Salesforce Transaction Control

A transaction is a unit of work that you want to treat as "a whole". It has to either happen in full, or not at all.When it comes to maintain consistency and integrity of data ,Transaction Control is of paramount importance. Transaction control ensures the data changes done in failed operations do not modify the state of your database while changes done by successfully completed operations are reflected in the database.

Salesforce Transaction control is means of enforcing the above concept to your apex code which executes on Salesforce servers.In Salesforce you can do this with two simple methods.

1. Savepoint sp = Database.setSavepoint(); - marks the beginning of your transaction and also the point  to database should revert in case the operation fails.
2. Database.rollback(sp); - undo any changes you have done to the database after the passed save point. This methods takes a save point as a parameter and roll back all the database changes done after the passed save point.

example of  using above methods in code

 // variable initialization   
  // your custom validation logic   
  Savepoint sp = Database.setSavepoint(); // should be before any dml statements that you intend to be undone if the operation fails   
  try   
  {   
  // your dml statements and other logic   
  }   
  catch(Exception e )   
  {   
   //oops something bad happen before opertion completed   
  Database.rollback(sp); //undo any dml change done after setting the save point.   
  }   

you can find more about Salesforce Transaction Control Here

One important point to note is Id values of Sobject records save after save point are not cleared on rollback.Attempting to insert the sObject using the variable created before the rollback fails because the sObject variable has an ID. Updating or upserting the sObject using the same variable also fails because the sObject is not in the database and, thus, cannot be updated.So it is important you reinitialize your sobjects after rollback else it will generate DML exceptions on subsequent operations such as

• Record ID: cannot specify Id in an insert call 
• Record does not exist

Salesforce Record Deletion

In this post I am going to discuss Salesforce record deletion process.In Salesforce once record are deleted those records are moved to the recycle bin and they are no longer accessible through the  SOQL queries or Salesforce standard views.Deleted records are maintained in the recycle bin of 15 days (earlier it was 45 but seems Salesfore has reduced the duration)
refer below link for more details

Salesforce Deleting Records

for more details about recycle bin refer

Salesforce Recycle Bin

All though normal SOQL queries do not return deleted records you can make SOQL queries include deleted records in results by adding "ALL ROWS" keyword at the end of your query.But it is important that you be careful when performing DML operations with such results because the results include deleted records.

example - using ALL ROWS in SOQL

[SELECT COUNT() FROM Contact WHERE AccountId = a.Id ALL ROWS];

In addition to above  approach if you want to explicitly query deleted records only ,you can use "IsDeleted" Standard attribute.

example - using IsDeleted in SOQL

[SELECT Id, Name FROM Account WHERE IsDeleted=true];

Scheduling Your Apex Classes Via Script

One of the most tedious tasks I face during deployment of my code to QA and Production orgs is the removing the scheduled classes and rescheduling them after the release  is completed.As the number of scheduled classes grows this becomes more and more difficult and prone to error as the possibility of  forgetting to reschedule some classes grows.

As I was on the look out  for a solution I found  that classes can be scheduled via apex and I tried writing a script to schedule my classes and to my luck It worked as i expected.As I thought there may be at least few of you who has faced the same issue I thought of sharing my code. Please note that this code may not be directly serve your purpose and will need some tweaking. But it will give you the basic idea of how classes can be scheduled via apex.


list<ApexClass> listClasses;
//create a string list and add the Names of classes you want to schedule
//please note that all of these classes must implement schedulable Interface
List<String> ClassesToBeScheduled = new List<String>(); ClassesToBeScheduled.add('FirstSchedule'); ClassesToBeScheduled.add('SecondSchedule'); ClassesToBeScheduled.add('ThirdSchedule'); ClassesToBeScheduled.add('FouthSchedule');

//query the salesforce apexclass object to get the records of classes you want to //schedule

for(ApexClass ac:[Select Id Name From ApexClass where Name IN:ClassesToBeScheduled]) { String className = ac.Name; String sch ='0 0 4 ? * * 2014'; // expersion specify how class is scheduled

//here the class is scheudled to run at 4.00 AM every day till the end of 2014

// you can learn all about schedule expressions here

Type t = Type.forName(className);

//schedule the class by passing 

//1.jobName - any string (here I use class name)

//2.schedule frequncy - string experssion specify when and hoe often each class //is run

//3.Instance of the class to be scheduled System.schedule(className, sch, (Schedulable)t.newInstance()); }

You can then run your script using developer console.

My Salesforce Credentials

 If you are a professional Salesforce developer on of the best ways to get the deserved recognition is to obtain and maintain Salesforce certification .It is the best way to prove that you are well qualified Salesforce Developer who is up to date with latest platform related knowledge.

