Introduction to SAP ABAP Dictionary (SE11)

The ABAP Dictionary (often called the Data Dictionary) is the central repository in SAP for defining and managing database objects, structures, and data types.

In a large enterprise handling thousands of employee records, sales orders, and material prices, you need a system to decide how data is structured, where it is stored, and what validation rules apply. This is exactly what the ABAP Dictionary manages.

Every table, field name, and data type that exists anywhere in the SAP system is defined here.

ℹ️ Note: Access and maintain ABAP Dictionary objects using transaction code SE11.

---

How to Open SE11

1. Login to your SAP GUI account with your username and password.
2. Find the command field in the top-left corner of the SAP screen.
3. Type SE11 and press Enter.
4. The initial ABAP Dictionary screen will display several options:

• Database Table
• View
• Data Type
• Type Group
• Domain
• Search Help
• Lock Object

---

Database Tables

A database table stores data in the form of rows (records) and columns (fields). When an organization stores employee information or records a sales order, the data is ultimately stored in database tables.

Types of Tables in SAP

There are three primary types of database tables:

1. Transparent Table:

• There is a 1:1 relationship between the table definition in the ABAP Dictionary and the physical table structure in the database.
• It stores user/application data.

2. Pooled Table:

• There is a Many-to-One (N:1) relationship between the ABAP Dictionary and the physical database tables.
• Multiple pooled tables are consolidated into a single table pool in the database.
• A primary-foreign key relationship is not required for pooled tables.

3. Cluster Table:

• There is a Many-to-One (N:1) relationship between the ABAP Dictionary and the database table cluster.
• It is designed to store continuous streams of data (e.g., system logs or financial document segments).
• Primary-foreign key relationships are required.

---

What’s Inside a Table? — Fields Tab Explained

When you open any database table in SE11 and click the Fields tab, you see a list of columns. Here is what each setting means:

Column	What It Means
Field Name	The actual technical name of the field.
Key	Checked if this field is part of primary key (unique identifier for each row).
Data Element	The reusable definition that describes this field’s business type and labels.
Data Type	The technical data type — CHAR (text), NUMC (numbers), DATS (date), etc.
Length	Maximum number of characters/bytes allowed in this field.
Short Description	A plain English label explaining the field’s purpose.

---

What is a Domain?

A Domain describes the technical attributes of a field, such as its data type and length.

• Examples: NUMC(10), CHAR(40).
• Domains are not linked directly to table fields; instead, they are assigned to Data Elements, which are then used in the table fields.

---

What is a Data Element?

A Data Element describes the semantic properties or appearance of a field to the end user. It provides a meaningful description (field labels) to a technical field, making it readable on front-end screens and report column headings.

---

Primary Key / Foreign Key Relationship

A Foreign Key links tables together by establishing a parent-child relationship.

• The Primary Key of a parent table acts as a Foreign Key in the child table.
• For the relationship to exist, both tables must share at least one common attribute (column).
• Cardinality defines the number of corresponding records between the tables for a particular entry (e.g., 1:1, 1:N).