Trigger Context Variable in Salesforce

 a. isExecuting- Genuine if the current setting for the function Apex code is a trigger, not just  Visualforce page, a web benefit, or an execute anonymous() API call.

b. isInsert- Genuine if this trigger was eliminated because of an embed activity, from the Salesforce UI, Apex, or the API.
c. isUpdate- Returns genuine if this trigger was let go because of a refresh task, from the Salesforce UI, Apex, or the API.
d. isDelete- Genuine if this trigger lets go due to the reason of an erase activity, from the Salesforce user interface, Apex, or the API.
e. isBefore- Returns genuine if this trigger terminates before any record was spared.

f. isAfter– Returns genuine if this trigger was terminated after all records were spared.
g. isUndelete- Genuine if this trigger was let go once just after a record is recouped from the Recycle Bin (that is after an undelete task from the Salesforce UI, Apex, or the API.)
h. new- Returns a rundown of the new forms of the sObject records. This sObject list is just accessible in the embed, refresh, and undelete triggers, and the records must be changed in before triggers.
i. newMap- A directory of IDs to the new kind of the sObject records. This guide is just accessible in before refresh, after embed, after refresh, and after undelete triggers.
j. Old- Returns a rundown of the old forms of the sObject records. This sObject list is just accessible in refresh and erases triggers.
k. oldMap- A guide of IDs to the old renditions of the sObject records. This guide is just accessible in refresh and erases triggers.
l. Size- The add up to the number of records in a trigger summon, both old and new.