4.7: "Exploding" Metadata Files

Metadata database file types, such as MARC, OAI, CDS/ISIS, BibTex, Refer and ProCite, can be imported into Greenstone but their metadata cannot be IMMEDIATELY viewed or edited in the Librarian Interface. However, you can "explode" the file in the Librarian Interface and view or edit the metadata afterwards. Alternatively, particularly if you are maintaining a master external application, you can go back to the program that created the file, make your corrections, and reimport.

"Exploding" a metadata database file splits it into individual records, with viewable and editable metadata. This process is irreversible: the original metadata file is deleted.

Explodable files have a green icon in the Collection tree. To explode one, right click it and choose "Explode metadata database". A popup window shows options for the exploding process. The "plugin" option specifies the plugin to be used for exploding. In most cases, only one plugin will process a particular type of file, but in some cases, where different file types share the same filename extension, there may be two plugins that both process files with that extension. The "input_encoding" option can be used to specify the encoding of the database. The "metadata_set" option specifies the metadata set to which the new fields generated by exploding should be added. If none is specified, you will be prompted for what to do with each new field in the database: add it as a new element to an existing metadata set, merge with another element, or ignore.

When a file is exploded, a new empty document is created for each record, and the metadata from the record is assigned to the document. These are named using numbers such as 000001.nul, 000002.nul etc. If the "document_field" option is set (to a database field name), the value of this field, if present, will be used for the filename. The exploding process will also try to download the file and use it instead of an empty file. The "document_prefix" and "document_suffix" options can be used to make a valid URL or file path from the document_field value. The "records_per_folder" option can be used to group exploded records into sub-folders. If the database is very large, using this option will accelerate subsequent metadata editing.

Explodability is determined by file extension. In some cases, files may be incorrectly labelled as explodable if they have the same file extension as an explodable file. For example, the ProCite plugin processes files with a .txt extension, but most .txt files are plain text files, not ProCite files.