Q: InMemory table filter 
Author Message
 Q: InMemory table filter


 We are working with Delphi 1.0 C/S, SQL Links 2.5 and INformix Online 5.01.

 We have lots of problems with the db access. Some of them are:
   - Slowness
   - Insertions don't refresh the dataset (the new record dissapears, not
     in the server but in the local cache).
   - The refresh of the TQuery consists on a reopen (close & open) of the
     query. This operation costs a lot.

 Well, our actual solution is to make a local cache with a InMemory table
to get the insertions (so they aren't lost), and recover a controlable
number of records.
 We made a UpdateSQL component and a Lock component to overcome the
nonupdatable queries like joins and to avoid the refresh :-) of the linked
queries (we have forms with three or more linked queries and a movement in
the master implies the reopen of the others :-().

 Our problem now is that the InMemory tables don't support the Delete method
nor the filtering routines of the BDE. Several possiblities are:

  - Create a field to indicate if the record is deleted. Problem, the Next
    and Prev methods aren't virtual, so we can't know when the dataset
    changes (we don't want to use the OnDataChange event of the linked
    datasource). We can use a calculated field but we are looking for a
    better solution.
  - Copy the inmemory table to other inmemory table (pack), but this is
    too costly (memory and time) if there are many records.    
  - Cope the inmory table into himself but this is costly too and we can't
    remove the records at the end.

  -- Any idea ??? --

PD: There are problems with the insertion too (inmemory tables), it is
always at the end (phisical order).

Miguel Lorenzo Turbon           | Molino del Viento - Meiras

http://www.***.com/ ~burton   | Spain

Mon, 22 Feb 1999 03:00:00 GMT
 [ 1 post ] 

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