SAP ALE Tutorial
ALE stands for Application Link Enabling.ALE is used for exchanging business data between different systems.This form of communication requires IDOC interface.The IDoc interface is made up of the definition of a data structure and the processing logic of this data structure. The data structure is the IDoc. The IDoc is the general exchange format of the communicating systems.ALE supports the configuration and operation of distributed applications. It allows the controlled exchange of business messages between distributed applications with consistent data retention. The coupling between the distributed systems can be either narrow or loose.The application integration is not achieved through a centralized database. Instead, the applications access a local database. Data retention is redundant. ALE ensures the distribution and synchronization of master, control, and transaction data through asynchronous communications. ALE uses synchronous connections to read data.
ALE, EDI & IDocs Introducion & Difference: SAP Tutorial.
EDI Architecture
EDI Architecture consists of –

EDI-enabled applications :They support the automatic processing of business transactions.
The IDoc interface: This was designed as an open interface. The IDoc interface consists of IDoc types and function modules that form the interface to the application.
The EDI subsystem: This converts the IDoc types into EDI message types and vice versa. This component of the EDI architecture is not supplied by SAP.
Advantages of EDI process
Reduced data Entry Errors
Reduced Processing cycle time
Availability of data electronic form
Reduced Paper Work
Reduced Cost
Reduced Inventories and Better Planning
Standard Means of Communicating
Better Business Processes
Competitive Advantage
What is ALE ?
ALE supports the distribution of the business functions and process across loosely coupled SAP R/3 systems (different versions of SAP R/3). Connections from R/2 and non SAP systems is also supported.
ALE supports-

Distribution of applications between different releases of R/3 Systems
Continued data exchange after a release upgrade without requiring special maintenance
Customer-specific extensions.
Communication interfaces that allow connections to non-SAP systems.
Coupling of R/3 and R/2 Systems.
Difference between ALE and EDI ?
ALE is used to support distributed yet integrated processes across several SAP systems whereas EDI is used for the exchange of business documents between the systems of business partners (could be non-SAP systems)
ALE is SAP’s technology for supporting a distributed environment whereas EDI is a process used for exchange of business documents which now have been given a standard format

Both ALE and EDI require data exchange. An Idoc is a data container which is used for data exchange by both EDI and ALE processes.

What is IDOC?
IDOC is simply a data container used to exchange information between any two processes that can understand the syntax and semantics of the data.
In simple words , an idoc is like a data file with a specified format which is exchanged between 2 systems which know how to interpret that data.

IDOC stands for ” Intermediate Document”

When we execute an outbound ALE or EDI Process, an IDOC is created.In an inbound ALE or EDI process, an IDOC serves as input to create an application document.In the SAP System, IDOCs are stored in database.Every IDOC has an unique number(within a client).

IDOCs are based on EDI standards, ANSI ASC X12 and EDIFACT. In case of any conflict in data size, it adopts one with greater length. IDOCs are independent of the direction of data exchange e.g. ORDERS01 : Purchasing module : Inbound and Outbound.IDOCs can be viewed in a text editor. Data is stored in character format instead of binary format.IDOCs are independent of the sending and receiving systems.(SAP-to-SAP as well as Non-SAP).
SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables.
What is an IDOC?
IDOC is simply a data container used to exchange information between any two processes that can understand the syntax and semantics of the data.

In other words, an IDOC is like a data file with a specified format which is exchanged between 2 systems which know how to interpret that data.

IDOC stands for ” Intermediate Document”

When we execute an outbound ALE or EDI Process, an IDOC is created.

In the SAP System, I DOCs are stored in database. Every IDOC has a unique number(within a client).

In this tutorial you will learn:

What is an IDOC?

Structure of an IDOC

IDOC Types

What is a Segment?

What is Extension IDOC type?

IDOC Views

Partner Profiles

Port

The Outbound Process

The Inbound Process

Key Features
IDOCs are independent of the sending and receiving systems.(SAP-to-SAP as well as Non-SAP)
IDOCs are based on EDI standards, ANSI ASC X12 and EDIFACT. In a case of any conflict in data size, it adopts one with greater length.
IDOCs are independent of the direction of data exchange e.g. ORDERS01: Purchasing module: Inbound and Outbound
IDOCs can be viewed in a text editor. Data is stored in character format instead of binary format.
Structure of an IDOC
SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

The I doc structure consists of 3 parts –

The administration part(Control Record)- which has the type of idoc, message type, the current status, the sender, receiver etc. This is referred to as the Control record.
The application data (Data Record) – Which contains the data. These are called the data records/segments.
The Status information (Status Record)- These give you information about the various stages the idoc has passed through.
You can view an I-DOC using transaction WE02 or WE05

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

As seen the screenshot above IDOC record has three parts Control, Data and Status. Let’s look into them in detail – Control Record

