From:   "Manuel Candela" <msca53@h...>
Date:  Mon Jul 7, 2003  11:17 pm
Subject:  Using dbfs (Local database)

 
 
I expect of this files that they have some value as tools to manage existing
dbase files, and to create
new files too.
Subs and funcs are "universal" ones in a sense: if you figure out other
structures (called dictionaries
too) the same ideas could be applied.

Regards!
Manuel Candela
_________________________________________________________________
 
Some observations:
1- To travel the table:
a- Sequentially -> dbskip(n) where n indicates how many registrations
from the current one
Yes you advances, chequear eof (); but cheqear bof ().
b- Aleatorily -> dbgoto(n) where n indicates the number of the objective
registration.

2- To obtain data of a field, invoke
fieldget(i),
where i is the position of the field like it was defined when creating
the table.
If this procedure is uncomfortable, just use
i = fieldpos(nameOfField).
It could be useful an include file with significant definitions for the
indexes
of the fields.
If definitively the name of the fields is known, you could use something
as:
defstr campo1
campo1 = fielget(fieldpos (campo1))
being assumed that it is a string.

3- To write data to a field it should be used
fieldput(i, cString, any) for a string
fieldput(i, any, number) for a numeric field
Date fields and memos are worked as strings. For logical fields use (.F.,
.T.),
which are numbers..
When are fields type memo, the recommended procedure is
richedit.text = fieldget(x),
and but ahead
if richedit.modified then
fieldput(x, richedit.text, anynumber <> -1)
end if
If what is sought is a forced update, use
fieldput(x, text, -1)

4- recno() it returns the number of the pointed register,
fcount() it returns the count of the fields of the table.
dbZap annihilates the data of the table.
dbgotop leaves us in the first register of the table
dbgobottom leaves us in the last one
dbAppend adds a clean register at the end of the table (it should de
called dbAppendBlank)

5- dbLocate() and dbScan() were addet to illustrate the use of the previous
procedures

6- The procedures in <dbt.inc>, they are delicate and therefore they should
be considered as
hidden.

7- The added example this organized one as a test session. If you are able
to find
the correct order, everything would be clarified.

WHAT WILL COME SOON

1- The possibility to open several charts in the same application, or even
better, QDbase!
2- Regarding indexes, I prefer to accumulate the data of the searches in an
array and at
the same time their respective register number and then to travel using
dbgoto(x). And
clear, can the arrays be ordered and to write to a file (or to a DBase
table?). Will we See..


PS
Any observation, suggestion, critic, addition, etc.. it will be well
received.
I want to mention these two names:
Rick Spence
Stephen J. Straley,
co-developers of Clipper-Dbase.