referential integrity problem using DbiDoRestructure

hi tunct,
i think you must configure working dir. right to define a RI. because BDE uses the tables from same working dir to create a relation ship between them.

Adjusted points to 200

nope, i also tried doing it in the directory where the exe is located, it's still the same.

hmm, maybe the problem is more difficult than i thought... i'm increasing the score to 200

btw: os = NT4.0

T.

hi tunctm

from my paq,

procedure AddRI(Master, Detail: TTable; MFields, DFields : Array of word ;RIName: string; ModOp, DelOp: RINTQual; RINTNum : Word);
var
  MasterProps, DetailProps: CURProps;
  hDb: hDBIDb;
  TableDesc: CRTblDesc;
  Op: CROpType;
  RInt: RINTDesc;
  MIndex, DIndex: IDXDesc;
  MNo, DNo: Word;
  I : Integer;
begin
  if Master.Active = False then
    raise EDatabaseError.Create('Master table: ' + Master.TableName +
                                ' is not opened');
  if Detail.Active = False then
    raise EDatabaseError.Create('Detail table: ' + Detail.TableName +
                                ' is not opened');

  if Master.Exclusive = False then
    raise EDatabaseError.Create('Table: ' + Master.TableName +
                                ' must be opened exclusively');
  if Detail.Exclusive = False then
    raise EDatabaseError.Create('Table: ' + Detail.TableName +
                                ' must be opened exclusively');

  // Make sure the tables are opened with an index and get their descriptors...
  FillChar(DIndex, sizeof(DIndex), 0);
  FillChar(MIndex, sizeof(MIndex), 0);
  Check(DbiGetIndexDesc(Detail.Handle, 0, DIndex));
  Check(DbiGetIndexDesc(Master.Handle, 0, MIndex));

  // Get the table properties to determine table type...
  Check(DbiGetCursorProps(Master.Handle, MasterProps));
  Check(DbiGetCursorProps(Detail.Handle, DetailProps));

  // If the table is not a Paradox table, raise an error...
  if (MasterProps.szTableType <> szPARADOX) and
     (MasterProps.szTableType <> szDBASE) then
     raise EDatabaseError.Create('Master table: ' + Master.TableName +
                                 ' must be a Paradox or dBASE table type');
  if (DetailProps.szTableType <> szPARADOX) and
     (DetailProps.szTableType <> szDBASE) then
     raise EDatabaseError.Create('Detail table: ' + Detail.TableName +
                                 ' must be a Paradox or dBASE table type');
  if MasterProps.szTableType <> DetailProps.szTableType then
     raise EDatabaseError.Create('Master and Detail tables must be of same type');

  // Blank out the structures...
  FillChar(TableDesc, sizeof(TableDesc), 0);
  FillChar(RInt, sizeof(RInt), 0);
  //  Get the database handle from the table's cursor handle...
  Check(DbiGetObjFromObj(hDBIObj(Master.Handle), objDATABASE, hDBIObj(hDb)));
  // Put the table name in the table descriptor...
  StrPCopy(TableDesc.szTblName, Detail.TableName);
  // Put the table type in the table descriptor...
  TableDesc.szTblType := MasterProps.szTableType;
  // Set the operation type...
  Op := crADD;
  TableDesc.pecrRintOp := @Op;
  // Set the amount of new RI descriptors...
  TableDesc.iRintCount := 1;
  // Connect the table descriptor to the RI descriptor...
  TableDesc.printDesc := @RInt;
  // Setup the RI descriptor...
  // Put in the name of the RI...
  StrPCopy(RInt.szRintName, RIName);
  // Do the restructure on the dependent (detail) table...
  RInt.eType := rintDEPENDENT;
  // Add the master table name...
  StrPCopy(RInt.szTblName, Master.TableName);
  // Modify operations will be restricted (this can be changed to rintCASCADE)...
  RInt.eModOp := ModOp;
  // Delete operations will be restricted (NOTE: rintCASCADE will not work)...
  RInt.eDelOp := DelOp;
  // Only one field in link...
  RInt.iFldCount := high(MFields) + 1;
  // If the tables are Paradox, then put the associated field numbers in the descriptor...
  if (MasterProps.szTableType = szPARADOX) then
  begin
    //
    if RInt.eDelOp = rintCASCADE then
      raise EDatabaseError.Create('Cannot use cascading delete RI with Paradox tables');
    // Put the detail field index in the array...
//    RInt.aiThisTabFld := DIndex.aiKeyFld;
    for i := low(DFields) to High(DFields) do
      RInt.aiThisTabFld[I] := DFields[I];
    // Put the master field index in the array...
//    RInt.aiOthTabFld := MIndex.aiKeyFld;
    for i := low(MFields) to High(MFields) do
      RInt.aiOthTabFld[I] := MFields[I];
    RInt.iRintNum := RINTNum;
  end;

  // If the tables are dBASE, then put the sequence number in the descriptor...
  if MasterProps.szTableType = szDBASE then
  begin
    Check(DbiGetIndexSeqNo(Master.Handle, MIndex.szName, MIndex.szTagName, 0, MNo));
    Check(DbiGetIndexSeqNo(Detail.Handle, DIndex.szName, DIndex.szTagName, 0, DNo));
    // Put the detail field index in the array...
    RInt.aiThisTabFld[0] := DNo;
    // Put the master field index in the array...
    RInt.aiOthTabFld[0] := MNo;
  end;

  try
    Master.Close;
    Detail.Close;
    Check(DbiDoRestructure(hDb, 1, @TableDesc, nil, nil, nil, FALSE));

  finally
    Master.Open;
    Detail.Open;
  end;
end;

