Easy to use memory dataset

[cdbc]

Hi
Cool, while you're at it, have a look at "Locate" in TDbf 
I've implemented my own cliendataset with delta and delayed updates, but I just needed support for SQLite backend....
Regards Benny

[aradeonas]

I add this procedures to TBufDataset but I cant compile its package and Lazarus still uses old one,how can I compile it to use new changes?

Code: Pascal  [Select][+][-]

1.     procedure Clear;
2.     Procedure CopyFromDataset(DataSet : TDataSet;CopyData : Boolean=True);

Code: Pascal  [Select][+][-]

1. procedure TCustomBufDataset.Clear;
2. begin
3.  ClearIndexes;
4.  ClearBuffers;
5.  ClearFields;
6. end;
7.  
8. procedure TCustomBufDataset.CopyFromDataset(DataSet: TDataSet; CopyData: Boolean);
9. Var
10.   I  : Integer;
11.   F,F1,F2 : TField;
12.   L1,L2  : TList;
13.   N : String;
14.   OriginalPosition: TBookMark;
15. begin
16.  Clear;
17.  For I:=0 to Dataset.FieldCount-1 do
18.    begin
19.    F:=Dataset.Fields[I];
20.    TFieldDef.Create(FieldDefs,F.FieldName,F.DataType,F.Size,F.Required,F.FieldNo);
21.    end;
22.  CreateDataset;
23.    If CopyData then
24.   begin
25.     Open;
26.     L1:=TList.Create;
27.     Try
28.       L2:=TList.Create;
29.       Try
30.         For I:=0 to FieldDefs.Count-1 do
31.           begin
32.           N:=FieldDefs[I].Name;
33.           F1:=FieldByName(N);
34.           F2:=DataSet.FieldByName(N);
35.           L1.Add(F1);
36.           L2.Add(F2);
37.           end;
38.         DisableControls;
39.         Dataset.DisableControls;
40.         OriginalPosition:=Dataset.GetBookmark;
41.         Try
42.           Dataset.Open;
43.           Dataset.First;
44.           While not Dataset.EOF do
45.             begin
46.             Append;
47.             For I:=0 to L1.Count-1 do
48.               begin
49.               F1:=TField(L1[i]);
50.               F2:=TField(L2[I]);
51.               Case F1.DataType of
52.                 ftFixedChar,
53.                 ftString   : F1.AsString:=F2.AsString;
54.                 ftBoolean  : F1.AsBoolean:=F2.AsBoolean;
55.                 ftFloat    : F1.AsFloat:=F2.AsFloat;
56.                 ftLargeInt : F1.AsInteger:=F2.AsInteger;
57.                 ftSmallInt : F1.AsInteger:=F2.AsInteger;
58.                 ftInteger  : F1.AsInteger:=F2.AsInteger;
59.                 ftDate     : F1.AsDateTime:=F2.AsDateTime;
60.                 ftTime     : F1.AsDateTime:=F2.AsDateTime;
61.                 ftDateTime : F1.AsDateTime:=F2.AsDateTime;
62.                 else         F1.AsString:=F2.AsString;
63.               end;
64.               end;
65.             Try
66.               Post;
67.             except
68.               Cancel;
69.               Raise;
70.             end;
71.             Dataset.Next;
72.             end;
73.         Finally
74.           DataSet.GotoBookmark(OriginalPosition); //Return to original record
75.           Dataset.EnableControls;
76.           EnableControls;
77.         end;
78.       finally
79.         L2.Free;
80.       end;
81.     finally
82.       l1.Free;
83.     end;
84.   end;
85. end;

[balazsszekely]

I add this procedures to TBufDataset but I cant compile its package and Lazarus still uses old one,how can I compile it to use new changes?

Bufdataset is a FPC unit, for the changes to take effect you need to recompile FPC.

[Thaddy]

The code looks good. Why not submit it as a patch?

[aradeonas]

I add this procedures to TBufDataset but I cant compile its package and Lazarus still uses old one,how can I compile it to use new changes?

Bufdataset is a FPC unit, for the changes to take effect you need to recompile FPC.

How?I try what I found but keep getting weird errors. What should I do if I want to debug it?I never done that.

[aradeonas]

The code looks good. Why not submit it as a patch?

Honestly I dont know how and one of the problems was getting and keep Lazarus trunk version OK in my computer, I discussed my problems in another topic.

