Tolong jelaskan mengenai Defining data objects dari ABAP dalam bahasa melayu

There are various statements that you can use to define data objects.

The TABLES statement always refers to the global type of a flat structure that is defined in the ABAP Dictionary. The structure type for the data object in the program is taken from the Dictionary. The data object name is identical to the name of the structure type. They are normally used as an interface to the screen.

The DATA statement is usually used to define local data objects. The data object type is specified using the TYPE addition.

The PARAMETERS statement defines not only an elementary data object, but also an input field on the standard selection screen that is processed at the start of the program.

When you activate a program, an internal load version is generated. A selection screen is generated from the PARAMETERS statement. When the program starts, memory areas are made available for the data objects.

You can find further information on data objects in the unit entitled ABAP Statements and Data Declarations, or in the keyword documentation.

The SELECT statement ensures that data is read from the database. In order to read a record from a database table, the following information must be passed to the database:

From which database table is the data read? (FROM clause)

How many lines are read? The SINGLE addition shows that only one line is read.

Which line is read? The WHERE clause shows which columns of the database table have which values.

For a SELECT SINGLE, the condition must be formulated so that one line is specified unambiguously.

Dialog programs are used for both reading from and writing to the database.