Persistence & retrieval

CONTENTdm® uses a proprietary, purpose-built, non-relational database for persistence of all metadata, collection data, and indexes. There is no OCLC-approved way of accessing this database directly. Object files themselves are not stored in the database and instead are stored as-is inside a managed folder structure. As of version 2.1, dmBridge accesses thumbnail images and object files directly from the filesystem, without going through CONTENTdm®.

All CONTENTdm® objects have a thumbnail image, which is a highly compressed JPEG image constrained to 160 pixels on a side. A thumbnail image can be accessed in a typical installation at the following URI:

http://my_cdm_server/cgi-bin/thumbnail.exe?CISOROOT=[alias]&CISOPTR=[pointer]

The file of a CONTENTdm® object can be accessed at the following URI:

http://my_cdm_server/cgi-bin/showfile.exe?CISOROOT=[alias]&CISOPTR=[pointer]

This includes full-sized images, for objects that have one.

For image-based objects, a cropped image tile can be downloaded at the following URI:

http://my_cdm_server/cgi-bin/getimage.exe?CISOROOT=[alias]&CISOPTR=[pointer]&DMHEIGHT=[height] &DMWIDTH=[width]&DMX=[offset]&DMY=[offset]&DMSCALE=[0-100]&DMROTATE=[0-360]

These tiles are generated on-the-fly.