My requirement is:

in my login page i have 4 fields.
in one field if i enter phone number then clicking on submit button that phone number is matched to any contact or account phone number then i need to display those records.can any one give some pseudo code for apex class. thanks in advance

in my Scenario, i have picklist field called status, in that picklist field i have multiple values. when i select the picklist field status='approved' and click on the save button then my trigger will run.
here is my trigger:
 for (genesis__Applications__c app1: Trigger.new)
         {     
           
               
              if(app1.genesis__Status__c == 'Approved')
              {
                  
                    application.getDetails(app1.Id);
              }
        }

my requirement is like: this trigger i need to call one time when the trigger is new, suppose if select the status=approved two times and clicking save button, i am getting the result two times with same values.for second time calling the trigger i want to check the trigger whether it is old or new. if it is new , then my class method i need to cal.if it is old then that method no need to cal. can any help me out from this scenario

I have a field like 'Apartmentnumber'.data type number(16,0).
for this i have written validation like this
NOT(REGEX( Apartment_Number__c, "^[0-9]+$"))

i am getting an error
 Incorrect argument type for function 'REGEX().

can any one solve this validation
 

in my Scenario, i have picklist field called status, in that picklist field i have multiple values. when i select the picklist field status='approved' and click on the save button then my trigger will run.
here is my trigger:
 for (genesis__Applications__c app1: Trigger.new)
         {     
           
               
              if(app1.genesis__Status__c == 'Approved')
              {
                  
                    application.getDetails(app1.Id);
              }
        }

my requirement is like: this trigger i need to call one time when the trigger is new, suppose if select the status=approved two times and clicking save button, i am getting the result two times with same values.for second time calling the trigger i want to check the trigger whether it is old or new. if it is new , then my class method i need to cal.if it is old then that method no need to cal. can any help me out from this scenario