Id

Lesson 51 of 51 Salesforce Apex Beginner

Learning Content

Last updated: August 03, 2026

Id Data Type

The Id data type is a Salesforce-specific primitive data type used to uniquely identify every record stored in the Salesforce platform. Whether it is an Account, Contact, Opportunity, Case, Lead, or any custom object, each record is assigned a unique Id when it is created.

Although a Salesforce record Id looks like text, it should be stored using the Id data type instead of a String. The Id data type provides type safety and allows Salesforce to validate record identifiers automatically.

Every Salesforce developer works with record Ids daily while writing Apex, SOQL queries, Triggers, Flows, Lightning Web Components, and integrations.

💡 LearnFrenzy Insight

Think of an Aadhaar number, passport number, or employee ID. Many people may have the same name, but their identification number is always unique. Similarly, Salesforce uses a unique Id to identify every record in the database. Two Accounts can have the same company name, but they will never share the same Salesforce Id.

What is an Id?

An Id uniquely identifies a Salesforce record. It is automatically generated by Salesforce when a new record is inserted into the database.


Account acc = new Account();

acc.Name = 'LearnFrenzy';

insert acc;

Id accountId = acc.Id;

System.debug(accountId);

Salesforce Record Id Formats

Salesforce commonly uses two formats for record Ids.

Type	Length	Description
Case-Sensitive Id	15 Characters	Mainly used within the Salesforce user interface.
Case-Insensitive Id	18 Characters	Commonly used in APIs, integrations, and external systems.

Variable Declaration

Id accountId = '0015g00000ABCDEFGA';

System.debug(accountId);

The value above is an example only. Every Salesforce record receives its own unique Id.

Obtaining a Record Id


Account accountRecord =

[
    SELECT Id, Name
    FROM Account
    LIMIT 1
];

Id recordId = accountRecord.Id;

System.debug(recordId);

Using Id in SOQL


Id accountId = '0015g00000ABCDEFGA';

Account accountRecord =

[
    SELECT Name
    FROM Account
    WHERE Id = :accountId
];

System.debug(accountRecord.Name);

Real Salesforce Business Example

🏢 Business Scenario A customer support application receives an Account Id from a Lightning Web Component and retrieves the Account details.

public static Account getAccount(Id accountId)
{

    return
    [
        SELECT Id, Name, Industry

        FROM Account

        WHERE Id = :accountId
    ];

}

Using the Id data type clearly indicates that the parameter must contain a valid Salesforce record identifier.

Common Salesforce Use Cases

Business Requirement	Example
Retrieve Account	Account Id
Update Opportunity	Opportunity Id
Delete Contact	Contact Id
Create Relationship	Parent Record Id
REST API Integration	Record Identifier
Lightning Navigation	Record Page Id

Id vs String

Id	String
Stores Salesforce record identifiers.	Stores general text.
Automatically validated by Salesforce.	No record validation.
Type-safe for database operations.	General-purpose text type.
Best choice for record references.	Best choice for names, emails, and descriptions.

15-Character vs 18-Character Id

15-Character Id	18-Character Id
Case-sensitive	Case-insensitive
Mostly seen in the Salesforce UI	Commonly used by APIs and integrations
Less suitable for external systems	Preferred when exchanging data externally

How Salesforce Generates Record Ids

Insert Record

        │
        ▼

Salesforce Generates

Unique Record Id

        │
        ▼

Stores Record

        │
        ▼

Id Returned to Apex

        │
        ▼

Available for Queries & Updates

🔍 Behind the Scenes

New Account Created
        │
        ▼
Unique Id Generated
        │
        ▼
Database Record Stored
        │
        ▼
Id Assigned to Object
        │
        ▼
Available Throughout Transaction

✅ Best Practices

Use the Id data type instead of String when storing Salesforce record identifiers.
Use descriptive names such as accountId, contactId, or opportunityId.
Pass Id values directly into SOQL queries using bind variables.
Use the 18-character Id for integrations and external systems.

⚠️ Common Mistakes

Using String instead of Id for record identifiers.
Hardcoding record Ids in production code.
Confusing 15-character and 18-character Id formats.
Assuming two records can share the same Id.

🎯 Interview Tip

Question: Why should you use the Id data type instead of String for Salesforce record identifiers?

Answer: The Id data type is specifically designed for Salesforce record identifiers. It provides type safety, allows Salesforce to validate the identifier automatically, and makes Apex code clearer and easier to maintain than using a general-purpose String.

📌 Quick Revision

✔ Every Salesforce record has a unique Id.
✔ Use the Id data type instead of String for record identifiers.
✔ Salesforce supports both 15-character and 18-character Id formats.
✔ The 18-character format is preferred for integrations.
✔ Record Ids are commonly used in SOQL, DML, Apex, Flows, LWC, and integrations.
✔ Salesforce automatically generates a unique Id when a record is inserted.

➡ Next Lesson

In the next lesson, you'll explore the Blob data type, learn how Apex stores binary data such as files and images, and understand common use cases involving file processing, attachments, and content management.

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