H. Integration features

Question 1

What is an external ID in Salesforce? Which all field data types can be used as external IDs?

Answer 1

An external ID is a custom field which can be used as a unique identifier in a record. External IDs are mainly used while importing records/ data. When importing records, one among the many fields in those records need to be marked as an external ID (unique identifier).

An important point to note is that only custom fields can be used as External IDs. The fields that can be marked as external IDs are: Text, Number, E-Mail and Auto-Number.

Question 2

How many callouts to external service can be made in a single Apex transaction?

Answer 2

Governor limits will restrict a single Apex transaction to make a maximum of 100 callouts to an HTTP request or an API call.

Question 3

How can you expose an Apex class as a REST WebService in Salesforce?

Answer 3

You can expose your Apex class and methods so that external applications can access your code and your application through the REST architecture. This is done by defining your Apex class with the @RestResource annotation to expose it as a REST resource. You can then use global classes and a WebService callback method.

Invoking a custom Apex REST Web service method always uses system context. Consequently, the current user’s credentials are not used, and any user who has access to these methods can use their full power, regardless of permissions, field-level security, or sharing rules.

Developers who expose methods using the Apex REST annotations should therefore take care that they are not inadvertently exposing any sensitive data. Look at the below piece of code for instance

global class AccountPlan {
 webservice String area; 
 webservice String region; 
 //Define an object in apex that is exposed in apex web service
 global class Plan {
 webservice String name;
 webservice Integer planNumber;
 webservice Date planningPeriod;
 webservice Id planId;
 }
 webservice static Plan createAccountPlan(Plan vPlan) {
 //A plan maps to the Account object in salesforce.com. 
 //So need to map the Plan class object to Account standard object
 Account acct = new Account();
 acct.Name = vPlan.name;
 acct.AccountNumber = String.valueOf(vPlan.planNumber);
 insert acct;
 vPlan.planId=acct.Id;
 return vPlan;
 } }