-20181   COLUMN CANNOT BE ADDED TO INDEX index-name

An attempt was made to add a column to an index, but the column could not be added.

index-name

The name of the index.

The column could not be added because of limitations on the clause specified for the ALTER INDEX statement:

ALTER INDEX ADD COLUMN

The column cannot be added for any of a variety of reasons, including those shown below:

• The index is an auxiliary index.
• The index enforces uniqueness of values for a ROWID column.
• The index is a partitioning index, and index-based partitioning is being used.
• The index is an XML index.
• The index is an extended index.
• The index is defined with a period with the WITHOUT OVERLAPS clause.
• The index has at least one INCLUDE column.
• The index enforces a primary key, unique key, or referential constraint, or it matches a foreign key.

ALTER INDEX ADD INCLUDE

The column cannot be added for any of a variety of reasons, including those shown below:

• The index is an auxiliary index.
• The index is a non-unique index.
• The index is a partitioning index, and index-based partitioning is being used.
• The index is an XML index.
• The index is an extended index (such as an expression-based index).
• The index is defined with a period with the WITHOUT OVERLAPS clause.
• The index matches a foreign key.