Example:
dbadmin=> CREATE TABLE test1 (c INT);
CREATE TABLE
dbadmin=> INSERT INTO test1 SELECT 1;
OUTPUT
--------
1
(1 row)
dbadmin=> SELECT projection_name, create_type FROM projections WHERE anchor_table_name = 'test1';
projection_name | create_type
-----------------+------------------
test1_super | DELAYED CREATION
(1 row)
dbadmin=> DROP TABLE test1;
DROP TABLE
A projection with a create type of “DELAYED CREATION” is an auto-projection. Auto-projections are superprojections that Vertica automatically generates for tables.If you create a projection manually or via the Database Designer (non-auto projections), you will need to drop the table specifying the CASCADE option.
dbadmin=> CREATE PROJECTION test1_pr AS SELECT c FROM test1 ORDER BY c UNSEGMENTED ALL NODES;
CREATE PROJECTION
dbadmin=> SELECT projection_name, create_type FROM projections WHERE anchor_table_name = 'test1';
projection_name | create_type
-----------------+-------------------
test1_pr | CREATE PROJECTION
(1 row)
dbadmin=> DROP TABLE test1;
NOTICE 4927: The Projection test1_pr depends on Table test1
ROLLBACK 3128: DROP failed due to dependencies
DETAIL: Cannot drop Table test1 because other objects depend on it
HINT: Use DROP ... CASCADE to drop the dependent objects too
dbadmin=> DROP TABLE test1 CASCADE;
DROP TABLE
Helpful Links:https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/Statements/DROPTABLE.htm
https://www.vertica.com/docs/latest/HTML/Content/Authoring/AdministratorsGuide/Projections/AutoProjections.htm
Have fun!
About the Author
James Knicely
Vertica Field Chief Technologist
I've had the privilege of working with many database technologies in my career. But after being introduced to Vertica in May of 2011 as a client, I was hooked on the new technology after witnessing a query run in milliseconds that had previously ran for hours on the legacy database we had in place. It was then that I knew I wanted to eventually join the Vertica team, and 4 years later I did! I am currently a Vertica evangelist and am ready to help you get on board! Please feel free to reach out to me with any questions you have about Vertica and make sure to follow my Vertica Quick Tips!
