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Maximus · Guest

Hi all,

I am trying to create an update program that will scan two databases,
the clients database and the new updated database, for any changes,
i.e. new fields, longer field lengths or new tables, etc.

I can add new tables and amend field lengths without a hitch but when
I try to add a new field to a table I get an array of results. Some
tables will allow a field to be added whereas others will bring up
errors such as "Number is out of range" or "Invalid field
descriptor".

Has anyone seen these errors before and could you please explain why I
might be getting these? Thank you in advance for any help.

P.S. The code i am using to add a new field is below:

procedure TLodgeUpdateForm.AddField(Table : TTable; FldName : String;
FldType,
FldSubType,FldSize:Integer);
type
FLDDescs = array [1..100] of FLDDesc; // these are kludges for
ease of addressing
PFLDDescs = ^FLDDescs;
CROpTypes = array [1..100] of CROpType;
PCROpTypes = ^CROpTypes;
var
Props: CURProps;
hDb: hDBIDb;
TableDesc: CRTblDesc;
pFields: pFLDDescs;
pOp: pCROpTypes;
i:Integer;
begin
// Make sure table is opened exclusively
If (Table.Active and Not Table.Exclusive) Then Table.Close;
If (Not Table.Exclusive) Then Table.Exclusive := True;
If (Not Table.Active) Then Table.Open;
try
Check(DbiGetCursorProps(Table.Handle, Props));
pFields := AllocMem((props.iFields+1) * sizeof(FLDDesc));
pOp := AllocMem((props.iFields+1) * sizeof(CROpType));
Check(DbiGetFieldDescs(table.Handle,@PFields[1]));
for i := 1 to props.iFields do // retain existing fields
pop^[i] := crNOOP;
i := props.iFields + 1;
pOp^[i] := crADD;
with PFields^[i] do
begin
StrCopy(szName,PChar(FldName));
iFldType := FldType;
ISubType := FldSubType;
IUnits1 := FldSize;
end;
FillChar(tabledesc,sizeof(CRTblDesc),#0);
with tabledesc do
begin
StrPCopy(szTblName,Table.TableName);
StrCopy(szTblType,szParadox);
bPack := True;
iFldCount := props.iFields+1;
pecrFldOp := @pop^[1];
pfldDesc := @pfields^[1];
end;
Check(DbiGetObjFromObj(hDBIObj(Table.Handle), objDATABASE,
hDBIObj(hDb)));
Table.Close;// table must be closed as restructure requires
exclusive access
Check(DbiDoRestructure(hdb,1,@tabledesc,nil,nil,nil,False));
finally
FreeMem(PFields);
FreeMem(pOp);
end;
end;