* Allow descendentsto set default buffer size

packages/fcl-db/src/base/dataset.inc

@@ -1127,6 +1127,11 @@ begin
   end;
 end;
 
+function TDataset.GetDefaultBufferCount : Cardinal;
+
+begin
+  Result:=DefaultBufferCount;
+end;
 
 procedure TDataSet.RecalcBufListSize;
 
@@ -1146,7 +1151,11 @@ begin
   if IsUniDirectional then
     ABufferCount := 1
   else
-    ABufferCount := DefaultBufferCount;
+    begin
+    ABufferCount := GetDefaultBufferCount;
+    if aBufferCount<2 then
+      aBufferCount:=2;
+    end;  
 
   for i := 0 to MyDataSourceCount - 1 do
     for j := 0 to MyDataSources[i].DataLinkCount - 1 do

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

@@ -1723,6 +1723,7 @@ type
     procedure SetSparseArrays(AValue: Boolean);
     procedure DoInsertAppendRecord(const Values: array of const; DoAppend : boolean);
   protected
+    function GetDefaultBufferCount: Cardinal; virtual;
     procedure RecalcBufListSize;
     procedure ActivateBuffers; virtual;
     procedure BindFields(Binding: Boolean);