Writing Apex Trigger : Issues and Solutions ( Cyclic Trigger )

Hi All,

Some times we have a situation where trigger on a event of one object fires another trigger and logic in that trigger again fires first trigger. These situations are called cyclic triggers.
Ex :

trigger Trigger1 on Account (after update) 
    {
        
        for(Account acc : Trigger.New)
            {   
                //Trigger Action Logic
                List<Contact> listCon = [Select Fax from Contact where AccountId =: acc.id];      
                for(Contact con : listCon)
                    {
                        con.Fax = acc.Fax;
                    }
                update listCon;    
           
            }
    }

Another trigger on Contact object update is written like :

trigger Trigger2 on Contact (after update) 
    {
        
        for(Contact con  : Trigger.New)
            {   
                //Trigger Action Logic
                List<Account> accList = [Select Phone from Account where id =: con.AccountId];      
                for(Account acc : accList)
                    {
                        acc.Phone = con.Phone;
                    }
                update accList;    
           
            }
    }

In Above example event in Trigger1 invokes Trigger2 and event in Trigger2 again invokes Trigger1.

Solution : If we use entry criteria as explained in earlier post then cyclic trigger problem will be solved.
Writing Apex Trigger : Issues and Solutions ( Entry Criteria)