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hrColumnCannotIndex
Diagnostic focus
hrColumnCannotIndex means the selected long-value or otherwise unsupported column cannot participate in an index key.
This is the legacy Directory Service backup/restore HRESULT form of JET_errColumnCannotIndex (0xC80005E9).
The key comparison is: hrIndexInvalidDef is general; this code identifies the column capability that makes indexing impossible. The first useful observation is to record column type, maximum length, multivalue/tagged flags, and intended key segment. This evidence separates schema definition, row-size accounting, null semantics, multivalue selection, and stale column IDs.
The ESE objects in play
| Diagnostic layer | column schema, row-size accounting, tagged/multivalued storage, and column identifiers |
|---|---|
| Typical API surface | JetAddColumn, JetDeleteColumn, JetSetColumn, JetRetrieveColumn, and JET_COLUMNDEF |
| Code-specific condition | the selected long-value or otherwise unsupported column cannot participate in an index key |
| First corrective direction | index a bounded surrogate or normalized searchable field instead of the long payload |
Fixed, variable, tagged, and long-value columns consume row space differently. Column IDs are metadata scoped to a table and should be refreshed after schema changes.
Evidence that resolves the ambiguity
- Code-specific observation: record column type, maximum length, multivalue/tagged flags, and intended key segment.
- the complete row-size contribution from fixed, variable, tagged, and long-value data; associate it with this result rather than with a later generic exception.
- JET_COLUMNDEF fields, flags, code page, maximum length, and column ID origin; associate it with this result rather than with a later generic exception.
- the encoded value length, null/empty state, and itag sequence.
Nearby results that mean something different
hrColumn2ndSysMaint | the table is being given a second engine-maintained autoincrement or version column |
|---|---|
hrColumnDoesNotFit | the field update cannot fit in the current record layout and remaining row budget |
hrCannotBeTagged | an autoincrement or version column was defined with tagged or multivalued semantics |
A disciplined correction path
- Freeze the failing request context and record
0xC80005E9, the Jet API name, and the current instance/session ownership. - Verify the code-specific precondition: record column type, maximum length, multivalue/tagged flags, and intended key segment.
- Apply the targeted fix: index a bounded surrogate or normalized searchable field instead of the long payload.
- Before retrying the operation, reconcile column metadata, row layout, and the exact stored value state.
Actions that can hide or worsen the problem
- Do not alter the column schema in place without a migration and rollback plan.
- Do not collapse null, zero-length data, missing value, and tagged-value deletion into one state.
Technical references
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