Several typical issues about ABAP

Question 1 : Lock Object and FM (function module)
What is the FM name generated when a locked object is activated?
Answer : Create a lock object in the ABAP dictionary before creating a lock object in the ABAP dictionary. Program Locks. When a lock object is created, the system automatically generates two FM pairs for Lock management. The FM used to set the lock is: enqueue _ <Lock Object Name>. It is used to generate a lock entry in the lock table ). If the lock fails, it will be reflected in return. The FM used to release the lock is: dequeue _ <Lock Object Name>. It is used to delete a lock entry from the lock table. In the ABAP program, you only need to use the "Call funcition..." statement to call them. These two locks are executed in a special working process of the SAP system and are specially used for Lock management. It runs on a separate server, which is used to maintain the central locak table of the entire SAP system ). There are two types of locks: Shared locks-read-only locks. When a user is reading data, other users are prevented from changing the data. Exclusive lock-write lock. When a user is modifying data, other users are prevented from changing the data. Question 2: In terms of update, FM updates are divided into V1 and V2. Which update type will be executed first? Which mode (asynchronous, synchronous, or local) is used for each type of execution? Answer : V1 has a higher priority than V2. Therefore, V1 has a higher priority than V2. The V1 execution mode can be asynchronous, synchronous, or local; V2 can only be asynchronous. Question 3: What are the two statements used for ABAP memory (ABAP memory) exchange between programs using ABAP memory for data exchange? Answer : Export to memory id <ID> is used to copy data to ABAP memory. Import from memory id <ID> is used to copy data from ABAP memory to a program. Data exchanged between ABAP memory must be declared in both programs and contain the same data declaration.

Question 4: Authorization object)
What is an authorization object? Which statement is used in the ABAP program for authorization check?
Answer:An authorization object consists of a group of fields whose values are used for authorization checks. In the ABAP program, use the authority-check statement to perform authorization checks based on the authorization object.In authority-

In the check statement, all fields of the authorization object must be specified, but with one exception, you can use the dummy keyword to bypass the check of a field.
A maximum of 10 fields can be defined in an authorization object.

Question 5: Modify)
In the SAP system, how does one define "modification? What are their impacts on the update?
Answer: Modification refers to changes made to the repository object released by SAP.
Modifications must be reviewed during the update period to determine whether new SAP objects should be used and whether further modification is required for future use.

Question 6: Modify Assistant)
What is a change assistant?
Answer: Modify assistant is a tool introduced in version 4.5 to simplify the update process. You can use the ABAP editor to trigger the modification Assistant, which records the modifications made to the system. The modification Assistant supports modification through the ABAP Editor, screen painter, menu painter, text element maintenance, function builder, and ABAP dictionary.
Question 7: function module exit)
Which statement should be used in the SAP application when the function module exit is implemented?
Answer: Some SAP applications have function module exits, which allow users to add some features to the SAP program. You can search for "Call customer" to find whether a function module exit exists.

Question 8: Transaction variants)
What is a transaction variant? Why use it?
Answer: A transaction variant is a set of screen variants used to predefine screen behavior and default values. By using the variant function, you can remove unnecessary fields, sub-screens, and full screens from the user view. You can set the default value for any input field without the "ready for input" status.
Only transaction variants can be created for dialogs and report transactions. Only normal screens, subscreens, and dialog screens can be created.
Developers can use the guixt script language to modify the screen through transaction variant maintenance. You can modify the screen layout by inserting buttons, value helps, moving objects, and inserting screens.

Question 9: Change SAP)
List different methods for users to modify SAP standard functions.
Answer: SAP standard can be implemented through personalization, customizing,

Modify the modifications, enhancements, and the custom ABAP program. Examples of these methods are as follows:
Personalization-personalization technology includes creating variants, setting/obtaining parameters, and activity groups ).
Customizing -- is the most commonly used SAP tool (such as R/3 Reference Model and Implementation Guide) to change the SAP standard. It can be considered that mizmizing is necessary to implement R/3, which is usually executed by the functional team.
Enhancements is usually executed by the development team. The activities include dictionary enhancement, funciton module exits, menu and screen exit, and business add-ins (Badi ).

Custom ABAP program-it can work with SAP objects or custom development objects.
Modifications -- modifications are not recommended for SAP objects. Use sscr (SAP software change registry) to register all manual modifications to sap objects.

Question 10: Add a field
Which two methods are used to add fields to an SAP table?
Answer: The two methods are: append structure and custom include ). The append structure is created when a field is added to the end of the table. The custom include structure is specified by SAP developers so that users can create new fields.

Question 11: What is Badi?
answer : Badi is short for business add-in. It is a new function enhancement concept, using ABAP object technology. This is an object-oriented method for SAP enhancement. Class, interface, and method object-oriented concepts are used to implement Badi.
to enhance an SAP application, you must first define Badi. Create an interface for Badi, create an adapter class to implement this interface, and then create an instance of this adapter class.