Jeff Silvis's Blog

Overview

I have found that the metadata type:
dc.format.mimetype (metadata_field_id = 36)
THe field dc.format.mimetype only contains entries for items from before the migration to DSPACE. In general, we will need to use the Format field from the bitstream table. This is valid for both before and after the migration.

dc.format.mimetype

The little shell script below pulls the handles of items that have non-null values for dc.format.mimetype.

query="select handle from metadatavalue,handle where metadata_field_id=36 AND item_id=handle.resource_id AND handle.resource_type_id=2;"
echo $query > temp_sql_file
psql -U dspace_sr  dspace_sr  < temp_sql_file
rm temp_sql_file

This shell script pulls all item handles.

query="select  handle  from handle where handle.resource_type_id=2;"
echo $query > temp_sql_file
psql -U dspace_sr  dspace_sr  < temp_sql_file
rm temp_sql_file

With these two scripts, I was able to find the handles that did and did not have the dc.format.mimetype field populated.

Comparison of metadata pre and post migration to DSPACE

Here is a comparison of pre vs post migration to DSPACE and the metadata fields related to mimetype.

DSPACE Table Element	Present on Pre-Migration (example handle 36676)	Present on Post- Migration (example handle 96677)
dc.format.mimetype	yes	no
Bitstream.name	yes	yes
Bitstream.source	no	yes
Bitstream.description	no	yes
Bitstream.format	yes	yes
Bitstream.user format description	no	no
Bitstream.license	no	yes

The information for the table above came largely from the bitstream table.

Bitstream table for handle 96677:
Bitstream table for handle 36676:

Summary of Bitstream.format

I have found the unique mime types in AgEcon using the bitstream.format field:
application/pdf 45264
application/octet-stream 1
application/vnd.ms-excel 2
The handles for the non-pdf files are:
application/octet-stream
62242
application/vnd.ms-excel
42187
92231
This field will be used to determine mime type.