'Expressions' are the individual musical pieces that are contained in a 'Source'. For every piece contained in a source, a separate 'Expression' entry must be created. Once an 'Expression' entry is created, it is saved as an 'cmo_expression' entity and automatically assigned a number. The expressions contained in a source can then be added to their 'Source' so that they will be linked, and the links to all individual expression pages will appear on their respective 'Source' page.

To create an 'Expression' for an individual piece contained in a source, first click on the 'Editor' tab in the left side of the CMO Source Catalog home page. From the drop-down menu, selct 'Create new catalogue entry', and then from the CMO Content Generator page, choose 'Expression'. This will bring you to the 'Expression' entry page where all of the associated expression metadata can be entered.

Using the Excel index for the Source, you can create 'Expression' entries for each piece by adding all the metadata for each 'Expression'. The primary metadata fields are as follows:

• CMO Identifier
• RISM Identifier
• Title (original, main, alternative, Index title, etc.)
• Composer (and link to the cmo_person entry for the composer)
• Incipit (original, main, normalized)
• Language
• Tempo
• Usul
• Makam
• Genre

These fields can be copied and pasted from the source index, or assigned by the catalogue editor. Additional metadata fields are available for lyricist, and various types of annotations.