Category : Pascal Source Code
Archive   : PASS_ALL.ZIP
Filename : TI426.ASC

PRODUCT : TURBO PASCAL DATABASE TOOLBOX NUMBER : 426
VERSION : 4.0
OS : MS-DOS, PC-DOS
DATE : AUGUST 29, 1988 PAGE : 1/2

TITLE : DATABASE TOOLBOX SUGGESTIONS AND CORRECTIONS




This handout addresses some problems which have been reported by
users of the Turbo Pascal DataBase ToolBox version 4.0

Correction

When accessing an Index File that allows duplicate keys and has
greater than 32K records, the Index Key routines, FindKey and
SearchKey will be unsuccessful in finding keys for records past
32K. By making the following changes to TACCESS.PAS, this
problem will be corrected. Please make sure that any changes are
made to a backup copy of the Database Toolbox, not the original.

1. In the TaCompKeys procedure change the old code to look as
follows:

begin
if TaKeyStr(K1) = TaKeyStr(K2) then
begin
if not Dup or (DR1 = DR2) then
TaCompKeys := 0
else
if DR1 > DR2 then
TaCompKeys := 1
else
TaCompKeys := -1;
end
else
if TaKeyStr(K1) > TaKeyStr(K2) then
TaCompKeys := 1
else
TaCompKeys := -1;
end;


2. Save the changes to TACCESS.PAS. Call TaBuild for each
.TYP file to create a new TACCESS.TPU file. Rebuild all Index
Files.


Recommended Suggestion

Users have reported unusual errors occurring in their DataBase
ToolBox programs. Many of these errors can be solved by running













PRODUCT : TURBO PASCAL DATABASE TOOLBOX NUMBER : 426
VERSION : 4.0
OS : MS-DOS, PC-DOS
DATE : AUGUST 29, 1988 PAGE : 2/2

TITLE : DATABASE TOOLBOX SUGGESTIONS AND CORRECTIONS




TaBuild with the /W+ option to display the worksheet. The
worksheet will show that 1,000 records will be the expected size
of the Data File. It is necessary that this value be changed to
reflect the maximum number of records possible for the Data File.
The data segment overhead for specifying 100,000 records as
opposed to 1,000 records is approximately 24 bytes additional per
defined IndexFile.

For existing Data Files, where greater than 1,000 records are
expected, it is recommended that you build a new TACCESS unit
using the worksheet to set the maximum number of records. This
requires that all Index Files be rebuilt.