Tag Archives: SFDC

Label does not get displayed when inputField is in an actionRegion

Action Region will wrap only the input Field and not the complete pageBlockSectionItem. Place pageBlockSectionItem tags inside a pageBlockSection, which in turn should be in a pageBlock. This will provide the correct formatting.

<apex:page standardController="Campaign" showHeader="true" >
	<apex:form>
		<apex:outputPanel id="op1">
			<apex:pageBlock>
				<apex:pageBlockSection columns="2" title="Information">
					<apex:pageBlockSectionItem>
						<apex:actionRegion>
							<apex:inputField label="{!$ObjectType.Campaign.fields.Category__c.Label}" value="{!Campaign.Category__c}"> 
								<apex:actionSupport event="onchange" rerender="op1" />
							</apex:inputField>
						</apex:actionRegion>
					</apex:pageBlockSectionItem>
				</apex:pageBlockSection>
			</apex:pageBlock> 
		</apex:outputPanel>
	</apex:form>
</apex:page>

Salesforce System Fields

The following fields are Salesforce system fields found on most objects. These fields are read-only and automatically updated during API operations.

Field Field Type Description
Id ID Globally unique string that identifies a record. Because this field exists in every object, it is not listed in the field table for each object. Id fields have Defaulted on create and Filter access.
IsDeleted boolean Indicates whether the record has been moved to the Recycle Bin (true) or not (false). Because this field does not appear in all objects, it is listed in the field table for each object.
Audit Fields
CreatedById reference ID of the User who created this record. CreatedById fields have Defaulted on create and Filter access.
CreatedDate dateTime Date and time when this record was created. CreatedDate fields have Defaulted on create and Filter access.
LastModifiedById reference ID of the User who last updated this record. LastModifiedById fields have Defaulted on create and Filter access.
LastModifiedDate dateTime Date and time when a user last modified this record. LastModifiedDate fields have Defaulted on create and Filter access.
SystemModstamp dateTime Date and time when a user or automated process (such as a trigger) last modified this record. SystemModstamp fields have Defaulted on create and Filter access.

Salesforce Platform APIs

  • REST API: Access objects in your organization using REST.
  • SOAP API: Integrate your organization’s data with other applications using SOAP.
  • Tooling API: Build custom development tools for Force.com applications.
  • Chatter REST API: Access Chatter feeds and social data such as users, groups, followers, and files using REST.
  • Bulk API: Load or delete large numbers of records.
  • Metadata API: Manage customizations in your org and build tools that manage the metadata model (not the data, itself).
  • Streaming API: Provide a stream of data reflecting data changes in your organization.
  • Apex REST API: Build your own REST API in Apex. This API exposes Apex classes as RESTful Web services.
  • Apex SOAP API: Create custom SOAP Web services in Apex. This API exposes Apex classes as SOAP Web services.
  • Data.com API: Data.com provides 100% complete, high quality data, updated in real-time in the cloud, and with comprehensive coverage worldwide.

Salesforce Visualforce Page Lifecycle

Visualforce page’s lifecycle is, how the page is created and destroyed during the period of a user session. The lifecycle of a visualforce page is determined not just by the content of the page, but also by how the page was requested.

When a user views a Visualforce page, instances of the controller, extensions, and components associated with the page are created by the server. The order in which these elements are executed can affect how the page is displayed to the user.

There are two types of Visualforce page requests:

Visualforce Page Get Requests:
A get request is an initial request for a page either made when a user enters an URL or when a link or button is clicked that takes the user to a new page.

Order of Execution for Visualforce Page Get Requests: The following diagram shows how a Visualforce page interacts with a controller extension or a custom controller class during a get request:

In the diagram above the user initially requests a page, either by entering a URL or clicking a link or button. This initial page request is called the get request.

  • The constructor methods on the associated custom controller/extension classes are called, instantiating the controller objects.
  • If the page contains any custom components, they are created and the constructor methods on any associated custom controllers or controller extensions are executed. If attributes are set on the custom component using expressions, the expressions are evaluated after the constructors are evaluated.
  • The page then executes any assignTo attributes on any custom components on the page. After the assignTo methods are executed, expressions are evaluated, the action attribute on the component is apex:pageevaluated, and all other method calls, such as getting or setting a property value, are made.
  • If the page contains an apex:form component, all of the information necessary to maintain the state of the database between page requests is saved as an encrypted view state. The view state is updated whenever the page is updated.
  • The resulting HTML is sent to the browser. If there are any client-side technologies on the page, such as JavaScript, the browser executes them.

Note:

  • Once a new get request is made by the user, the view state and controller objects are deleted.
  • If the user is redirected to a page that uses the same controller and the same or a proper subset of controller extensions, a post back request is made. When a post back request is made, the view state is maintained.

Visualforce Page Postback Requests:
A postback request is made when user interaction requires a page update, such as when a user clicks on a Save button and triggers a save action.
Order of Execution for Visualforce Page Postback Requests: The following diagram shows how a Visualforce page interacts with a controller extension or a custom controller class during a postback request:

  • During a postback request, the view state is decoded and used as the basis for updating the values on the page. (A component with the immediate attribute set to true bypasses this phase of the request. In other words, the action executes, but no validation is performed on the inputs and no data changes on the page.)
  • After the view state is decoded, Expressions are evaluated and set methods on the controller and any controller extensions, including set methods in controllers defined for custom components, are executed. If update is not valid due to validation rule or incorrect data type, data is not updated and page redisplay with error message.
  • Data updated on action there is no evaluation for component attribute. (The action attribute on the component is not evaluated during a postback request. It is only evaluated during a get request.)
  • The resulting HTML is sent to the browser.

Note:

  • Once the user is redirected to another page, the view state and controller objects are deleted.
  • You can use the setRedirect attribute on a pageReference to control whether a postback or get request is executed. If setRedirect is set to true, a get request is executed. Setting it to false does not ignore the restriction that a postback request will be executed if and only if the target uses the same controller and a proper subset of extensions. If setRedirect is set to false, and the target does not meet those requirements, a get request will be made.

System.QueryException: Aggregate query has too many rows for direct assignment, use FOR loop

You might get a QueryException in a SOQL for loop with the message Aggregate query has too many rows for direct assignment, use FOR loop. This exception is sometimes thrown when accessing a large set of child records (200 or more) of a retrieved sObject inside the loop, or when getting the size of such a record set.

For example, the query in the following SOQL for loop retrieves child contacts for a particular account. If this account contains more than 200 child contacts, the statements in the for loop cause an exception.

for (Account acc : [SELECT Id, Name, (SELECT Id, Name FROM Contacts) FROM Account WHERE Id IN ('<ID value>')]) { 
    
}

In order to avoid System.QueryException: Aggregate query has too many rows for direct assignment, use FOR loop, make sure the sub query is limited as follows.

for (Account acc : [SELECT Id, Name, (SELECT Id, Name FROM Contacts LIMIT 200) FROM Account WHERE Id IN ('<ID value>')]) { 
    
}