIZED VIEW statement at any time. When you use this statement, Amazon Redshift identifies changes that have taken place in the base table or tables, and then applies those changes to the materialized view.

How can you tell when a materialized view was last refreshed?

Question

SELECT.
OWNER,
MVIEW_NAME,
to_char(last_refresh_date, ‘yyyymmddhh24miss’) LAST_REFRESH_DATE.
FROM all_mviews.
WHERE owner = ‘MY_OWNER_NAME’
AND mview_name = ‘MY_MATERIALIZED_VIEW_NAME’

What is force Editionable view?

FORCE and EDITIONABLE are two different things. FORCE instructs the database to create the view regardless of whether the query is valid. Default behaviour is for a CREATE VIEW statement to fail if its query does not compile for any reason (e.g. invalid syntax, missing privileges on a referenced object).

What is forced view in Oracle?

Force View does forces the creation of a View even when the View will be invalid. NoForce Is the default. Code. CREATE FORCE VIEW.

What is the difference between materialized view and view?

Views are generally used when data is to be accessed infrequently and data in table get updated on frequent basis. On other hand Materialized Views are used when data is to be accessed frequently and data in table not get updated on frequent basis.

Can we update materialized view in Oracle?

Primary key materialized views that contain a selected class of subqueries can still be incrementally (or fast) refreshed, if each master referenced has a materialized view log. A fast refresh uses materialized view logs to update only the rows that have changed since the last refresh.

Why materialized view is faster than view?

Materialized views are faster than tables because of their “cache” (i.e. the query results for the view); in addition, if data has changed, they can use their “cache” for data that hasn’t changed and use the base table for any data that has changed.

Do we need to refresh materialized view?

Unlike indexes, materialized views are not automatically updated with every data change. They must explicitly be refreshed, either on every commit, on a periodically time schedule or – typically in data warehouses – at the end of an ETL job.

What is force refresh in materialized view?

A fast refresh requires having a materialized view log on the source tables that keeps track of all changes since the last refresh, so any new refresh only has changed (updated, new, deleted) data applied to the MV. A complete refresh does what it says: it completely refreshes all data in the MV.

How long did Oracle materialized view refresh run?

The “Complete” refresh (7.75 mins) is more faster than the “Fast” refresh (48.9 mins), The parameter “atomic_refresh=FALSE” works only with “complete” refresh, so “truncate” is only possible with “complete“.

What is Editioned view?

An editioning view is a single-table view that selects all rows from the base table and displays a subset of the base table columns. You can use an editioning view to isolate an application from DDL changes to the base table during administrative operations such as upgrades.

What is difference between normal view and materialized view?

Can a view be updated?

Yes we can insert,Update and delete, if a view is not complex. In SQL, a view is a virtual table based on the result-set of an SQL statement.

Can a view be updated in Oracle?

Answer: A VIEW in Oracle is created by joining one or more tables. When you update record(s) in a VIEW, it updates the records in the underlying tables that make up the View. So, yes, you can update the data in an Oracle VIEW providing you have the proper privileges to the underlying Oracle tables.

Why use materialized view instead of a table?

Materialized views are basically used to increase query performance since it contains results of a query. They should be used for reporting instead of a table for a faster execution.

Which is better view or materialized view?

The performance of Materialized view it is better than normal View because the data of materialized view will be stored in table and table may be indexed so faster for joining also joining is done at the time of materialized views refresh time so no need to every time fire join statement as in case of view.

When should a view be refreshed?

Views need to be refreshed if the underlying tables change at all. That can change the datatypes of the view’s columns or rearrange its indexes. Therefore, it needs to know.

Do materialized views automatically refresh?

How do I speed up a materialized view refresh?

– Use super-fast solid-state disks – The easiest and most reliable way is to speed-up a materialized view refresh is to move the target tables and MV’s to SSD. SSD runs several hundred times faster than platter disk, and it plops right in, just a few hours to install.

What is an Editionable view?

EDITIONABLE is a keyword relating to Edition-based Redefinition. This is a mechanism Oracle provides which allows us to support multiple versions of the same object in our database. This can be very useful for wrangling complex deployments in live environments.

Does view automatically update?

Yes, they are updated, every time you use them.

Can we do DML on views?

A view can be defined as a virtual table or a stored query and the data accessible through a view is not stored in the database as a distinct object. Only the select statement is stored on the database instead. However, views can be used and perform DML operations ( Insert , Update & Delete ) also.

Are views updatable?

Yes, they are updatable but not always. Views can be updated under followings: If the view consists of the primary key of the table based on which the view has been created.

Can you recompile a view?