All control record data is stored in EDIDC table. The key to this table is the IDOC Number
It contains information like IDOC number, the direction(inbound/outbound), sender, recipient information, channel it is using, which port it is using etc.
Direction ‘1’ indicates outbound, ‘2’ indicates inbound.
Data Record

Data record contains application data like employee header info, weekly details, client details etc
All data record data is stored in EDID2 to EDID4 tables and EDIDD is a structure where you can see its components.
It contains data like the idoc number, name and number of the segment in the idoc, the hierarchy and the data
The actual data is stored as a string in a field called SDATA, which is a 1000 char long field.
Status Record

Status record is attached to an I-DOC at every milestone or when it encounter errors.
All status record data is stored in EDIDS table.
Statuses 1-42 are for outbound while 50-75 for inbound
IDOC Types
An I DOC Type, (Basic) defines the structure and format of the business document that is to be exchanged. An IDOC is an instance of an IDOC Type , just like the concept of variables and variables types in programming languages. You can define IDOC types using WE30

What is a Segment?
A Segment defines the format and structure of a data record in I-DOC. Segments are reusable components.

For each segment SAP creates.
Segment Type (version independent)
Segment Definition (version dependent)
Segment Documentation
The last 3 characters is the version of the segment

Definitions keep changing as per the version but the segment type remains the same.

Transaction:WE31

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

What is Extension IDOC type?
An IDOC is of 2 types:-

Basic
Extension
SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

SAP provides many a pre-defined Basic IDOC Types which can not be modified. In case you want to add more data to these restricted basic type you may use an extension type. Most of the times you will NOT use extension.

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

Documentation
Each IDOC are thoroughly documented in transaction WE60

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

Message Type
A message represents a specific type of document that is transmitted between two partners Ex. Orders, orders responses, invoices etc

An idoc type can be associated with many message types

Also, a message type can be associated with different idoc types. Transaction WE81

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

IDOC Views
An IDOC type can be used for more than one message type, which results in IDOCs containing more fields than required for a particular message type.
IDOC views are used to improve performance in generating IDOCs to ensure only the relevant segments are filled with data. IDOC Views are important only for Outbound Processing.

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

Partner Profiles
A partner is defined as a business partner with whom you conduct business and exchange documents

In the partner profile of a partner that we exchange Idocs with, we maintain the parameters that are necessary for exchanging the data. The transaction used is WE20.

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

Port
The port defines the technical characteristics of the connection between your SAP system and the other system you want to transfer data with (subsystem). The port defines the medium in which data is exchanged between the 2 systems.

There are different types of ports. The 2 most commonly used are the TRFC ports used in ALE and File ports which EDI uses.

For TRFC ports we have to give the name of the logical destination created using SM59.

When using file port you can specify the directory where the IDOC file should be placed. The other system or the middleware will pick up the file from here. The Function module can be used to generate a file name for the idoc. While Testing you can use “Outbound file” to specify a constant file name. The tab “outbound trigger” can be used to supply information if we want to trigger some processing on the subsystem when an idoc is created at this location. We have to specify the command file name and the directory which has to be run.

SAP IDOC Tutorial: Definition, Structure, Types, Format & Tables

This is so CONFUSING!
Let’s understand the process of creating an IDOC with an example –

Whenever a Purchase Order (PO) is created we want to send the IDOC to a vendor.
The PO is sent in the form of an IDOC to the vendor (partner). That partner has to be EDI enabled in that system. SAP should realize that it could send doc to this vendor electronically.
The PO sent as an outbound idoc by the customer will be inbound idoc for the vendor. The SAP system on the vendor’s side can process this to create an application document (a sales order) on their system.
Quotation, RFQ, PO, SO, Invoice, delivery note etc are some of the commonly exchanged documents through IDOC
The process of data transfer out of your SAP system is called the Outbound process, while that of data moving into you SAP system is called Inbound process. As a developer or a consultant who will be involved in setting up theses process for your organization. Here are the steps how to set them up-

The Outbound Process
Steps Involved –

Create segments(WE31)
Create an idoc type(WE30)
Create a message type (WE81)
Associate a message type to idoc type(WE82)
Create a port(WE21)
If you are going to use the message control method to trigger idocs then create the function module for creating the idoc and associate the function module to an outbound process code
Otherwise, create the function module or stand-alone program which will create the idoc
Create a partner profile(WE20) with the necessary information in the outbound parameters for the partner you want to exchange the idoc with.Trigger the idoc.
The Inbound Process
Steps Involved-

Creation of basic Idoc type (Transaction WE30)
Creating message type (Transaction WE81)
Associating the Message type to basic Idoc type (Transaction WE82)
Create the function module for processing the idoc
Define the function module characteristics (BD51)
Allocate the inbound function module to the message type(WE57)
Defining process code (Transaction WE42)
Creation of partner profile (Transaction WE20)