• Description:
  

Appendix A - Powerbase as an Impulse server

The following is a description of the Impulse "methods" understood by Powerbase, given in the standard format recommended by Computer Concepts. Users wishing to write their own Impulse tasks to communicate with Powerbase will need this information. They will also need details of the SWIs to which Impulse will respond, and this information is obtainable from Computer Concepts.

• GetPathname
• Selection <string>
• ParseQuery <string>
• GetField <tag>
• GetRecord
• PutRecord
• ExpandCode <string>
• GetExpanded <string>
• NextMatch

Description:

GetPathname specifies an "object" i.e. a Powerbase database. If Powerbase has the required database open it replies with the full pathname of the object, otherwise it returns an error message. Example of use:

Selection <string> tells Powerbase about a field, or group of fields, in which the caller is interested. The fields are specified as a list of tags, separated by any suitable character (e.g. "/" or ","). The same separator must appear at the very end of the tag-list. Powerbase replies with the maximum data-length of the combined fields in the selection. Example of use:

ParseQuery <string> informs Powerbase of the criteria to be used in selecting records to transmit to the caller. The parameter is a standard Powerbase search formula and Powerbase replies with the title which would normally appear at the head of one of its printed lists. Example of use:

GetField <tag> requests from Powerbase the data in the specified field of the next record which matches the preceding ParseQuery command. When Powerbase replies to the GetField command the calling task should respond with an Impulse_FetchData, specifying the address and length of the buffer to be used, and then wait for an Impulse_Receive event (reason code &204) before reading the buffer. Example of use:

ExpandCode <string> requests the expanded form of a code used in a field linked to a validation table. The parameter string consists of the code itself, then a space, then the name of the validation table with the number of the linked column appended. Example of use:

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