FROG and TURTLE: visual bridges between files and object-oriented data

The problem of translating database objects into a flat format to be written out in a flat Ascii file or, conversely, translating the contents of a file into a complex database object arises in several applications. It is especially important in scientific database applications, where file-based communication with external programs (e.g., visualization packages or model simulations) is very common. We introduce Frog, a visual tool that can be used to specify translations between database objects and flat files, requiring no programming by the user. The tool can deal with objects of arbitrary complexity, without the object complexity being directly reflected in the complexity of the corresponding visual interaction. Based on the visual actions of the user, the tool stores enough information in a map-file, whose contents are used at run-time by another tool, Turtle, to translate any chosen database object into the appropriate file layout. The tool has been developed as part of the ZOO desktop experiment management environment and has been used by a few experimental scientists with success.