Intermediate 30 min read

Schema Describe Basics

By the end of this lesson, you'll be able to:

Use Schema methods to inspect an object or field's metadata at runtime
Check whether a field is accessible or updateable before using it
Explain why describe calls are useful for building genuinely reusable Apex

Prerequisites: "Dynamic sObjects"

Describing an object

Schema.DescribeSObjectResult accountDescribe = Account.sObjectType.getDescribe();

System.debug(accountDescribe.getLabel());       // "Account"
System.debug(accountDescribe.isCreateable());   // true or false, depending on permissions

Schema.DescribeSObjectResult accountDescribe = Account.sObjectType.getDescribe(); — getDescribe() returns metadata about the Account object itself — not a specific record, but facts about the object type.
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System.debug(accountDescribe.getLabel()); — logs "Account", the object's label.
System.debug(accountDescribe.isCreateable()); — logs whether the current running context is even allowed to create one.

Describing a field

Schema.DescribeFieldResult industryField =
    Account.Industry.getDescribe();

System.debug(industryField.getLabel());      // "Industry"
System.debug(industryField.getType());       // PICKLIST
System.debug(industryField.isAccessible());  // true or false

Schema.DescribeFieldResult industryField = — the same idea applies at the field level.
Account.Industry.getDescribe(); — metadata about the Industry field, independent of any particular Account record's actual Industry value.
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System.debug(industryField.getLabel()); — logs "Industry", the field's label.
System.debug(industryField.getType()); — logs PICKLIST, its data type.
System.debug(industryField.isAccessible()); — logs whether it's currently readable.

Why this matters: checking access before using a field

if (Account.Industry.getDescribe().isUpdateable()) {
    acc.Industry = 'Retail';
    update acc;
} else {
    System.debug('Current user cannot update the Industry field.');
}

if (Account.Industry.getDescribe().isUpdateable()) { — rather than assuming every user running this code has permission to update Industry, checks isUpdateable() first.
acc.Industry = 'Retail'; — only runs if permitted.
update acc; — saves the change.
} else { — otherwise...
System.debug('Current user cannot update the Industry field.'); — ...reacts gracefully instead of failing with a permissions error partway through.
} — closes the if/else.

Genuinely reusable code that adapts to who's actually running it — a concept a later Security module builds on significantly.

Exercise

Write code that describes the Contact object and debugs its label using getLabel().

Show hint

Contact.sObjectType.getDescribe().getLabel()

Salesforce: ○ Not connected Connect

APEX

Execution Results

Run your code to see the result.

Schema Describe Basics Quiz

1. What does a Schema describe call provide?

Metadata about an object or field itself — label, type, accessibility — not a specific record's data The actual data stored in a specific record A list of every record in the object A SOQL query result

My Notes

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Summary

Schema describe calls let Apex inspect an object or field's own metadata at runtime — its label, its type, whether the current user can even see it — rather than assuming.

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