SAP ABAP Program to insert data into custom table zstudent from selection screen

 Program: 

REPORT zinsert_student.

TABLES: zstudent.

* Selection screen fields

PARAMETERS: 

  p_id     TYPE zstudent-student_id,

  p_name   TYPE zstudent-name,

  p_age    TYPE zstudent-age,

  p_course TYPE zstudent-course.

START-OF-SELECTION.

  DATA: lv_exists TYPE c.

* Check if student already exists

  SELECT SINGLE student_id 

    INTO @DATA(lv_student_id) 

    FROM zstudent 

    WHERE student_id = @p_id.

  IF sy-subrc = 0.

    MESSAGE 'Student ID already exists!' TYPE 'E'.

  ENDIF.

* Insert record

  INSERT INTO zstudent VALUES (

    p_id

    p_name

    p_age

    p_course

  ).

  IF sy-subrc = 0.

    MESSAGE 'Student inserted successfully!' TYPE 'S'.

  ELSE.

    MESSAGE 'Insert failed!' TYPE 'E'.

  ENDIF.