About this task
Several methods are available for retrieving records from the Electronic
Journal. The returned records can be unformatted by sending the unformat(Hashtable
aDataHashtable, Context aContext) message to the format object, which updates
the data elements specified in the format definition within the operation
context. The Journal service allows the application to do the following:
- retrieveLastRecord - This method returns the last record, or null if the
table is empty.
- retrieveLastRecords - This method returns a Vector with the last n records
in descending order of record number (n is passed to the method as an argument).
- retrieveRecords - This method returns a Vector with all records that match
the specified search string (passed as a method argument) in descending order
of record number. This method can also accept as arguments a context and a
Hashtable indexed collection format, and in this case this method unformats
the retrieved records into the operation context as an indexed collection
of keyed collections.
- retrieveRecord - This method returns the record with the record number
specified as an argument, or null if the record does not exist.
These methods return, by default, all the columns defined in the database
table for the retrieved records. An additional argument can be passed to all
the methods to specify which columns are to be retrieved.