how to create trigger

Definition: What is a trigger? In SQL Server, certain operations on a table trigger certain conditions to execute a program. A trigger is a special stored procedure.There are three common triggers: Insert, Update, and Delete events.Why should I use

/* Create a virtual test environment, including the table [cigarette inventory table] and table [cigarette sales table]. Please pay attention to tracking the data of these two tables and understanding what business logic the trigger has executed and

OverviewA trigger, as the name implies, executes a program when something (event) occurs. Triggers have four main elements:,,, 监视地点（table_name） 监视事件（insert/update/delete） 触发时间（before/after）触发执行程序（insert/update/delete）Grammar #创建触发器 Create trigger

Trigger The trigger is the database application Reuse tool, its application is very extensive, these days writes a chemical data statistics aspect software, needs according to the sampling, calculates the variance automatically, here, I use the

1. IndexThe index is the equivalent of a book directory, which helps users quickly find what they need.The database can greatly improve the query efficiency by using a variety of rapid localization techniques. In particular, when the amount of data

Trigger (Trigger): Monitors a situation and triggers an action.Trigger creation Syntax four elements: 1. Watch Location (table) 2. Monitoring Event (Insert/update/delete) 3. trigger Time (After/before) 4. Trigger Event (insert/update/delete)

Read Catalogue One: Advantages of triggers II: The role of triggers Three: the classification of triggers Four: how triggers work V: Create a trigger VI: Manage triggers Concept:?? A trigger (trigger) is a method

Trigger (Trigger): Monitors a situation and triggers an action.Trigger creation Syntax four elements: 1. Monitoring location (table) 2. Monitoring Events (Insert/update/delete) 3. Trigger Time (After/before) 4. Trigger Event

MySQL Trigger TriggerTrigger (Trigger): Monitors a situation and triggers an action.Trigger creation Syntax four elements: 1. Monitoring location (table) 2. Monitoring Events (Insert/update/delete) 3. Trigger Time (After/before) 4. Trigger Event

Create:[SQL]View PlainCopy Create Trigger Trigger_name ON {table_name View_name} {for after Instead of } [ Insert, Update,delete] As Sql_statement To delete a trigger:[SQL]View PlainCopy Drop Trigger

Stored Procedures1, stored procedures are prepared in advance, stored in the database of the program, these programs to complete the database of the specified operation.2. System stored procedure: SQL Server itself provides a number of stored

Here's an excerpt of a text description of the trigger in the official SQL Server tutorial, which is really useful. You can define a trigger that executes whenever you insert data into a table with an INSERT statement. When the insert trigger is

Common functions for MySQL stored procedures A. String classCHARSET (str)//return string character setCONCAT (string2 [,...])//connection stringINSTR (string, substring)//Returns the position that substring first appeared in string and does not

What is a trigger? A trigger is a database program that listens to an action on a data table, and executes the SQL statement as soon as the behavior of the datasheet occurs. syntax structure of triggers: Create TRIGGER Trigger Name trigger

A trigger (trigger) is a method that SQL Server provides to programmers and data analysts to ensure data integrity. It is a special stored procedure associated with a table event, and its execution is not invoked by the program or initiated manually,

MySQL Trigger syntax:Trigger trigger is a special stored procedure that triggers execution when inserting (inset), deleting (delete), or modifying (update) data in a particular table, which is more granular and more complex than the data itself. A

Copy table structure + table dataMysql> Create tables t2 like T1;mysql> INSERT INTO T2 select * from T1; MySQL IndexA, Alert Table is used to create a normal index, unique unique index (the current column value is not repeatable) or Primary key

The test is important. We can know which tables are affected by the current transaction-used to record when and what operations the user performs on the current table: update, insert, deletecreatetableTriggerRecord (operdtdatetime, -- trigger time

Insert trigger example createtriggertri_insertonstudentforinsertasdeclare @ student_idchar (10) select @ student_0000000001beginraiserro Insert trigger example create trigger tri_insert on student for insert as declare @ student_id char (10) select @

Mysql trigger operation: mysql trigger operationTrigger operation: 1. trigger creation: (1 ). create trigger trigger_name before | after trigger_event on table_name for each row trigger_stmt; trigger_event indicates the Operation Event (insert,