Salesforce Interview Questions Part#4
1) How do you hide Header and Sidebar on Visualforce page?
2) What is difference between standard and custom controller?
3) What is Controller extension?
4) How do you read parameter in Visualforce page?
5) How many dependent drop down can be put on one Visualforce page?
6) What is the maximum size of the PDF generated on Visualforce attribute renderAs?
7) How to use actionPoller tag?
8. What is difference between actionFunction and actionSupport Tag ?
9) How can we check the object accessibility on visualforce page?
10) How many rows return by list controller?
11) What is custom component?
12) What is assignTo attribute and what is its use?
13. What are Apex Governor Limits?
Ans: 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.
14. How to create and host S Control in Salesforce ?
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)
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.
15. 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 , deploy call, 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.