SAP Explained: Data Class vs. Delivery Class Demystified

When you're creating a new database table in the SAP ABAP Dictionary (Transaction SE11), you'll encounter a crucial tab: "Delivery and Maintenance". Here, two fundamental settings, Data Class and Delivery Class, dictate the future behavior and performance of your table. While they might seem similar, they serve entirely different purposes. Getting them wrong can lead to performance bottlenecks and transport headaches down the line.

Let's break down each one to understand their distinct roles.

What is Data Class? The 'Where' of Your Data

The Data Class is a technical setting that determines the physical area (known as a "tablespace" or "dbspace" in the database) where your table's data will be stored. Think of it as assigning your table to a specific neighborhood in the database city. This is primarily for performance optimization and database administration.

By grouping tables with similar characteristics—like how often they are accessed or how large they are—database administrators can optimize storage and access speeds. For instance, master data, which is read frequently but changed rarely, can be stored in a different, highly-optimized tablespace than transaction data, which is written constantly.

Common Data Classes:

• APPL0: Master Data. This is for data that is frequently read but rarely updated (e.g., customer master, material master).
• APPL1: Transaction Data. This is for data that changes frequently (e.g., sales orders, financial postings).
• APPL2: Organizational and Customizing Data. This is configuration data that is set up once and rarely changes.
• USER, USER1, USER2, USER3: Reserved for customer data. It is standard practice to use these for your custom Z-tables.

Choosing the correct Data Class helps the database manage memory and storage efficiently.

// In SE11 -> Technical Settings

Data Class: APPL0 (For a custom employee master table)

What is Delivery Class? The 'How' of Data Transport

The Delivery Class, on the other hand, controls the logistics of the table's data. It defines how the data within the table is handled during system installations, upgrades, client copies, and transports between different SAP systems (e.g., from Development to QA to Production).

This setting is crucial for determining whether the data in your table is considered application data (like a sales order) or customizing data (like a new sales organization) that needs to be moved across the landscape.

Common Delivery Classes:

• A: Application table. Data for this table is considered master or transaction data. It is not transported with customizing requests. You would typically use BAPIs, IDocs, or specific data migration tools to move this data.
• C: Customizing table. The data in this table is transported along with customizing requests. Users can maintain the data in the production system. This is the most common class for custom configuration tables.
• L: Table for storing temporary data. The data is not transported and is for temporary storage only.
• G: Customizing table, but protected against SAP Upgrades. SAP cannot deliver new data records for this table.
• E: Control table. SAP and customers can deliver data in specified key ranges.
• S: System table. Maintained only by SAP.
• W: System table. Its contents can be transported via specific transport objects.

// In SE11 -> Delivery and Maintenance tab

Delivery Class: C (For a custom configuration table that needs transport)

Key Differences at a Glance

Let's summarize the core differences in a simple table:

Aspect	Data Class	Delivery Class
Purpose	Physical storage in the database (Tablespace).	Data transport and maintenance behavior.
Impacts	System performance, database administration.	Data transport, client copy, system upgrades.
Concerns	The 'Where' (Where is the data physically stored?)	The 'How' (How is the data moved/maintained?)
Example Choice	APPL0 for master data.	A for master data, C for customizing data.

Conclusion

In short: Data Class is for the database, Delivery Class is for the SAP system landscape.

• Choose the Data Class based on the type of data and its expected access patterns to ensure optimal performance.
• Choose the Delivery Class based on how you want the table's data to behave during transports and maintenance across your Development, QA, and Production systems.

Understanding this distinction is a hallmark of a proficient SAP developer or consultant. Selecting the correct classes from the beginning ensures a robust, performant, and maintainable application.