INSERT OR UPDATE only inserts

I am trying to do a INSERT OR UPDATE SQL query, but the query always inserts new rows to table. Is it how I defined the table or am I mising something in the query?

table defines as,

Class AH.AHCOMMON.Tables.HospDepartmentData Extends %Persistent [ Language = objectscript ]
{

Property Tablespace As %Library.String(MAXLEN = 50) [ SqlColumnNumber = 2 ];

Property DepartmentId As %Library.String(MAXLEN = 50) [ SqlColumnNumber = 3 ];

Property TimezoneName As %Library.String(MAXLEN = 100) [ SqlColumnNumber = 4 ];

Property PatientDepartmentName As %Library.String(MAXLEN = 100) [ SqlColumnNumber = 5 ];

Property Status As %Library.String(MAXLEN = 50) [ SqlColumnNumber = 6 ];

Property CreatedDateTime As %DateTime [ SqlColumnNumber = 7, SqlComputeCode = {set {CreatedDateTime}=$ZDT($H,3)}, SqlComputed, SqlComputeOnChange = %%INSERT ];

Property UpdatedDateTime As %DateTime [ SqlColumnNumber = 8, SqlComputeCode = {set {UpdatedDateTime}=$ZDT($H,3)}, SqlComputed, SqlComputeOnChange = (%%INSERT, %%UPDATE) ];