-- modify "anwesenheit" table
ALTER TABLE "anwesenheit" ALTER COLUMN "timestamp" SET NOT NULL, ALTER COLUMN "geraet_id" SET NOT NULL, ALTER COLUMN "anwesenheit_typ" SET NOT NULL;
-- modify "s_personal_daten" table
ALTER TABLE "s_personal_daten" ALTER COLUMN "vorname" SET NOT NULL, ALTER COLUMN "nachname" SET NOT NULL, ALTER COLUMN "arbeitszeit_per_tag" SET NOT NULL, ALTER COLUMN "vorgesetzter_pers_nr" SET NOT NULL, ALTER COLUMN "arbeitszeit_per_woche" SET NOT NULL;