mysql commonly used triggers, views, stored procedures

View:
CREATE VIEW demo AS SELECT * FROM book
CREATE VIEW: Create a view
AS: SELECT
stored procedure executed :
CREATE PROCEDURE a( IN p INT(10), OUT h INT(10))
BEGIN
SELECT id INTO h FROM book WHERE id = p;
END;
CALL a(4,@h)
SELECT @h
CREATE: Create
PROCEDURE: Stored procedure
BEGIN: Start of code block
END: End of code block
AFTER Trigger:
CREATE TRIGGER P AFTER INSERT ON book FOR EACH ROW
SELECT NEW .id INTO @ee;
CERATE TRIGGER: Create a trigger
AFTER INSERT:
ON after executing the insert operation :
FOR EACH ROW: Executing the code on which table
NEW: Inserted virtual table
BEFORE Trigger:
CREATE TRIGGER O BEFORE DELETE ON book FOR EACH ROW
BEGIN
INSERT INTO book_new value (OLD.id,'Yi Xian','sister’s best friend');
END;
CREATE TRIGGER: Create a trigger
BEFORE DELETE: Before executing DELETE
FOR EACH ROW BEGIN: Start executing code
OLD: Not executing it Inter-data