How to Extract BLOB/CLOB Data from Oracle Dump Files
In Oracle databases, binary data like images, PDFs, and documents are stored as BLOB (Binary Large Object), while long text data is stored as CLOB (Character Large Object).
Extracting this LOB data from .dmp files was traditionally difficult, but OraDB DUMP Viewer makes it easy — no Oracle environment needed.
What is LOB Data?
| Type | Full Name | Use Cases | Max Size |
|---|---|---|---|
| BLOB | Binary Large Object | Images, PDFs, videos, ZIP files | 4GB |
| CLOB | Character Large Object | Long text, XML, JSON, HTML | 4GB |
Previewing LOB Data
In OraDB DUMP Viewer's data preview, LOB columns show their content:
- CLOB: Text content displayed directly
- BLOB: Data size shown, with thumbnail preview for images
Extracting LOB Data as Files
Single Table LOB Extraction
- Select a table containing LOB columns
- Choose the LOB Extract feature
- Specify an output folder
- Run — individual files are created for each row
Files are named automatically: TableName_RowNumber_ColumnName.extension
Example Output
output/
├── DOCUMENTS_1_FILE_DATA.pdf
├── DOCUMENTS_2_FILE_DATA.pdf
├── DOCUMENTS_3_FILE_DATA.docx
├── PHOTOS_1_IMAGE.jpg
├── PHOTOS_2_IMAGE.jpg
└── PHOTOS_3_IMAGE.pngWorking with CLOB Data
CLOB data can be exported through multiple methods:
- CSV export: CLOB content appears directly in CSV cells
- SQL export: Text is embedded in INSERT statement values
- LOB extraction: Saved as individual text files (.txt)
For XML or JSON stored in CLOBs, LOB extraction to individual files makes downstream processing easier.
Working with BLOB Data
BLOB data is best exported using the LOB extraction feature:
- Image data (JPEG, PNG) can be used directly as image files
- PDFs are immediately viewable
- Archives (ZIP) can be extracted as-is
Common LOB Scenarios
| Scenario | Recommended Approach |
|---|---|
| Recovering image files | LOB Extract → save as image files |
| Retrieving PDF documents | LOB Extract → save as PDF files |
| Migrating XML/JSON data | LOB Extract → individual files → import at destination |
| Analyzing CLOB text | CSV Export → analyze in Excel or BI tools |
| Migrating BLOBs to another DB | LOB Extract → files → INSERT via application |
Summary
OraDB DUMP Viewer's LOB extraction feature lets you pull BLOB/CLOB data from .dmp files as individual files — no Oracle needed. Use it for recovering images and documents from legacy systems or in data migration projects.