
Data Segments
Definition
DART extracts are organized in segments. A data segment stores a collection of fields from R/3 tables. A data segment may hold master data, or data from an application document. A segment is a collection of all the records of the same type. A segment may contain data from a single R/3 database table, or it may combine related data from multiple tables.
The following diagram illustrates the arrangement of segments in the data extract.

Use
DART supplies a large set of predefined segments. These include multiple segments for many of the major R/3 application areas.
The technical names of all SAP-provided data segments start with TXW_. For example, one of the segments, namely TXW_MM_POH, contains Purchase Order document header data. Another segment, TXW_MM_POP, contains Purchase Order line item data.
If you wish to configure DART to extract data from additional tables or fields, that is, from tables or fields not included in the SAP-provided set of segments, then you need to add segments or expand the existing segments. You may need to create a customer enhancement to handle this data. See the topic of
Integration
A data segment in DART must be based on an existing structure in the ABAP Data Dictionary. The data segment in DART uses the same name as the structure in the Data Dictionary, and it also contains the same fields as the structure.
A data segment may contain a mixture of fields from multiple R/3 tables.
The following illustration shows how the fields in a DART segment correspond to a structure in the Data Dictionary, which, in turn, corresponds to fields in tables in the database

For the SAP-provided data segments, the corresponding Data Dictionary structures have already been defined. They use the same name as their corresponding data segment.
You must create the necessary Data Dictionary structures for every segment you create, as part of the process of
adding new segments or adding fields to existing segments.Structure
A segment definition contains the fields to be extracted and the tables from which to extract these fields.
A segment definition also specifies other attributes of the segment, such as indexes on one or more of its fields.
Defining indexes on fields in a segment can enhance the performance of
data extract views.The SAP-provided data segments have predefined index fields to enhance the performance of the SAP-provided data views. You may add or change the index fields on these predefined data segments in the same way that you can define indexes for data segments you create.
You may designate one of the fields in a segment as the key figure field for
control totals. DART then adds all the values in such a field for the whole segment by company code and by period if available. You can use these sums to verify the integrity of the data in an extract.DART provides a predefined control totals key figure for the FI documents line item segment: it adds all the amounts in the local currency amount field for this segment. DART also provides a report to compare the sums of this key figure in the extract file with the current amount in the database. You can use this report, for example, to see if any FI documents have been posted since the data has been extracted. This can help you verify the integrity of the data in the extracted file, because for a certain period, after it has been closed, there should not be any postings that have not been retained in the extract file.
You may also designate one of the fields in a segment as the grouping field for
control totals. DART calculates separate control totals for each possible grouping field value. For example, for the FI document line item segment, the grouping field is the Debit/Credit indicator field. That means that when calculating control data sums for the segment, the system calculates a separate sum for debit and credit values respectively.See Also
Customer Enhancements: Adding Segments and Fields, Creating a New Segment and Defining Its Attributes, Changing the Attributes of an SAP-Provided Segment, Listing Segment Information, Control Totals, Data File Views