Master, Detail: TTable -> must be opened exclusive
MFields, DFields : Array of word -> Field Number(s), not zeroBased,
count must be the same
RIName: string -> unique name of the Referential Integrity
ModOp, DelOp: RINTQual -> rintRESTRICT or rintCASCADE (delOp can only be
rintRESTRICT)
RINTNum : Word -> Index of the Referential Integrity (zeroBased) -> can
allways be zero

following restrictions i have checked out

the field(s) on the detailtable must be primary or secondary indexed

if there are more Referential Integrities as one then the other dependend tables must be closed before adding the new Referential Integrity.

----------------------------------------

hope this helps

meikl

just forgot,

a sample how to call

here the sample, how to call.
table1 is a producttable and holds a VendorID, DepartmentID, InventoryID, and a OtherID, pointed to tables, which holds additional informations.


procedure TForm1.Button1Click(Sender: TObject);
begin
  AddRI(Table2, Table1, [1], [2], 'RIVendorProduct', RINTRestrict, RINTRestrict,0);
  Table2.Close;
  AddRI(Table3, Table1, [1], [3], 'RIDepartmentProduct', RINTRestrict, RINTRestrict,0);
  Table3.Close;
  AddRI(Table4, Table1, [1], [4], 'RIInventoryProduct', RINTRestrict, RINTRestrict,0);
  Table4.Close;
  AddRI(Table5, Table1, [1], [5], 'RIOtherProduct', RINTRestrict, RINTRestrict,0);
  Table2.Open;
  Table3.Open;
  Table4.Open;
end;

meikl

just to mention, that this is delphi-code, no bcb

thanks for the example, meikl. it's very similar to the code i converted from delphi...

ok, the real problem appears to be the secondary index business. but i'd prefer not to constrain myself with that, since it means that i'll have to create the secondary index in run-time, too, which doesn't make life easier; the software refuses to issue the AddIndex() method. so bde API seems to have a general trouble in creating indexes in run-time. if databse desktop can do it, why can't i?

so let's change the question to: "given field and foreign key definitions, create two paradox tables and necessary RI's."

the creation part is no problem, but it's a prerequisite. any suggestions?


T.

thanks for the example, meikl. it's very similar to the code i converted from delphi...

ok, the real problem appears to be the secondary index business. but i'd prefer not to constrain myself with that, since it means that i'll have to create the secondary index in run-time, too, which doesn't make life easier; the software refuses to issue the AddIndex() method. so bde API seems to have a general trouble in creating indexes in run-time. if databse desktop can do it, why can't i?

so let's change the question to: "given field and foreign key definitions, create two paradox tables and necessary RI's."

the creation part is no problem, but it's a prerequisite. any suggestions?

T.

hi tunct,

well, how to create just from scratch
(delphi-code of course)

procedure TForm1.Button1Click(Sender: TObject);
begin
  Table1.DatabaseName := 'pdx';                      //MasterTable
  Table1.tableName := 'OrderHead';
  Table1.FieldDefs.Add('Id',ftInteger,0,True);
  Table1.FieldDefs.Add('AField',ftString,20,False);
  Table1.FieldDefs.Add('BField',ftString,20,False);
  Table1.FieldDefs.Add('CField',ftString,20,False);
  Table1.IndexDefs.Add('Id_PK','Id',[ixPrimary,ixUnique]); //PK

  Table1.CreateTable;                                  //CreateTable

  Table2.DatabaseName := 'pdx';                       //DetailTable
  Table2.tableName := 'OrderDetail';
  Table2.FieldDefs.Add('Id',ftInteger,0,True);
  Table2.FieldDefs.Add('Head_Id',ftInteger,0,True);   //The FK must defined in the structure
  Table2.FieldDefs.Add('AField',ftString,20,False);
  Table2.FieldDefs.Add('BField',ftString,20,False);
  Table2.FieldDefs.Add('CField',ftString,20,False);
  Table2.IndexDefs.Add('Id_PK','Id',[ixPrimary,ixUnique]); //PK

  //Secondary -> give no name to force a creation of an standard Secondary Index (X0?,Y0?)
  Table2.IndexDefs.Add('','Head_Id',[]);

  Table2.CreateTable;                                 //CreateTable

  Table1.Exclusive := True;                           //OpenExclusive
  Table2.Exclusive := True;

  Table1.Open;
  Table2.Open;

  AddRi(Table1,Table2,[1],[2],'RIDetailToHead',RINTRestrict, RINTRestrict,0);  //Add Referential Integrity
end;

hope this helps

meikl

hi meikl,

ok, not giving a name to the 2ndary index did the trick... should've figured out that myself :) thanks.

i'll give you the points if you post an answer.

btw, do you know how to define the RI as "strict"? (that won't affect the grading, though :)

regards,

T.

by "strict". i meant the option seen in the database desktop's RI definition dialog... it's a protection against older paradox versions.

never mind, thanks again.

T.