Обсуждение: Doubt On JSON in Postgresql
Dears,
I have written the below trigger function used for recording changes to tables into an audit log table.It will record the old and new records, the table affected, the user who made the change, and a timestamp for each change in JSON format.
Right now the issue is my business user needs only the particular column which have changed from old to new not the whole json record.
i.e i need a select query to find the difference between two json columns( v_old_data and v_new_data ).
Please give me the solution.
Thanks,
Selva
+601136296272
CREATE OR REPLACE FUNCTION audit.if_modified_func() RETURNS TRIGGER AS $body$ DECLARE v_old_data json; v_new_data json; BEGIN /* If this actually for real auditing (where you need to log EVERY action), then you would need to use something like dblink or plperl that could log outside the transaction, regardless of whether the transaction committed or rolled back. */ /* This dance with casting the NEW and OLD values to a ROW is not necessary in pg 9.0+ */ IF (TG_OP = 'UPDATE') THEN v_old_data := ROW_TO_JSON(OLD.*); v_new_data := ROW_TO_JSON(NEW.*); INSERT INTO audit.logged_actions (schema_name,table_name,user_name,action,original_data,new_data,query) VALUES (TG_TABLE_SCHEMA::TEXT,TG_TABLE_NAME::TEXT,session_user::TEXT,substring(TG_OP,1,1),v_old_data,v_new_data); RETURN NEW; ELSIF (TG_OP = 'DELETE') THEN v_old_data := ROW_TO_JSON(OLD.*); INSERT INTO audit.logged_actions (schema_name,table_name,user_name,action,original_data,query) VALUES (TG_TABLE_SCHEMA::TEXT,TG_TABLE_NAME::TEXT,session_user::TEXT,substring(TG_OP,1,1),v_old_data); RETURN OLD; ELSIF (TG_OP = 'INSERT') THEN v_new_data := ROW_TO_JSON(NEW.*); INSERT INTO audit.logged_actions (schema_name,table_name,user_name,action,new_data,query) VALUES (TG_TABLE_SCHEMA::TEXT,TG_TABLE_NAME::TEXT,session_user::TEXT,substring(TG_OP,1,1),v_new_data); RETURN NEW; ELSE RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - Other action occurred: %, at %',TG_OP,now(); RETURN NULL; END IF; EXCEPTION WHEN data_exception THEN RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - UDF ERROR [DATA EXCEPTION] - SQLSTATE: %, SQLERRM: %',SQLSTATE,SQLERRM; RETURN NULL; WHEN unique_violation THEN RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - UDF ERROR [UNIQUE] - SQLSTATE: %, SQLERRM: %',SQLSTATE,SQLERRM; RETURN NULL; WHEN OTHERS THEN RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - UDF ERROR [OTHER] - SQLSTATE: %, SQLERRM: %',SQLSTATE,SQLERRM; RETURN NULL; END; $body$ LANGUAGE plpgsql
CREATE TRIGGER t_if_modified_trg AFTER INSERT OR UPDATE OR DELETE ON temp_tblFOR EACH ROW EXECUTE PROCEDURE audit.if_modified_func();
I've done something similar, but I only put into the JSON those fields which changed, using IS DISTINCT FROM... -- Scott Ribe scott_ribe@elevated-dev.com https://www.linkedin.com/in/scottribe/ > On Jan 7, 2019, at 10:22 PM, selva kumaran <amselvakumaran@gmail.com> wrote: > > Dears, > > I have written the below trigger function used for recording changes to tables into an audit log table.It will record theold and new records, the table affected, the user who made the change, and a timestamp for each change in JSON format. > > Right now the issue is my business user needs only the particular column which have changed from old to new not the wholejson record. > i.e i need a select query to find the difference between two json columns( v_old_data and v_new_data ). > > Please give me the solution. > Thanks, > Selva > +601136296272 > > > > > > CREATE OR REPLACE FUNCTION audit.if_modified_func() RETURNS TRIGGER AS > $body$ > > DECLARE > > v_old_data json > ; > > v_new_data json > ; > BEGIN > > > /* If this actually for real auditing (where you need to log EVERY action), > then you would need to use something like dblink or plperl that could log outside the transaction, > regardless of whether the transaction committed or rolled back. > */ > > > > /* This dance with casting the NEW and OLD values to a ROW is not necessary in pg 9.0+ */ > > > > IF (TG_OP = 'UPDATE') THEN > > v_old_data > := ROW_TO_JSON(OLD.*); > > v_new_data > := ROW_TO_JSON(NEW.*); > > > INSERT INTO audit.logged_actions (schema_name,table_name,user_name,action,original_data,new_data,query) > > > VALUES (TG_TABLE_SCHEMA::TEXT,TG_TABLE_NAME::TEXT,session_user::TEXT,substring(TG_OP,1,1),v_old_data,v_new_data); > > > RETURN NEW; > > > ELSIF (TG_OP = 'DELETE') THEN > > v_old_data > := ROW_TO_JSON(OLD.*); > > > INSERT INTO audit.logged_actions (schema_name,table_name,user_name,action,original_data,query) > > > VALUES (TG_TABLE_SCHEMA::TEXT,TG_TABLE_NAME::TEXT,session_user::TEXT,substring(TG_OP,1,1),v_old_data); > > > RETURN OLD; > > > ELSIF (TG_OP = 'INSERT') THEN > > v_new_data > := ROW_TO_JSON(NEW.*); > > > INSERT INTO audit.logged_actions (schema_name,table_name,user_name,action,new_data,query) > > > VALUES (TG_TABLE_SCHEMA::TEXT,TG_TABLE_NAME::TEXT,session_user::TEXT,substring(TG_OP,1,1),v_new_data); > > > RETURN NEW; > > > ELSE > > > RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - Other action occurred: %, at %',TG_OP,now(); > > > RETURN NULL; > > > END IF; > > > > EXCEPTION > > > WHEN data_exception THEN > > > RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - UDF ERROR [DATA EXCEPTION] - SQLSTATE: %, SQLERRM: %',SQLSTATE,SQLERRM; > > > RETURN NULL; > > > WHEN unique_violation THEN > > > RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - UDF ERROR [UNIQUE] - SQLSTATE: %, SQLERRM: %',SQLSTATE,SQLERRM; > > > RETURN NULL; > > > WHEN OTHERS THEN > > > RAISE WARNING '[AUDIT.IF_MODIFIED_FUNC] - UDF ERROR [OTHER] - SQLSTATE: %, SQLERRM: %',SQLSTATE,SQLERRM; > > > RETURN NULL; > END; > > $body$ > LANGUAGE plpgsql > > > > CREATE TRIGGER > t_if_modified_trg > AFTER > INSERT OR UPDATE OR DELETE ON > temp_tbl > > FOR EACH ROW EXECUTE PROCEDURE audit.if_modified_func();