fcl-db: bufdataset: when data are written to BLOB field (using TBufBlobStream) assign new write blob buffer to BLOB field in record buffer. So new data are there before Post.

(setting FieldByName('blob').AsString := '...' does not save data to field until record is posted)
Bug #25648

git-svn-id: trunk@26604 -

packages/fcl-db/src/base/bufdataset.pas

@@ -2684,12 +2684,10 @@ begin
         DatabaseError(SFieldIsNull);
       if not assigned(bufblob.BlobBuffer) then
         begin
-        FBlobBuffer := GetNewBlobBuffer;
-        bufblob.BlobBuffer := FBlobBuffer;
-        LoadBlobIntoBuffer(FieldDefs[Field.FieldNo-1],@bufblob);
-        end
-      else
-        FBlobBuffer := bufblob.BlobBuffer;
+        bufblob.BlobBuffer := GetNewBlobBuffer;
+        LoadBlobIntoBuffer(FieldDefs[Field.FieldNo-1], @bufblob);
+        end;
+      FBlobBuffer := bufblob.BlobBuffer;
       end
     else if Mode=bmWrite then
       begin
@@ -2699,6 +2697,9 @@ begin
         FBlobBuffer^.OrgBufID := bufblob.BlobBuffer^.OrgBufID
       else
         FBlobBuffer^.OrgBufID := -1;
+      bufblob.BlobBuffer := FBlobBuffer;
+      // redirect pointer in current record buffer to new write blob buffer
+      Field.SetData(@bufblob);
       FModified := True;
       end;
 end;

packages/fcl-db/tests/testfieldtypes.pas

@@ -169,7 +169,7 @@ const
 
   testBlobValuesCount = 6;
   testBlobValues : Array[0..testBlobValuesCount-1] of ansistring = (
-    'Test deze Blob',    // common value
+    'Test this Blob',    // common value
     '',                  // empty value
     'a'#0'b'#13#10#1'c', // binary data
     '''":a',             // single quotes
@@ -615,39 +615,41 @@ begin
   TSQLDBConnector(DBConnector).Connection.ExecuteDirect('create table FPDEV2 (ID int,FT '+FieldtypeDefinitions[ftblob]+')');
   TSQLDBConnector(DBConnector).CommitDDL;
 
-  TSQLDBConnector(DBConnector).Connection.ExecuteDirect('insert into FPDEV2 (ID,FT) values (1,''Test deze blob'')');
+  TSQLDBConnector(DBConnector).Connection.ExecuteDirect('insert into FPDEV2 (ID,FT) values (1,''Test this blob'')');
 
   with TSQLDBConnector(DBConnector).Query do
     begin
     sql.clear;
     sql.add('select * from FPDEV2');
     Open;
-    fields[1].ProviderFlags := [pfInUpdate]; // blob niet in de where
+    AssertEquals('Test this blob', Fields[1].AsString);
+    Fields[1].ProviderFlags := [pfInUpdate]; // Blob is not in the where
     UpdateMode := upWhereAll;
 
-    AssertEquals('Test deze blob',fields[1].AsString);
-    edit;
-// Dat werkt niet lekker, omdat de stream vernield wordt...
-//    fields[0].asstring := 'Deze blob is gewijzigd!';
+    Edit;
+    s := 'This blob has changed!';
+    Fields[1].AsString := s;
+    AssertEquals(s, Fields[1].AsString); // test before Post
+    Cancel;
+    AssertEquals('After Cancel', 'Test this blob', Fields[1].AsString); // original value
 
-    With Createblobstream(fields[1],bmwrite) do
+    Edit;
+    With CreateBlobStream(Fields[1], bmWrite) do
       begin
-      s := 'Deze blob is gewijzigd!';
+      s := 'This blob has changed!';
       WriteBuffer(Pointer(s)^,Length(s));
-      post;
-      free;
+      Post;
+      Free;
       end;
-    AssertEquals('Deze blob is gewijzigd!',fields[1].AsString);
+    AssertEquals('After Post', s, Fields[1].AsString);
 
     ApplyUpdates(0);
-
     TSQLDBConnector(DBConnector).Transaction.CommitRetaining; // For debug-purposes
+    Close;
 
-    close;
-
-    open;
-    AssertEquals('Deze blob is gewijzigd!',fields[1].AsString);
-    close;
+    Open;
+    AssertEquals(s, Fields[1].AsString);
+    Close;
     end;
 end;