What is the DMD file format?
A .dmd file is the top-level anchor document created by Oracle SQL Developer Data Modeler, Oracle's free visual database design tool. It is a small XML file - rooted at <OSDM_Design> - that stores the metadata for a complete database design: the design name, creator information and structural pointers to the rest of the model.
A .dmd file is never self-contained. It sits at the root of a design folder hierarchy and references subdirectories - typically logical/, rel/, datatypes/ and subviews/ - each holding their own XML files with the actual model content: entity-relationship diagrams, physical relational models, data type definitions and subview layouts. Moving or sharing a design requires copying both the .dmd file and its entire accompanying folder tree.
The file begins with <?xml version='1.0' encoding='UTF-8'?> followed by the <OSDM_Design> root element. The format is tied to the Data Modeler release that wrote it; opening a newer design in an older version may fail.
Oracle SQL Developer Data Modeler supports forward engineering (generating DDL SQL from the model) and reverse engineering (importing an existing database schema). The tool is cross-platform, Java-based and available free from Oracle.
Security & safety
RISK: LOWDMD files are XML text describing database schemas - they contain no executable code and pose no direct security risk. The XML may reference proprietary class names specific to Oracle's toolchain, but these are data declarations, not code. Standard XML-handling cautions apply (do not parse untrusted XML in schema-validating contexts without limits).
Format details
in a nutshell- Visual dBASE Data Module - Legacy Visual dBASE (Borland/Inprise, 1990s) used .dmd for data module files - a 16-bit/Windows-era database IDE component; completely discontinued, Windows 3.x/9x era.
- D language module cache / Digital Mars D compiler artefact - The DMD compiler for the D programming language produces .dmd files as build artefacts in some toolchain versions; these are binary compiler caches, unrelated to database modelling.
Programs that open DMD files
Windows1 app
Oracle SQL Developer Data Modeler
Free File > Open (or Open Design) - browse to the .dmd file. Make sure the design subfolder is in the same directory. 
macOS1 app
Oracle SQL Developer Data Modeler
Free File > Open - select the .dmd. Requires Java; the tool is cross-platform. 
Linux1 app
Oracle SQL Developer Data Modeler
Free Run the Data Modeler on Linux (Java); File > Open the .dmd with its subfolder present. Technical details
deep spec| File format | XML document; begins with <?xml version='1.0' encoding='UTF-8'?> |
| Root element | <OSDM_Design class="oracle.dbtools.crest.model.design.Design"> |
| MIME type | application/xml |
| File encoding | UTF-8, declared in the XML prolog |
| Standalone | No - the .dmd is an anchor file; full design data lives in an accompanying subdirectory tree |
| Design subdirectories | logical/, rel/, datatypes/, subviews/, pm/ - each holding XML model content files |
| Typical file size | 1 KB - 100 KB (descriptor only; bulk model content is stored in subdirectories) |
| Version compatibility | File format tied to the Data Modeler release that wrote it; newer files may not open in older tool versions |
| Platform | Cross-platform; Java-based tool runs on Windows, macOS and Linux |
| Supported model layers | Logical (ERD), relational, physical, data type, process model and business information layers |
| Engineering support | Forward engineering to DDL SQL; reverse engineering from existing database schemas |
| Proprietary schema | Oracle-proprietary internal format (oracle.dbtools.crest.*); no published open XML schema |
| Tool availability | Oracle SQL Developer Data Modeler is free to download from Oracle |
| Released | Oracle SQL Developer Data Modeler 1.0 (circa 2007-2008) |
| Latest version | Oracle SQL Developer Data Modeler 23.1+ (2023 onwards) |
| Specification | docs.oracle.com |
DMD conversions
Community Q&A
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