Cannot add or change records
In this scenario, as James Anderson suggests, one-to-one relationships are not the way to do it. One patient may be checked up, operated on, discharged etc., more than once. The tables you have now should be renamed as follows and given their own unique ID primary keys to better represent what they are trying to model:


PatientRegular to Regular
PatientDischarge to Discharge
PatientOperate to Operation
PatientCheckup to Checkup


They should still retain their PatientID columns but those columns should become foreign key reference columns back to the PatientID column in the Patient table. In other words, you will have one-to-many relationships between:


Patient to Regular
Patient to Discharge
Patient to Operation
Patient to Checkup