Use Sheets for Tabular Data
DEVONthink Pro features its own document type for tabular data named 'sheet'. Sheets resemble spreadsheets and can hold textual data organized in rows and columns. Create a new sheet with Data > New > Sheet, name it, and add some columns with Data > Sheet > New Column or Edit Columns.
To add new rows, use Data > Sheet > New Record; alternatively you can use the contextual menu for all these operations, too. Rearrange columns by dragging their headers with the mouse, sort by a column by clicking its header. Of course, sheets are fully searchable; sheets store plain text and so they do not support rich text, images, or links to other documents yet.