А что у тебя за сервер баз данных?

Приведи код, которым пытаешься удалить записи...

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TCustomADODataSet.DeleteRecords

Deletes one or more records in the dataset.

TAffectRecords = (arCurrent, arFiltered, arAll, arAllChapters);
procedure DeleteRecords(AffectRecords: TAffectRecords = arAll);

Description

Use DeleteRecords to delete one or more records from the recordset the ADO dataset component represents.

If the recordset does not support record deletions, an exception is raised. Use the Supports method to determine whether the recordset supports deleting records.

If the dataset was opened in batch update mode, the records are only marked for deletion. Apply the batch deletions by calling the UpdateBatch method. If the dataset is not in batch update mode, the records are immediately removed from the base table.

AffectRecords is a TAffectRecords constant that determines which records are deleted by DeleteRecords. The default value for the AffectRecords parameter is arAll, which causes all records in the recordset to be deleted.

Option Meaning

arCurrent Only the deletes the current record.
arFiltered Only deletes records accessible through the current filter.
arAll Deletes all records in the recordset.
arAllChapters Deletes records in all chapters (ADO chapters)

Прямо так и говорит, без указания причины?
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