Virtual Columns
Virtual columns are defined by evaluating an expression the results of which become the metadata of the columns for tables. Virtual columns can be defined at table creation or modification time.
Virtual columns enable application developers to define computations and transformations as the column (metadata) definition of tables without space consumption. This makes application development easier and less error-prone, as well as enhances query optimization by providing additional statistics to the optimizer for these virtual columns.
CREATE TABLE GC.VIRTUAL_COL
(NO NUMBER,
NAME VARCHAR2(10),
NO_NAME AS (NO||NAME)
)
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