Excel Documents
excel

DataNucleus supports persisting/retrieving objects to/from Excel documents (using the datanucleus-excel plugin) which makes use of the Apache POI project. Simply specify your "connectionURL" as follows

datanucleus.ConnectionURL=excel:file:myfile.xls

replacing "myfile.xls" with your filename, which can be absolute or relative. This connects to a file on your local machine. You then create your PMF/EMF as normal and use JDO/JPA as normal.

There are tutorials available for use of DataNucleus with Excel for JDO and for JPA

Things to bear in mind with Excel usage :-

  • Querying can be performed using JDOQL or JPQL. Any filtering/ordering will be performed in-memory
  • Relations : A spreadsheet cannot store related objects directly, since each object is a row of a particular worksheet. DataNucleus gets around this by storing the String-form of the identity of the related object in the relation cell.