|ORA-01404:||ALTER COLUMN will make an index too large|
|Cause:||Increasing the length of a column would cause the combined length of the columns specified in a previous CREATE INDEX statement to exceed the maximum index length (255). The total index length is computed as the sum of the width of all indexed columns plus the number of indexed columns. Date fields are calculated as a length of 7, character fields are calculated at their defined width, and numeric fields are length 22.|
|Action:||The only way to alter the column is to drop the affected index. The index cannot be re-created if to do so would exceed the maximum index width.