[balazsszekely]

@aradeonas
http://forum.lazarus.freepascal.org/index.php/topic,29547.0.html

[aradeonas]

@GetMem I read it but I still cant compile it.
I give it another try

[Thaddy]

The code looks good. Why not submit it as a patch?

Honestly I dont know how and one of the problems was getting and keep Lazarus trunk version OK in my computer, I discussed my problems in another topic.

I can likely turn it into a patch that you can submit.

[aradeonas]

I can likely turn it into a patch that you can submit.

It will be very good. Thanks.
Im still trying to compile and check it my self.

[balazsszekely]

What about this? You can run a few tests without recompile:

Code: Pascal  [Select][+][-]

1. type
2.   TBufDatasetHelper = class helper for TCustomBufDataset
3.   private
4.     procedure Clear;
5.     procedure CopyFromDataset(DataSet: TDataSet; CopyData: Boolean);
6.   end;
7.  
8. procedure TBufDatasetHelper.Clear;
9. begin
10.   ClearIndexes;
11.   ClearBuffers;
12.   ClearFields;
13. end;
14.  
15. procedure TBufDatasetHelper.CopyFromDataset(DataSet: TDataSet; CopyData: Boolean);
16. Var
17.   I  : Integer;
18.   F,F1,F2 : TField;
19.   L1,L2  : TList;
20.   N : String;
21.   OriginalPosition: TBookMark;
22. begin
23.  Clear;
24.  For I:=0 to Dataset.FieldCount-1 do
25.    begin
26.    F:=Dataset.Fields[I];
27.    TFieldDef.Create(FieldDefs,F.FieldName,F.DataType,F.Size,F.Required,F.FieldNo);
28.    end;
29.  CreateDataset;
30.    If CopyData then
31.   begin
32.     Open;
33.     L1:=TList.Create;
34.     Try
35.       L2:=TList.Create;
36.       Try
37.         For I:=0 to FieldDefs.Count-1 do
38.           begin
39.           N:=FieldDefs[I].Name;
40.           F1:=FieldByName(N);
41.           F2:=DataSet.FieldByName(N);
42.           L1.Add(F1);
43.           L2.Add(F2);
44.           end;
45.         DisableControls;
46.         Dataset.DisableControls;
47.         OriginalPosition:=Dataset.GetBookmark;
48.         Try
49.           Dataset.Open;
50.           Dataset.First;
51.           While not Dataset.EOF do
52.             begin
53.             Append;
54.             For I:=0 to L1.Count-1 do
55.               begin
56.               F1:=TField(L1[i]);
57.               F2:=TField(L2[I]);
58.               Case F1.DataType of
59.                 ftFixedChar,
60.                 ftString   : F1.AsString:=F2.AsString;
61.                 ftBoolean  : F1.AsBoolean:=F2.AsBoolean;
62.                 ftFloat    : F1.AsFloat:=F2.AsFloat;
63.                 ftLargeInt : F1.AsInteger:=F2.AsInteger;
64.                 ftSmallInt : F1.AsInteger:=F2.AsInteger;
65.                 ftInteger  : F1.AsInteger:=F2.AsInteger;
66.                 ftDate     : F1.AsDateTime:=F2.AsDateTime;
67.                 ftTime     : F1.AsDateTime:=F2.AsDateTime;
68.                 ftDateTime : F1.AsDateTime:=F2.AsDateTime;
69.                 else         F1.AsString:=F2.AsString;
70.               end;
71.               end;
72.             Try
73.               Post;
74.             except
75.               Cancel;
76.               Raise;
77.             end;
78.             Dataset.Next;
79.             end;
80.         Finally
81.           DataSet.GotoBookmark(OriginalPosition); //Return to original record
82.           Dataset.EnableControls;
83.           EnableControls;
84.         end;
85.       finally
86.         L2.Free;
87.       end;
88.     finally
89.       l1.Free;
90.     end;
91.   end;
92. end;        
93.  
94. //...
95. var
96.   BufDataset: TBufDataset;
97. begin
98.   BufDataset := TBufDataset.Create(nil);
99.   BufDataset.CopyFromDataset();
100. end;
101.                  
102.  

