INTERVIEW QUESTIONS

What is Apex

Ans: It is the in-house technology of salesforce.com which is similar to Java programming with object oriented concepts and to write our own custom logic.

What is S-Control ?
Ans: S-Controls are the predominant salesforce.com widgets which are completely based on Javascript. These are hosted by salesforce but executed at client side. S-Controls are superseded by Visualforce now.

 What is a Visualforce Page ?

Ans: Visualforce is the new markup language from salesforce, by using which, We can render the standard styles of salesforce. We can still use HTML here in Visualforce. Each visualforce tag always begins with “apex” namespace. All the design part can be acomplished by using Visualforce Markup Language and the business logic can be written in custom controllers associated with the Page.

 Will Visual force still supports the merge fields usage like S-control ?

Ans: Yes. Just like S-Controls, Visualforce Pages support embedded merge fields, like the {!$User.FirstName} used in the example.

Where to write Visualforce code ?
Ans: You can write the code basically in 3 ways.

1.        setup->App Setup->Develop->Pages and create new Visulaforce page.

2.        Setup -> My Personal Information -> Personal Information -> Edit check the checkbox development mode. When you run the page like this, https://ap1.salesforce.com/apex/MyTestPage. you will find the Page editor at the bottom of the page. You can write you page as well as the controller class associated with it, there it self.

3.        Using EclipseIDE you can create the Visulaforce page and write the code.

 What are Apex Governor Limits?

Governor limits are runtime limits enforced by the Apex runtime engine. Because Apex runs in a shared, multitenant environment, the Apex runtime engine strictly enforces a number of limits to ensure that code does not monopolize shared resources. Types of limits that Apex enforces are resources like memory, database resources, number of script statements to avoid infinite loops, and number of records being processed. If code exceeds a limit, the associated governor issues a runtime exception.

Do governor limits apply to sandbox instances?

Ans : Governor limits do apply to all Salesforce instances (trial, developer, production or sandbox environments). However code coverage and successful execution of test classes is only enforced when deploying to a production environment.

What is difference in ISNULL and ISBLANK?

ISNULL:

         Determines if an expression is null (blank) and returns TRUE if it is. If it contains a value, this function returns FALSE.

         Text fields are never null, so using this function with a text field always returns false. For example, the formula field IF(ISNULL(new__c) 1, 0) is always zero regardless of the value in the New field. For text fields, use the ISBLANK function instead.

         Multi-select picklist fields are never null in s-controls, buttons, and email templates, so using this function with a multi-select picklist field in those contexts always returns false.

         Empty date and date/time fields always return true when referenced in ISNULL functions.

         Choose Treat blank fields as blanks for your formula when referencing a number, percent, or currency field in an ISNULL function. Choosing Treat blank fields as zeroes gives blank fields the value of zero so none of them will be null.

         Merge fields can be handled as blanks, which can affect the results of components like s-controls because they can call this function.

         When using a validation rule to ensure that a number field contains a specific value, use the ISNULL function to include fields that do not contain any value. For example, to validate that a custom field contains a value of ’1,’ use the following validation rule to display an error if the field is blank or any other number: OR(ISNULL(field__c), field__c<>1)

ISBLANK:

         Determines if an expression has a value and returns TRUE if it does not. If it contains a value, this function returns FALSE.

         Use ISBLANK instead of ISNULL in new formulas. ISBLANK has the same functionality as ISNULL, but also supports text fields. Salesforce.com will continue to support ISNULL, so you do not need to change any existing formulas.

         A field is not empty if it contains a character, blank space, or zero. For example, a field that contains a space inserted with the spacebar is not empty.

         Use the BLANKVALUE function to return a specified string if the field does not have a value; use the ISBLANK function if you only want to check if the field has a value.

         If you use this function with a numeric field, the function only returns TRUE if the field has no value and is not configured to treat blank fields as zeroes.

Is it possible to write the Apex code from user Interface?

You can add, edit, or delete Apex using the Salesforce.com user interface only in a Developer Edition organization, a Salesforce.com Enterprise Edition trial organization, or sandboxorganization. In a Salesforce.com production organization, you can only make changes to Apex by using the Metadata API ,

deploycall, the Force.com IDE, or theForce.com Migration Tool. The Force.com IDE and Force.com Migration Tool are free resources provided by salesforce.com to support its users and partners, but are not considered part of our Services for purposes of the salesforce.com Master Subscription Agreement.

When you can’t add Time dependent action in Workflow rule?
You can’t add time-dependent actions to a rule if you choose Every time a record is created or edited.