Vertica Blog

Vertica Blog

Flattened Tables

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Define a Vertica Flattened Table Column as Having Both DEFAULT and SET USING Constraints

James Knicely, Vertica Field Chief Technologist
January 31, 2020

Columns in a flattened table can query other tables with constraints DEFAULT and SET USING . Vertica executes DEFAULT queries only on new rows when they are added to the flattened table, through load operations such as INSERT and COPY. Thereafter, changes in the original data sources have no effect on the flattened table. Vertica...

Vertica Quick Tip: Which Column in my Flattened Table caused the “Subquery used as an expression returned more than one row” Error?

Soniya Shah, Information Developer
May 29, 2018

This blog post was authored by Jim Knicely. A flattened table contains columns that are derived from query-expressions that must return only one row and column value, or none. If a column’s query-expression does return more than one row you will get a “Subquery used as an expression returned more than one row” error. If...