Setting 'Valid to date' on Portal item using SQL script?

Every year at fiscal year-end, we temporarily block the entry of Expense Reports, Travel Authorizations, and Cash Advances. To do this, we set a ‘Valid to date’ in the past for the relevant pages under Portal > Structure and Content. I’m attempting to automate this process with a SQL script. Below is my initial attempt, but it didn’t update the ‘Valid to date’ field as expected. I observed numerous deletes and inserts during a trace. Before considering other options, could anyone share a working script or suggest an alternative method?

UPDATE PSPRSMDEFN SET PORTAL_EXPIRE_DT = TO_DATE('2024-01-01','YYYY-MM-DD')