When you create a field with the serial type, PostgreSQL server automatically creates a sequence, and values from this sequence will be used as default for this field
To fill Id field automatically you can use two ways:
1) Set
aqrParts.Options.DefaultValues := True.
In this case default value for the Id field will be set to "nextval(''parts.spareparts_seq''::regclass)" and the Id field will be filled automatically.
2) Set
aqrParts.SpecificOptions.Values['KeySequence'] := 'spareparts_seq';
aqrParts.SpecificOptions.Values['SequenceMode'] := 'smInsert';
In this case field Id will be filled from this sequence.