I am planing to include authentication capabilities in my program.
I need information about switching between table records. My current program is only reading the username and password from the first record.
How do I move to subsequent table records?
Dataset has a Next method, that way you may traverse the whole dataset.
qDS.Open ;
while not qDS.EOF do
begin
anyString := qDS.fieldbyname('usern').asString ; // will give you the username
qDS.Next ; // go to the next record in the dataset.
end ;
qDS.close ;
Just use TDataSet.Locate
. In all of the below, I'm using ds
to represent your TDataSet
variable.
UserName := EditUserName.Text;
Password := EditPassword.Text;
if ds.Locate(UserName, ['UserNameField']) then
begin
if ds.FieldByName('Password').AsString = Password then
// Passwords match
else
// Passwords don't match
end
else
// User name not found
To move from one record (row) to the next, simply use ds.Next;
, and to move to the one before use ds.Prior;
. To go to the first row, use ds.First
, and ds.Last
to go to the last one.
This is really basic database programming. You should probably search for a tutorial that explains it and work through it.
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