triggers in mongodb

WPF triggers, property triggers, event triggers, event triggers.

This paper mainly deals with the application examples of DDL triggers and login triggers. MicrosoftSQL Server provides two primary mechanisms for enforcing business rules and data integrity: constraints and triggers. Triggers are special types of stored procedures that can take effect automatically when a language eve

First, what is a trigger?A trigger (Trigger) is a part of a program that completes the corresponding logical function when a condition is met. In the current WPF, there are altogether three types of trigger, which are: (1) property triggers: Their corresponding classes are trigger. It is triggered when a particular associated property has changed. (2) Data trigger: Its corresponding class is DataTrigger. It is triggered when a value recorded by a part

MySQL Optimization-triggers and mysql triggers Reprinted please indicate the source: http://blog.csdn.net/l1028386804/article/details/46763665 A trigger is a special stored procedure. The difference is that the stored procedure must be called by CALL, and the trigger does not need to use CALL. It does not need to be started manually. As long as a predefined event occurs, it will be automatically called by M

Basic syntax and functions of triggers in SQLSever, and sqlsever triggers What is a trigger? A trigger is a stored procedure that is automatically executed when a table is inserted, updated, or deleted. A special stored procedure that is automatically executed when a trigger inserts, updates, or deletes a table. Triggers are generally used for constraints with mo

Let's look at the database -- (3) triggers and database triggers.Concept: A trigger, as its name implies, is triggered by an event. For example, when we operate a table, it will be activated for execution. When talking about triggers, another key point is to "maintain data integrity ". What does it mean? For example, the business requirement is that when we cancel a card number, we also delete the card's re

Myth #4: DDL triggers (introduced after SQL Server 2005) are instead OF triggers This is wrong. The implementation principle of DDL triggers is actually an after trigger. This means that the DDL operation occurs first, and then the trigger catches the action (of course, if you write a rollback in the trigger, it can be rolled back). The presence of rollba

MySQL learning-triggers, MySQL learning-triggers MySQL supports triggers. A trigger is a database object related to table operations. When a specified event occurs on the table where the trigger is located, this object is called, that is, the Operation Event of the table triggers the execution of the trigger on the tab

After and Instead of triggers, instead triggers L After triggers: these triggers are activated and executed only after the record has been changed. They are mainly used to record the processing or check After the change. Once an error is found, you can also use the Rollback Transaction statement to roll back the operat

Triggers, oracle triggersDirectory I. DML triggers Ii. INSTEAD_OF trigger Iii. system triggers 4. Delete trigger modify trigger status close open -- Description -- 1. BEFORE the event (BEFORE) AFTER the event (AFTER) -- 2. trigger Condition Clause WHEN--3. STATEMENT-level (STATEMENT) Trigger and ROW-level (ROW) trigger -- 3.1 STATEMENT: When a trigger event occur

Concepts and writing of Oracle triggers, and writing of oracle triggers1.Trigger concept: A trigger is a program unit stored on the server. When some events in the database occur (such as insert \ update \ delete), the database automatically starts the trigger and executes the corresponding operations in the trigger. (1) A trigger is a special stored procedure with the transaction function; (2) A trigger cannot be called directly, but is triggered by

(15) mysql triggers and 15mysql triggers Overview A trigger, as its name implies, executes a program when something (event) occurs. Triggers have four main elements:Monitored location (table_name),Monitoring event (insert/update/delete),Trigger time (before/after),Trigger execution Program (insert/update/delete) Syntax # Create trigger triggerName trigger time mo

I. What triggers 1. Personal UnderstandingA trigger, literally, is a trigger. For example, if it is dark, you turn on the light and you see something. You put a gun on it and lit it up. It will blow up later.2. official definitionA trigger is a special stored procedure. Its execution is not called by a program or started manually, but triggered by an event. For example, when a table is operated (insert, delete, update) will activate it for execution.

Basic MySQL triggers (6) and mysql triggers 1. Why trigger: In a MySQL database, a database object table is a logical structure for storing and operating data, and a database object trigger is used to perform an operation triggered by some table events. In the database system, when a table event is executed, the trigger is activated to execute the operations contained by the executor. Trigger operations inc

1. Trigger:Concept:It can be seen as a special process, which is automatically executed and does not allow parameters to be included.The trigger can be used to automatically perform some operations, such as row triggers and data triggers. It is mainly a trigger for Data Control languages.2. transactions:Concept: to ensure data integrity. One or more SQL statements are used to form a logical unit. Then execu

ArticleDirectory 1. Disable, enable, and delete triggers 2. Create a disabled trigger 4. Check the validity of the trigger. 1. Disable, enable, and delete triggers Alter triggerTrigger_nameDisable; Alter triggerTrigger_name enAble; Drop triggerTrigger_name; Example: Disable or enable all triggers on a table Create or replace procedure s

[SQL] -- triggers, SQL triggersConcept Trigger is a method provided by SQL server to programmers and data analysts to ensure data integrity. It is a special stored procedure related to table events, its execution is not called by a program, nor is it manually started, but triggered by an event. For example, when a table is operated (insert, delete, update), it is activated for execution. Triggers are often

Database-create databases, basic tables, and views, Use triggers, and view triggers I. Create a database Create database database_name; // create a database Drop database database_name; // delete a database Ii. Create a basic table 1. Create a table Create table Name ( Field name 1 Data Type [not null] [default value], Field name 2 data type, Field name 3 Data Type ); For example: Create table student ( Stu

Database Operations-triggers, databases-triggers A trigger is a special type of stored procedure. Unlike a stored procedure, a trigger is triggered by an event and automatically called for execution, the stored procedure can be called by the name of the stored procedure. Trigger 1. after trigger 2. insert trigger 3. update trigger 4. delete trigger A trigger is a stored procedure that is automatically execu

Oracle uses triggers to implement auto-increment columns, and oracle uses triggers Oracle uses triggers to implement auto-increment Columns Oracle does not have the auto-increment function. mysql and sqlserver use auto_increment and identity () to implement auto-increment respectively. Oracle can only be implemented through sequences. During each insertion, it i