database-trigger

问题 So we're looking for a way to enforce constraints that span multiple tables. We've come across this old blog post, which suggests: Create a materialized view to select data that violates the desired constraint. The MV must be defined with REFRESH COMPLETE ON COMMIT so that it is updated before the end of the transaction. Create a check constraint on the materialized view that always evaluates to FALSE – e.g. CHECK (1=0) That’s it. Whenever the underlying tables are updated, the materialized

问题 So we're looking for a way to enforce constraints that span multiple tables. We've come across this old blog post, which suggests: Create a materialized view to select data that violates the desired constraint. The MV must be defined with REFRESH COMPLETE ON COMMIT so that it is updated before the end of the transaction. Create a check constraint on the materialized view that always evaluates to FALSE – e.g. CHECK (1=0) That’s it. Whenever the underlying tables are updated, the materialized

问题 Please help with my understanding of how triggers and locks can interact I bulk load records to a table with statements something like this….. BEGIN; INSERT INTO table_a VALUES (record1) , (record2), (record3)………; INSERT INTO table_a VALUES (record91) , (record92), (record93)………; ….. …. COMMIT; There can be several hundred records in a single insert, and there can be several dozen INSERT statements between COMMITs Table_a has a trigger on it defined as…. AFTER INSERT ON table_a FOR EACH ROW

问题 Wrote a trigger function that inserts full documents to my collection new_list when ever there is an insert into listingsAndReviews collection. exports = function(changeEvent) { const fullDocument = changeEvent.fullDocument; const collection = context.services.get('Cluster0').db("sample_airbnb").collection("new_list"); return collection.insertMany([fullDocument]) .then(result => { console.log(`Successfully inserted ${result.insertedIds.length} items!`); return result; }) .catch(err => console

问题 I have the following table: CREATE TABLE booking( booking_id NUMBER(8) NOT NULL; booking_start DATE NOT NULL; booking_end DATE NOT NULL; booking_room NUMBER(3) NOT NULL; guest_no NUMBER(5) NOT NULL; ); This table keeps track of all bookings for rooms in a particular hotel. I want to write a trigger to prevent bookings being added that overlap with the dates of previous bookings for particular rooms in the hotel. For example, let's say that room 5 is currently booked from 01 Jan 2019 to 07 Jan

问题 I've just started to learn SQL a few weeks ago and I'm trying to make a trigger which changes the inserted value into 10 if it's smaller than 10. I searched for 4h now and I've found a lot of answers but none was good(for me). I really don't understand where the problem is. Here is the code: CREATE OR REPLACE TRIGGER NumberOfBooks BEFORE INSERT ON Book FOR EACH ROW BEGIN IF new.nobook < 10 THEN SET new.nobook = 10; END IF; END; 回答1: In Oracle's trigger syntax the newly inserted record is

问题 I have a SQL Azure database with one table on Azure and I want to trigger my notification hub when there is a change in the number of rows on my table so that I can send a push notification to my universal app. I tried to trigger a WCF service so that I can then call my notification hub but with no luck. Also I don't think is the best way either anyway. Do you have any thoughts? 回答1: i think that you can try using Logic Apps in this case linked to your services, so whenever there is a new row

问题 I have several databases that are used by several applications (one of which is our own, the others we have no control over in what they do). Out software has to know when the database has last been changed. For reasons I won't get into to keep this short we decided that going with a new table per database that has a singular field: last_changed_on that has a GetDate() as a value. This way our own software can check when it was last changed and check it to the date it has stored for said

问题 This question already exists : DBMS output not being flushed after trigger? Closed 5 months ago . I am using oracle SQL developer and I have an AFTER UPDATE ON trigger that I would like to get some debug output from, something like 'Inserted 5 rows into table A'; I have tried doing this with dbms_output, calling dbms_ouput.put_line('mytext') with the text that I want printed. However, even when my trigger activates, I don't get any output on the dbms output windows (yes I have enabled dbms

问题 Here is a code for trigger and it have a for loop. When trigger is fired (INSERT OR UPDATE) there's another table data must include it is MICL_SUP OPEN projMgrsCursor; LOOP FETCH projMgrsCursor INTO projMgr; select micl_sup_id_seq.nextval into SUPID from dual; insert into MICL_SUP VALUES ((SUPID), (SELECT SYSDATE FROM DUAL), :NEW.ENTRYADDEDBY_EMP_NO, 3000, 0,projMgr, NULL,:NEW.EMP_NO); END LOOP; CLOSE projMgrsCursor; This is the table structure. Sup_ID primary and unique key . I can't make