SDTM
Each domain dataset is distinguished by a unique, 2-character code that should be used consistently throughout the submission. This code, which is stored in the SDTM variable named DOMAIN, is used in 4 ways: as the dataset name, as the value of the DOMAIN variable in that dataset, as a prefix for most variable names in that dataset, and as a value in the RDOMAIN variable in relationship tables (see Section 8, Representing Relationships and Data).
All datasets are structured as flat files with rows representing observations and columns representing variables.
Each domain is represented by a single dataset.
SEND datasets are named to be consistent with the domain code (see the Study Data Technical Conformance Guide for more details on naming datasets for submission to the FDA; https://www.fda.gov/media/88173/download). For example, the Demographics (DM) dataset is named dm.xpt. See SEND controlled terminology (available at http://www.cdisc.org/terminology) for a list of standard and reserved domain codes. Exceptions to this rule are described in the following subsections for general-observation class datasets. See Section 8.2, Relating Records - RELREC, for RELREC; Section 8.3, Supplemental Qualifiers - SUPP-- Datasets, for SUPP; and Section 8.5, Relating Findings To Multiple Subjects - Subject Pooling, for POOLDEF.