I have obtained both Salesforce Developer certifications which are

• Salesforce Certified Developer
• Salesforce Certified Advanced Developer

Salesforce recently provided the option of verifying certification credentials of individuals .Here is screen capture I have taken from certification verification option related to my qualifications.

my Salesforce credentials

Salesforce Work Flow Field Updates make Triggers Run Twice

Salesforce Workflow Rule Field Updates are one of the most useful features provided by the platform for making updating record field values.They are simple and easy to use  but among all positives there is one major downside..That is Workflows make your trigger run twice for a single update

• First time for the actual record update
• Second time for the Workflow field update

To find more details please refer Apex Triggers Order Of Execution . Now you may be wondering Is this bad? . Well it depends on whether you have apex trigger(s) on the object workflow is defined and what that trigger(s) does.If you don't have any triggers on workflow related object there  is nothing to worry but if you have they may have some negative side effects such as

• make your code reach governor limits -for an example if your field update cause your trigger to run 20 Queries with workflow updates it may consume 40.
• Logic Errors - if your trigger send mails or do DML operations , those operations  will get duplicated which results in sending duplicate mails and duplicate record inserts or updates.
• Performance : running same logic twice may hardly do any favors to the application performance. 

To avoid trigger code's duplicate execution you can use Class Level Static Variable

 global Class SingleExecution 

 {  
    public Static boolean HasTriggerAlreadyRun = false;  
    public static boolean HasAlreadyExecuted()  
    {  
      return HasTriggerAlreadyRun ;  
    }  
    public static void SetHasAlreadyExectued()  
    {  
     HasTriggerAlreadyRun = true;   
    }  
 }

  
 Trigger MyobjectTrigger on MyObject__c (before update )  
 {  
   if(SingleExecution.HasAlreadyExecuted())  
   {  
    return;  
   }   
   else  
   {  
    //execute your logic  
   SingleExecution.SetHasAlreadyExectued()  
   }  
 }  

Note :- Checking Old and new values on record fields will not prevent workflow field update related second trigger excection as Salesforce States "Trigger.old contains a version of the objects before the specific update that fired the trigger. However, there is an exception. When a record is updated and subsequently triggers a workflow rule field update, Trigger.old in the last update trigger won’t contain the version of the object immediately prior to the workflow update, but the object before the initial update was made. For example, suppose an existing record has a number field with an initial value of 1. A user updates this field to 10, and a workflow rule field update fires and increments it to 11. In the update trigger that fires after the workflow field update, the field value of the object obtained from Trigger.old is the original value of 1, rather than 10, as would typically be the case."

Learn more about WorkFlow Rule Field Updates Here

  

Salesforce User Record Permission

When it comes to Salesforce what user can or can't do to a record depends on the sharing rights that particular user has on the record.For an example if user want to view a record , that record must be read shared with the user, if he want to edit a  record that record must be edit shared.One important point to note is object permission defines is what Operations are allowed for the user on a particular object on what record(s) that operation is allowed depend on the user record sharing..for a example if a user's profile has edit rights on a object doesn't mean he can edit  all the records of that object but only the records edit shared to him.

So it is much ideal to check what rights users has on a record rather than handling "Insufficient Access" exceptions.The access rights particular user has on a record can be obtained by UserRecordAccess  standard object.

Please note : UserId and RecordId on where clause are required 

SELECT RecordId, HasReadAccess, HasTransferAccess, MaxAccessLevel
     FROM UserRecordAccess
     WHERE UserId = [single ID]
     AND RecordId = [single ID]      //or Record IN [list of IDs]

   eg: check logged users permission on a record with Id "a1100000000000a"

  SELECT  RecordId, HasReadAccess, HasTransferAccess, MaxAccessLevel
 FROM    UserRecordAccess
 WHERE   UserId =:UserInfo.getUserId()
 AND     RecordId='a1100000000000a'


if your record view page is overridden with Visualforce Page and it uses custom controller or extension you can use UserRecordAccess object to show/hide buttons based on user permission.

More Details about UserRecordAccess from here

Salesforce SOQL Query All fields of an Object

Salesforce database query language is SOQL.When writing queries one of the tedious tasks developers face is specifying each and every field you want in queries.Unlike SQL ,SOQL doesnt allow you to query all the fields by using "*" .Salesfroce . Salesforce may have their own reasons for not allowing "*" such as querying all the fields always may affect the performance as well as it may cause you run into view state limits  in visualforce pages.

All though SOQL doesn't allow you the "*" operator you can archive the same using Dynamic SOQL and the Salesforce meta data api.

Lets assume your object Name is MyObject__c

 Map <String, Schema.SObjectType> schemaMap = Schema.getGlobalDescribe();  
 Map <String, Schema.SObjectField> fieldMap = schemaMap.get('MyObject__c').getDescribe().fields.getMap();  
 List<MyObject__c> results;  
 String Query = 'Select';  
 //loop through all object fields and add them to select clause  
 for(Schema.SObjectField sfield : fieldMap.Values())  
  {  
       schema.describefieldresult dfield = sfield.getDescribe();  
       String fieldApexName = dfield.getname();  
       if(Query.equals('Select'))  
       {  
         Query+=' '+fieldApexName;  
       }  
       else  
       {  
         Query+=' ,'+fieldApexName;  
       }  
   }  
 //optionally if you want parent object fields you have to mention each of them the explicitly   
 Query += ',PerentObject__r.FieldName__c ';  
 Query+= ' From MyObject__c '  
 //Optionally if you have a condition they can be added as   
 Query+= ' where Name = myfirstRecord '   
 //return results  
 results = Database.query(Query);  

Learn more about Dynamic SOQL .
Learn more about SOQL