--- schema_version: "1" id: 4817a36780b6a7154f87d02017f167520010ef51962ce3a12e45ed4c7504f7e3 title: Trigger Class collection: legacydeveloper version: current locale: en-us portal_url: https://docs.salesforce.com/legacydeveloper/current/en-us/apexref/apex_class_System_Trigger.md canonical_url: https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Trigger.htm source_site: developer.salesforce.com content_type: documentation content_hash: d5043589510d2e7d89bd46aa6a55a107247eadb1c91ab7c86fab7253bfd32c1c description: Use the Trigger class to access run-time context information in a trigger, such as the type of trigger or the list of sObject records that the trigger operates on. --- # Trigger Class Use the Trigger class to access run-time context information in a trigger, such as the type of trigger or the list of sObject records that the trigger operates on. ## Namespace [System](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_namespace_System.htm "The System namespace provides classes and methods for core Apex functionality.") ## Trigger Context Variables The Trigger class provides the following context variables.
Variable Usage
isExecuting Returns true if the current context for the Apex code is a trigger, not a Visualforce page, a web service, or an executeanonymous() API call.
isInsert Returns true if this trigger was fired due to an insert operation, from the Salesforce user interface, Apex, or the API.
isUpdate Returns true if this trigger was fired due to an update operation, from the Salesforce user interface, Apex, or the API.
isDelete Returns true if this trigger was fired due to a delete operation, from the Salesforce user interface, Apex, or the API.
isBefore Returns true if this trigger was fired before any record was saved.
isAfter Returns true if this trigger was fired after all records were saved.
isUndelete Returns true if this trigger was fired after a record is recovered from the Recycle Bin. This recovery can occur after an undelete operation from the Salesforce user interface, Apex, or the API.
new Returns a list of the new versions of the sObject records.

This sObject list is only available in insert, update, and undelete triggers, and the records can only be modified in before triggers.
newMap A map of IDs to the new versions of the sObject records.

This map is only available in before update, after insert, after update, and after undelete triggers.

old Returns a list of the old versions of the sObject records.

This sObject list is only available in update and delete triggers.
oldMap A map of IDs to the old versions of the sObject records.

This map is only available in update and delete triggers.

operationType Returns an enum of type System.TriggerOperation corresponding to the current operation.

Possible values of the System.TriggerOperation enum are: BEFORE_INSERT, BEFORE_UPDATE, BEFORE_DELETE,AFTER_INSERT, AFTER_UPDATE, AFTER_DELETE, and AFTER_UNDELETE. If you vary your programming logic based on different trigger types, consider using the switch statement with different permutations of unique trigger execution enum states.
size The number of records processed in a trigger invocation. DML operations that include over 200 records are processed in batches, and the trigger is invoked for each batch. Trigger.size includes only the number of records in the current batch, not the total number of records in the DML operation.
![Note](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/images/icon_note.png) #### Note The record firing a trigger can include an invalid field value, such as a formula that divides by zero. In this case, the field value is set to null in these variables: - new - newMap - old - oldMap ## Example For example, in this simple trigger, Trigger.new is a list of sObjects and can be iterated over in a for loop. It can also be used as a bind variable in the IN clause of a SOQL query. trigger SimpleTrigger on Account(after insert) { for (Account a : Trigger.new) { // Iterate over each sObject } // This single query finds every contact that is associated with any of the // triggering accounts. Note that although Trigger.new is a collection of // records, when used as a bind variable in a SOQL query, Apex automatically // transforms the list of records into a list of corresponding Ids. Contact\[\] cons = \[ SELECT LastName FROM Contact WHERE AccountId IN :Trigger.new WITH USER\_MODE \]; } This trigger uses Boolean context variables such as Trigger.isBefore and Trigger.isDelete to define code that only executes for specific trigger conditions: trigger MyAccountTrigger on Account( before delete, before insert, before update, after delete, after insert, after update ) { if (Trigger.isBefore) { if (Trigger.isDelete) { // In a before delete trigger, the trigger accesses the records that will be // deleted with the Trigger.old list. for (Account a : Trigger.old) { if (a.name != 'okToDelete') { a.addError('You can\\'t delete this record!'); } } } else { // In before insert or before update triggers, the trigger accesses the new records // with the Trigger.new list. for (Account a : Trigger.new) { if (a.name == 'bad') { a.name.addError('Bad name'); } } if (Trigger.isInsert) { for (Account a : Trigger.new) { Assert.areEqual('xxx', a.accountNumber); Assert.areEqual('industry', a.industry); Assert.areEqual(100, a.numberofemployees); Assert.areEqual(100.0, a.annualrevenue); a.accountNumber = 'yyy'; } // If the trigger is not a before trigger, it must be an after trigger. } else { if (Trigger.isInsert) { List contacts = new List(); for (Account a : Trigger.new) { if (a.Name == 'makeContact') { contacts.add(new Contact(LastName = a.Name, AccountId = a.Id)); } } insert as user contacts; } } } } }