I'm trying to perform an INSERT operation with an ON CONFLICT DO UPDATE clause in PostgreSQL. My table contains column names with aliases (e.g., "ITEM_CODE(material_code)"), and I want to update the corresponding fields when a conflict occurs on "ITEM_CODE(material_code)". Here's the SQL query I'm using:

INSERT INTO api_itemmaster (
    "ITEM_CODE(material_code)",
    "ITEM_NAME(material_name)",
    "ITEM_GROUP_CODE",
    "UNIT(base_unit)",
    "PACK(pack_size)",
    "ITEM_CLASS_CODE(material_type)",
    "DIVISION_CODE(division)",
    "SEGMENT_CODE",
    "CAT_CODE",
    "ACTIVE",
    "FORMT",
    created_on,
    updated_on,
    active_state
) VALUES (
    '5000',
    'OSKAR',
    '225',
    'STR',
    '15',
    'ZF',
    '8000',
    '30000',
    '004',
    '1',
    '20',
    CURRENT_TIMESTAMP,
    CURRENT_TIMESTAMP,
    false
) ON CONFLICT ("ITEM_CODE(material_code)") 
DO UPDATE SET
    "ITEM_NAME(material_name)" = EXCLUDED."ITEM_NAME(material_name)",
    "ITEM_GROUP_CODE" = EXCLUDED."ITEM_GROUP_CODE",
    "UNIT(base_unit)" = EXCLUDED."UNIT(base_unit)",
    "PACK(pack_size)" = EXCLUDED."PACK(pack_size)",
    "ITEM_CLASS_CODE(material_type)" = EXCLUDED."ITEM_CLASS_CODE(material_type)",
    "DIVISION_CODE(division)" = EXCLUDED."DIVISION_CODE(division)",
    "SEGMENT_CODE" = EXCLUDED."SEGMENT_CODE",
    "CAT_CODE" = EXCLUDED."CAT_CODE",
    "ACTIVE" = EXCLUDED."ACTIVE",
    "FORMT" = EXCLUDED."FORMT",
    updated_on = EXCLUDED.updated_on;

However, the ON CONFLICT DO UPDATE clause doesn't seem to work, and no updates are applied to the existing row.

Ensured that the table and column names are correct. Verified that the ITEM_CODE(material_code) constraint is unique in the table. Confirmed that the syntax aligns with PostgreSQL's ON CONFLICT documentation.