Informix Error -548

Reasons / Common Causes

-548 fires when CREATE TRIGGER or a referential (FOREIGN KEY) constraint definition targets a temporary table — another entry in the same family of temp-table restrictions as -508/-509/-510/ -532, since a session-scoped table isn't meant to carry these kinds of persistent, cross-session relationships.

1. CREATE TRIGGER issued against a temp table, per the official guidance — a trigger implies ongoing behavior tied to a table that outlives the session, which a temp table doesn't.
2. A FOREIGN KEY constraint defined on (or referencing) a temp table, per the official guidance's general framing of referential constraints not being supported on temp tables.
3. Staging/ETL code that builds a temp table and then tries to attach the same validation logic (triggers, foreign keys) used on the permanent table it's staging data for, without realizing temp tables can't carry that logic directly.

Solutions / Resolution

1. Create the table as a permanent table instead, per the official guidance, if a trigger or referential constraint is genuinely needed on it:

   CREATE TABLE staging_orders (order_id INT, customer_id INT REFERENCES customers(customer_id));
   

   then create the trigger on it as usual.
2. If the table genuinely needs to be temporary, enforce the equivalent logic in application code instead — validate referenced values before inserting into the temp table, since the database won't enforce it there.
3. Drop the temp table once its session-scoped purpose is done, per the normal temp-table lifecycle, rather than trying to give it permanent-table capabilities.

Examples

The disallowed attempt

CREATE TEMP TABLE staging_orders (order_id INT, customer_id INT);
CREATE TRIGGER trg_staging_orders INSERT ON staging_orders
  REFERENCING NEW AS post FOR EACH ROW (EXECUTE PROCEDURE validate_order(post.order_id));
-- -548: staging_orders is a temporary table

Making the table permanent instead

CREATE TABLE staging_orders (order_id INT, customer_id INT REFERENCES customers(customer_id));
CREATE TRIGGER trg_staging_orders INSERT ON staging_orders
  REFERENCING NEW AS post FOR EACH ROW (EXECUTE PROCEDURE validate_order(post.order_id));

Diagnostic Checks

1. Confirm whether the table is temporary before attempting CREATE TRIGGER or a referential constraint against it — if so, per the official guidance, making it permanent is the documented path forward.

Related Errors / Related Topics

• -508 — "Cannot rename a temporary table." Same family of temp-table restrictions.
• -509 — "Cannot rename a column in a temporary table." Same family.
• -510 — "Cannot create synonym for temporary table table-name." Same family.
• -532 — "Cannot alter temporary table table-name." Same family.

Part of the standing family of temp-table restrictions — make the table permanent if triggers or referential constraints are genuinely needed.