extract s/m

[Former Member]

Hi,

What does an extract statement do in the ABAP program?

Rai...

[Former Member]

Hi,

What does an extract statement do in the ABAP program?

Rai...

[Former Member]

EXTRACT header | field_group .

Effect

This statement links the current content of the fields, which were until then included in the field group header resp. field_group via the statement INSERT , to the extract dataset of the program. If there is no field group specified after EXTRACT, then the field group header is implicitly added.

At the first execution of the EXTRACT-statement of a program, the extract dataset is created and the first line added. After execution of an EXTRACT-statement, it is not allowed to incorporate other fields to the specified field group field_group with the INSERT statement. If you do so, an uncatchable exception will be raised at the next EXTRACT-statement for the same field group.

Notes

As the field group header is the beginning part and sort key of every field group, it is not allowed to incorporate fields into header after execution of the first EXTRACT statement.

The lines of an extract dataset cannot be explicitly deleted and will be kept alive as long as the internal mode of the program.

Example

This example continues the example under INSERT. If the executable program is linked to a fitting logical data base, the fields of the field groups flight_info and flight_date are attached to the extract dataset during the GET-events.

REPORT demo_extract.

NODES: spfli, sflight.

FIELD-GROUPS: header, flight_info, flight_date.

START-OF-SELECTION.

INSERT: spfli-carrid spfli-connid sflight-fldate

INTO header,

spfli-cityfrom spfli-cityto

INTO flight_info.

GET spfli.

EXTRACT flight_info.

GET sflight.

EXTRACT flight_date.

[Former Member]

Hi Rai,

Once you have declared the possible record types as field groups and defined their structure, you can fill the extract dataset using the following statements:

EXTRACT <fg>.

When the first EXTRACT statement occurs in a program, the system creates the extract dataset and adds the first extract record to it. In each subsequent EXTRACT statement, the new extract record is added to the dataset

EXTRACT HEADER.

When you extract the data, the record is filled with the current values of the corresponding fields.

As soon as the system has processed the first EXTRACT statement for a field group <fg>, the structure of the corresponding extract record in the extract dataset is fixed. You can no longer insert new fields into the field groups <fg> and HEADER. If you try to modify one of the field groups afterwards and use it in another EXTRACT statement, a runtime error occurs.

By processing EXTRACT statements several times using different field groups, you fill the extract dataset with records of different length and structure. Since you can modify field groups dynamically up to their first usage in an EXTRACT statement, extract datasets provide the advantage that you need not determine the structure at the beginning of the program.

Kind Regards

Yogesh Gupta

[Former Member]

Hi,

Once you have declared the possible record types as field groups and defined their structure, you can fill the extract dataset using the following statements:

EXTRACT <fg>.

When the first EXTRACT statement occurs in a program, the system creates the extract dataset and adds the first extract record to it. In each subsequent EXTRACT statement, the new extract record is added to the dataset.

Each extract record contains exactly those fields that are contained in the field group <fg>, plus the fields of the field group HEADER (if one exists). The fields from HEADER occur as a sort key at the beginning of the record. If you do not explicitly specify a field group <fg>, the

EXTRACT

statement is a shortened form of the statement

EXTRACT HEADER.

When you extract the data, the record is filled with the current values of the corresponding fields.

As soon as the system has processed the first EXTRACT statement for a field group <fg>, the structure of the corresponding extract record in the extract dataset is fixed. You can no longer insert new fields into the field groups <fg> and HEADER. If you try to modify one of the field groups afterwards and use it in another EXTRACT statement, a runtime error occurs.

By processing EXTRACT statements several times using different field groups, you fill the extract dataset with records of different length and structure. Since you can modify field groups dynamically up to their first usage in an EXTRACT statement, extract datasets provide the advantage that you need not determine the structure at the beginning of the program.

Assume the following program is linked to the logical database F1S.

REPORT demo_extract_extract.

NODES: spfli, sflight.

FIELD-GROUPS: header, flight_info, flight_date.

INSERT: spfli-carrid spfli-connid sflight-fldate

INTO header,

spfli-cityfrom spfli-cityto

INTO flight_info.

START-OF-SELECTION.

GET spfli.

EXTRACT flight_info.

GET sflight.

EXTRACT flight_date.

There are three field groups. The INSERT statement assigns fields to two of the field groups. During the GET events, the system fills the extract dataset with two different record types. The records of the field group FLIGHT_INFO consist of five fields: SPFLI-CARRID, SPFLI-CONNID, SFLIGHT-FLDATE, SPFLI-CITYFROM, and SPFLI-CITYTO. The first three fields belong to the prefixed field group HEADER. The records of the field group FLIGHT_DATE consist only of the three fields of field group HEADER

with regards,

sowjanyagosala