System.QueryException: List has no rows for assignment to SObject

Question

while creating the account record am getting this error at Class.MyController.: line 5, column 1 please help me to resolve

 <apex:page STAndardController="account" extensions="MyController"  tabStyle="Account">
   <apex:form >
      <apex:pageBlock title="Congratulations {!$User.FirstName}">
         You belong to Account Name: <apex:inputField value=" {!account.name}"/>
        <apex:commandButton action="{!save}" value="save"/>
    </apex:pageBlock>
  </apex:form>  
 </apex:page>

CONTROLLER

public class MyController
{
     public  Account account{get; set;} 
     public MyController(ApexPages.StandardController controller) 
     {
         account=[SELECT ID,Name, site FROM Account 
                   WHERE Id=:Apexpages.currentPage().getParameters().get('id')]; 
     } 

     public MyController()
     {
           account=[SELECT ID,Name, site FROM Account 
                     WHERE Id=:Apexpages.currentPage().getParameters().get('id')];
     } 
     public Account getAccount()
     {
        return  account ;
     }
     public  void save()
     {
        update account;
     } 
}

Answer 1

from security perspective you must always validate url params. Also standard controller has useful method getId();

Here it is a small example:

public with sharing class AccountController {

public  Account account{ get; set; }

public AccountController(ApexPages.StandardController controller) {
    Id accId = controller.getId();
    if (accId == null) {
        return;
    }
    this.account = [SELECT ID, Name FROM Account WHERE Id =: accId];
}

public AccountController() {
    String tmpId = Apexpages.currentPage().getParameters().get('id');
    System.debug(tmpId);
    if (String.isBlank(tmpId)) {
        return;
    }
    Id accId;
    try {
        accId = Id.valueOf(tmpId);
    }
    catch (Exception e) {
        return;
    }
    List<Account> accs = [SELECT ID, Name FROM Account WHERE Id =: accId LIMIT 1];

    if (!accs.isEmpty()) {
        this.account = accs[0];
    }
}

}

Answer 2

Following query is causing the issue:

account=[SELECT ID,Name, site FROM Account WHERE    Id=:Apexpages.currentPage().getParameters().get('id')];

Either you make sure you have passed correct id in Id parameter or use List<Account> instead of account instance variable.

Answer 3

An alternative solution:

public with sharing AccountController {
  private ApexPages.StandardController ctlr;

  public Account account {
    get {
      try {
           this.account = this.ctlr == null
                        ? [select id, ... from Account where id = : Apexpages.currentPage().getParameters().get('id') limit 1]
                        : (Account) this.ctlr.getRecord();
      }
      catch (QueryException e) {ApexPages.addMessage(...); this.account = new Account();}
      return this.account;
    }
    set;
  }

  public AccountController(ApexPages.StandardController ctlr) {this.ctlr = ctlr;}

  public AccountController() {}
}

It is not clear to me why you have two constructors for this - one as a controller extension and one as a custom controller but I'll assume that is the intent.

The above alternative solution lets the getters do the work rather than constructors, where I tend to like short and simple ones.