merge-restrictions_snip.md

Constraint enforcement

If primary key, unique key, or check constraints are enabled for automatic enforcement in the target table, Vertica enforces those constraints when you load new data. If a violation occurs, Vertica rolls back the operation and returns an error.

Columns prohibited from merge

The following columns cannot be specified in a merge operation; attempts to do so return with an error:

  • IDENTITY columns, or columns whose default value is set to a named sequence.

  • Vmap columns such as __raw__ in flex tables.

  • Columns of complex types ARRAY, SET, or ROW.