triggers

问题 I am trying to implement the equivalent of the "ON UPDATE CURRENT_TIMESTAMP" MySQL feature in sqlite. My idea it to use a trigger like this: CREATE TRIGGER last_update_trigger AFTER UPDATE ON mytable FOR EACH ROW BEGIN UPDATE mytable SET last_update = CURRENT_TIMESTAMP WHERE id = old.id; END But there's a problem with this. Each time an update occurs on a record of this table, the trigger triggers a new update on this same record. This should trigger the trigger again, and again, leading to

问题 I have a Java web app (WAR deployed to Tomcat) that keeps a cache ( Map<Long,Widget> ) in memory. I have a Postgres database that contains a widgets table: widget_id | widget_name | widget_value (INT) (VARCHAR 50) (INT) To O/R map between Widget POJOs and widgets table records, I am using MyBatis. I would like to implement a solution whereby the Java cache (the Map) is updated in real-time whenever a value in the widgets table changes. I could have a polling component that checks the table

问题 I have a requirement to mirror insert/update/delete operations from one table to another. For example insert on tableA has to be copied into tableB, update to tableA applied to tableB, and delete from tableA be applied to tableB. It's as simple as that, except tableB has 1 additional column for a constant value, so very simple triggers are needed. I'm not sure if it is better to write 3 separate triggers, or have one trigger that does all of the operations. This is for 3 databases: Sybase ASE

问题 Hello is possible to switch between DML commands/operations (Insert,Delete,Update) on Trigger Body?, I try to snippet some T-SQL for understand me better : CREATE TRIGGER DML_ON_TABLEA ON TABLEA AFTER INSERT,DELETE,UPDATE AS BEGIN SET NOCOUNT ON; CASE WHEN (INSERT) THEN -- INSERT ON AUX TABLEB WHEN (DELETE) THEN -- DELETE ON AUX TABLEB ELSE --OR WHEN (UPDATE) THEN -- UPDATE ON AUX TABLEB END END GO Thanks, 回答1: I will show you a simple way to check this in SQL Server 2000 or 2005 (you forgot

问题 Lets say I want to store users and groups in a MySQL database. They have a relation n:m. To keep track of all changes each table has an audit table user_journal, group_journal and user_group_journal. MySQL triggers copy the current record to the journal table on each INSERT or UPDATE (DELETES are not supported, because I would need the information which application user has deleted the record--so there is a flag active that will be set to 0 instead of a deletion). My question/problem is:

问题 I get a weird error while trying to create a trigger in my Oracle 11g database using SQL Developer. Here is what I did: My table: CREATE TABLE COUNTRY_CODE( ID NUMBER(19,0) PRIMARY KEY NOT NULL, Code VARCHAR2(2) NOT NULL, Description VARCHAR2(50), created TIMESTAMP DEFAULT CURRENT_TIMESTAMP, created_by VARCHAR2(40) DEFAULT USER, last_updated TIMESTAMP DEFAULT CURRENT_TIMESTAMP, last_updated_by VARCHAR2(40) DEFAULT USER, archived CHAR(1) DEFAULT '0' NOT NULL ); The Sequence: CREATE SEQUENCE

问题 I have never created a trigger in Oracle before so I am looking for some direction. I would like to create a trigger that increments an ID by one if the ID isnt in the insert statement. The ID should start at 10000, and when a record is inserted the next ID should be 10001. If the insert statement contains a ID, it should override the auto increment. ie insert into t1 (firstname, lastname) values ('Michael','Jordan'),('Larry','Bird') should look like: firstname lastname id Micahel Jordan

问题 I have never created a trigger in Oracle before so I am looking for some direction. I would like to create a trigger that increments an ID by one if the ID isnt in the insert statement. The ID should start at 10000, and when a record is inserted the next ID should be 10001. If the insert statement contains a ID, it should override the auto increment. ie insert into t1 (firstname, lastname) values ('Michael','Jordan'),('Larry','Bird') should look like: firstname lastname id Micahel Jordan

问题 First, we currently have the behavior that's desired, but it's not trivial to maintain when any changes to the database are needed. I'm looking for anything simpler, more efficient, or easier to maintain (anything that does any of those 3 would be most welcome). When we perform an update, a history row is created that is a copy of the current row, and the current row's values are then updated. The result being that we have a history record of how the row was before it was updated. Reasoning:

问题 I have two Windows for an application. One of them is MainWindow and the other is for settings. SettingsWindow opens when settings button is clicked by using ShowDialog and setting its Owner to MainWindow . On the SettingsWindow I have a button at the very bottom of the window and it changes the color to red when IsMouseOver is True and blue for False . But it doesn't change when the cursor is over the MainWindow. The image is below to be clear. How can I fix this problem? CASE: The cursor is