---
manual: IM 36K10P30-01EN
title: Data Set Service Language
edition: 3rd Edition, Sep. 2023
version: R1.03
status: compiler run as a syntax check on a copy of the installed DSS files and on a deliberately broken test file (2026-10-01); defining new datasets and updating the dictionary from docs only
---

# Data Set Service Language (R1.03)

The DSS language describes datasets; the DSS compiler (`dss.exe`) checks the descriptions and
builds the data dictionary (`%TLS_DAT_PATH%\tlsdic_dss.dic`) and C include files. It is a system
integrator's tool: **changing the dictionary changes CI Server itself** and is only needed for
custom datasets, custom report destinations (`IM36K10R40-01EN.md` §3.3) or custom data access
servers. Section numbers refer to the manual.

## 1. DSS files (§2)

- Plain text, one dataset per file recommended, extension `.dss`. The installed descriptions are
  in `%TLS_ROOT_PATH%\tls\src\` (253 `.dss` files on the test system, plus `.c` sources of the
  data access servers and `.umh` message files). Reading them is the best way to learn a
  dataset's fields, ranges, lists and defaults (`dssqld -f` shows the same information).
- Syntax: `<KEYWORD value>` or `<KEYWORD <SUB …> …>`; keywords case-insensitive; strings in
  double quotes with `""` for a quote; `/* */` and `//` comments.
- Order in a file: includes (`<INCLUDE "dss_global.dss">`), constants
  (`<DEFINE_CONSTANT <LABEL …> <VALUE …>>`), macros, field templates, storage nodes, then
  `<DATASET <NAME …> <DESCRIPTION …> <FIELD …>… <PHYSICAL_FIELD …>… <INDEX …>… <DATA_FILE …>
  <DATA_ACCESS <SERVERNAME "dsilib:…">> <OPERATIONS> <STORAGE <NODES …>> …>`.
- A dataset needs a name (not an SQL keyword, unique), at least one field and one unique index.
- Texts (descriptions, headings, list entries) can carry translations (English, Dutch, German,
  French).
- Field properties: data type or field template, description, heading, format, transformation,
  basic operations, range/step, list (`<ENTRY <NUMERIC n> <STRING "text">>`), required, hidden,
  concealed, default, character restrictions/operations, password-encrypted, "maps upon"
  (relational field to another dataset), enabled, validate, group. Relational and compound
  (composed) fields and physical fields have their own sentences; indexes may be unique.

## 2. Compiler (§3)

Run `dss` in the folder that holds the `.dss` files; it compiles **all** of them.

| Flag | Effect |
|---|---|
| none | Syntax check only (errors on screen) |
| `-d[<dict>]` | Create/update a dictionary (default `tlsdic_dss.dic` in `%TLS_DAT_PATH%`) — host node only; other nodes get the change through `DSSWTH` |
| `-i` | Write C include files (`.dsh`) |
| `-l[<list>]` | List file (default `tlsdic_dss.lst` next to the files) |
| `-q` / `-w` / `-b` | Quiet / no warnings / no boundary check |

**Installed (verified):** a copy of the 253 installed files compiled in 2 s with no errors
(`dss -l -w`, 251 files plus the two include files) and `tlsdic_dss.dic` was not touched. A test
file with a missing `>` gave `cieng_test_df.dss (15,2): EOF is not expected, expected 1
end-of-sentence characters ('>')` and `1 errors found.` The start script uses an undocumented
`-u` (compile without the DSS shared memory) on the first start. `dssxdb` has a "beautify DSS
dictionary source" function to find unbalanced `<` `>` (`IM36K10L50-01EN.md` §1.2).

To add a value to an existing list (e.g. a report destination, R40 §3.3): edit the `.dss` in
`tls\src`, run `dss -d` in that folder, restart CI Server. Not practiced (would change the test
system's dictionary).

## 3. Include files (§4)

The `.dsh` output holds constants, dataset information, a C record structure and index
information for programs that use the DSS API. Not needed for engineering work.