I'm trying to write a table trigger which queries another table that is outside the schema where the trigger will reside. Is this possible? It seems like I have no problem querying tables in my schema but I get:
Error: ORA-00942: table or view does not exist
when trying trying to query tables outside my schema.
EDIT
My apologies for not providing as much information as possible the first time around. I was under the impression this question was more simple.
I'm trying create a trigger on a table that changes some fields on a newly inserted row based on the existence of some data that may or may not be in a table that is in another schema.
The user account that I'm using to create the trigger does have the permissions to run the queries independently. In fact, I've had my trigger print the query I'm trying to run and was able to run it on it's own successfully.
I should also note that I'm building the query dynamically by using the EXECUTE IMMEDIATE statement. Here's an example:
CREATE OR REPLACE TRIGGER MAIN_SCHEMA.EVENTS
BEFORE INSERT
ON MAIN_SCHEMA.EVENTS REFERENCING OLD AS OLD NEW AS NEW
FOR EACH ROW
DECLARE
rtn_count NUMBER := 0;
table_name VARCHAR2(17) := :NEW.SOME_FIELD;
key_field VARCHAR2(20) := :NEW.ANOTHER_FIELD;
BEGIN
CASE
WHEN (key_field = 'condition_a') THEN
EXECUTE IMMEDIATE 'select count(*) from OTHER_SCHEMA_A.'||table_name||' where KEY_FIELD='''||key_field||'''' INTO rtn_count;
WHEN (key_field = 'condition_b') THEN
EXECUTE IMMEDIATE 'select count(*) from OTHER_SCHEMA_B.'||table_name||' where KEY_FIELD='''||key_field||'''' INTO rtn_count;
WHEN (key_field = 'condition_c') THEN
EXECUTE IMMEDIATE 'select count(*) from OTHER_SCHEMA_C.'||table_name||' where KEY_FIELD='''||key_field||'''' INTO rtn_count;
END CASE;
IF (rtn_count > 0) THEN
-- change some fields that are to be inserted
END IF;
END;
The trigger seams to fail on the EXECUTE IMMEDIATE with the previously mentioned error.
EDIT
I have done some more research and I can offer more clarification.
The user account I'm using to create this trigger is not MAIN_SCHEMA or any one of the OTHER_SCHEMA_Xs. The account I'm using (ME) is given privileges to the involved tables via the schema users themselves. For example (USER_TAB_PRIVS):
GRANTOR GRANTEE TABLE_SCHEMA TABLE_NAME PRIVILEGE GRANTABLE HIERARCHY
MAIN_SCHEMA ME MAIN_SCHEMA EVENTS DELETE NO NO
MAIN_SCHEMA ME MAIN_SCHEMA EVENTS INSERT NO NO
MAIN_SCHEMA ME MAIN_SCHEMA EVENTS SELECT NO NO
MAIN_SCHEMA ME MAIN_SCHEMA EVENTS UPDATE NO NO
OTHER_SCHEMA_X ME OTHER_SCHEMA_X TARGET_TBL SELECT NO NO
And I have the following system privileges (USER_SYS_PRIVS):
USERNAME PRIVILEGE ADMIN_OPTION
ME ALTER ANY TRIGGER NO
ME CREATE ANY TRIGGER NO
ME UNLIMITED TABLESPACE NO
And this is what I found in the Oracle documentation:
To create a trigger in another user's
schema, or to reference a table in
another schema from a trigger in your
schema, you must have the CREATE ANY
TRIGGER system privilege. With this
privilege, the trigger can be created
in any schema and can be associated
with any user's table. In addition,
the user creating the trigger must
also have EXECUTE privilege on the
referenced procedures, functions, or
packages.
Here: Oracle Doc
So it looks to me like this should work, but I'm not sure about the "EXECUTE privilege" it's referring to in the doc.