[aradeonas]

I tried to recompile but I give this error:

C:\lazarus\fpc\3.0.0\source\packages\fcl-db>C:\lazarus\fpc\3.0.0\bin\i386-win32\make.exe  clean all install INSTALL_PREFIX="C:\lazarus\fpc\3.0.0"
make: Nothing to be done for `clean'.
C:/lazarus/fpc/3.0.0/bin/i386-win32/ppc386.exe fpmake.pp -n -Fu../../rtl -Fu../../packages/paszlib -Fu../../packages/fcl-process -Fu../../packages/hash -Fu../../packages/libtar -Fu../../packages/fpmkunit
Fatal: Can't find unit system used by fpmake
Fatal: Compilation aborted
make: *** [fpmake.exe] Error 1

Also I tried to see if it can find fpc.cfg and it seems it can. for thsi I tried fpc.exe -va command .

[balazsszekely]

@aradeonas
I tried to recompile but I give this error.

It works fine at my side. Did you try the class helper solution?

[aradeonas]

Good call @GetMem. I wanted to do that but recompiling dpc distract me.
Thanks to you I test it and add First to it and now it seems working good enough. I just dont like its memory usage. it takes about triple of simple query that I just copy if its a problem its about TBufDataset and I will look at it.
Here the changed code :

Code: Pascal  [Select][+][-]

1. var
2.   I: integer;
3.   F, F1, F2: TField;
4.   L1, L2: TList;
5.   N: string;
6.   OriginalPosition: TBookMark;
7. begin
8.   Clear;
9.   for I := 0 to Dataset.FieldCount - 1 do
10.   begin
11.     F := Dataset.Fields[I];
12.     TFieldDef.Create(FieldDefs, F.FieldName, F.DataType, F.Size, F.Required, F.FieldNo);
13.   end;
14.   CreateDataset;
15.   if CopyData then
16.   begin
17.     Open;
18.     L1 := TList.Create;
19.     try
20.       L2 := TList.Create;
21.       try
22.         for I := 0 to FieldDefs.Count - 1 do
23.         begin
24.           N := FieldDefs[I].Name;
25.           F1 := FieldByName(N);
26.           F2 := DataSet.FieldByName(N);
27.           L1.Add(F1);
28.           L2.Add(F2);
29.         end;
30.         DisableControls;
31.         Dataset.DisableControls;
32.         OriginalPosition := Dataset.GetBookmark;
33.         try
34.           Dataset.Open;
35.           Dataset.First;
36.           while not Dataset.EOF do
37.           begin
38.             Append;
39.             for I := 0 to L1.Count - 1 do
40.             begin
41.               F1 := TField(L1[i]);
42.               F2 := TField(L2[I]);
43.               case F1.DataType of
44.                 ftFixedChar,
45.                 ftString: F1.AsString := F2.AsString;
46.                 ftBoolean: F1.AsBoolean := F2.AsBoolean;
47.                 ftFloat: F1.AsFloat := F2.AsFloat;
48.                 ftLargeInt: F1.AsInteger := F2.AsInteger;
49.                 ftSmallInt: F1.AsInteger := F2.AsInteger;
50.                 ftInteger: F1.AsInteger := F2.AsInteger;
51.                 ftDate: F1.AsDateTime := F2.AsDateTime;
52.                 ftTime: F1.AsDateTime := F2.AsDateTime;
53.                 ftDateTime: F1.AsDateTime := F2.AsDateTime;
54.                 else
55.                   F1.AsString := F2.AsString;
56.               end;
57.             end;
58.             try
59.               Post;
60.             except
61.               Cancel;
62.               raise;
63.             end;
64.             Dataset.Next;
65.           end;
66.         finally
67.           DataSet.GotoBookmark(OriginalPosition); //Return to original record
68.           Dataset.EnableControls;
69.           EnableControls;
70.         end;
71.       finally
72.         L2.Free;
73.       end;
74.     finally
75.       l1.Free;
76.     end;
77.     First;
78.   end;
79. end;

[JuhaManninen]

I can likely turn it into a patch that you can submit.

It will be very good. Thanks.
Im still trying to compile and check it my self.

Oh, you should really learn to make patches yourself. Besides, it is extremely easy. Just one "svn diff" command or in TortoiseSVN "Create patch". Doesn't get much simpler.
I understood you are making code for the online package manager. Then you surely must create patches.

BTW, what problems you had with Lazarus trunk version in your computer? Where was it discussed?