What is parameter id and default component in data element? Help!

Question

Hi experts,
      In the further characteristics, What is parameter id and default component name in data element? what are they used for?
Example: S_CARR_ID.
Thanks
Gopal

Answer 1

Hi,
Parameter ID :- Is used for assigning value to field.
Suppose u call a transaction in u porgram.
and u want to assign some value to field before executing the transaction.
if the field has parameter id u can assign value to field before calling the transaction.
that is it take the default value from the memmory.
and u set value in the memmory using parameter id.
<b>----
GET PARAMETER -
</b>
Basic form 3
GET PARAMETER ID pid FIELD f.
In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See ABAP Unicode - Other Changes
Effect
First, the value stored under the key pid is transferred from the local SAP memory into the field f. If this key is not available in the local SAP memory, the value stored under the same key pid is transferred from the global user-related SAP memory to the field f.
A parameter ID can have up to 20 characters. You can find an overview of the keys (parameters) used in the SAP system description or the appropriate function in the ABAP Workbench.
The Return Code is set as follows:
SY-SUBRC = 0: A value was read from SAP memory. SY-SUBRC = 4: No value was found in SAP memory under the specified key.
Notes
The global user-related SAP memory is available to each user for the entire duration of a terminal session. For this reason, set values are retained when you leave a program.
You should not use SAP memory for temporary storage because a user's parallel sessions use the same global memory.
Example
Read the program name from SAP memory:
DATA : REPID LIKE SY-REPID.
GET PARAMETER ID 'RID' FIELD REPID.
<b>----
SET PARAMETER -
</b>SET PARAMETER ID pid FIELD f.
In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See ABAP Unicode - Other Changes
Effect
Writes the contents of the field f to the global user-specific SAP memory and the local transaction-specific SAP memory under the ID pid. Any existing values under the same ID are overwritten.
Parameter IDs can be up to 20 characters long. They cannot consist entirely of spaces. The SAP system description contains an overview of parameter IDs. You can also produce a list using the ABAP Workbench.
Notes
The global, user-specific SAP memory is available to a user for the duration of a single terminal session. Values written to it are retained even when the user exits a program.
Do not use SAP memory as a temporary storage area, since parallel sessions belonging to the same user all use the same memory area.
Only store data of the types C, N, D, and T, as well as structures that consist of these types, in the SAP Memory.
You can create new parameter IDs using the ABAP Workbench.
Parameter IDs may have a namespace prefix.
Example
DATA REPID like sy-repid VALUE 'RSPFPAR'.
SET PARAMETER ID 'RID' FIELD REPID.
Message was edited by: Manoj Gupta