// return null if not found
public List <AtomValue> SelectRecord(AtomValue key, int rootPage)
{
List <AtomValue> wrapper = new List <AtomValue> {
key
};
DBRecord keyDBRecord = new DBRecord(wrapper);
BTreeNode node = BTreeNodeHelper.GetBTreeNode(_pager, rootPage);
BTreeCell cell = _bTree.FindCell(keyDBRecord, node);
List <AtomValue> result = null;
result = ((LeafTableCell)cell)?.DBRecord.GetValues();
return(result);
}
private BTreeNode Delete_leaf_redistri(BTreeNode NodetobeDeleted, DBRecord key, BTreeNode Root)
{
BTreeCell cell;
UInt16 offset;
int indexInOffsetArray;
MemoryPage parentPage = _pager.ReadPage((int)NodetobeDeleted.ParentPage);
BTreeNode parentNode = new BTreeNode(parentPage);
(cell, offset, indexInOffsetArray) = parentNode.FindBTreeCell(key);
//the deleted node is not on the right page of parentNode
if (cell != null)
{
MemoryPage brotherPage = _pager.ReadPage((int)NodetobeDeleted.RightPage);
BTreeNode brotherNode = new BTreeNode(brotherPage);
//If there is a node on the left of the deleted node,it need to be connected to the brother node.
if (indexInOffsetArray >= 1)
{
InternalTableCell leftNodeCell = (InternalTableCell)parentNode.GetBTreeCell(parentNode.CellOffsetArray[indexInOffsetArray - 1]);
MemoryPage leftPage = _pager.ReadPage((int)leftNodeCell.ChildPage);
BTreeNode leftNode = new BTreeNode(leftPage);
leftNode.RightPage = (uint)brotherNode.RawPage.PageNumber;
}
if (brotherNode.NumCells + NodetobeDeleted.NumCells <= MaxCell) //merge
{
//After the merge,one cell in the parentNode will be deleted
parentNode.DeleteBTreeCell(cell);
//merge two node
for (int i = 0; i < NodetobeDeleted.NumCells; i++)
{
brotherNode.InsertBTreeCell(NodetobeDeleted.GetBTreeCell(NodetobeDeleted.CellOffsetArray[i]));
}
DeleteNode(NodetobeDeleted);
}
else //redistribute
{
BTreeCell movedCell = brotherNode.GetBTreeCell(brotherNode.CellOffsetArray[0]);
DBRecord newKey = brotherNode.GetBTreeCell(brotherNode.CellOffsetArray[1]).Key;
NodetobeDeleted.InsertBTreeCell(movedCell);
brotherNode.DeleteBTreeCell(movedCell);
BTreeCell parent_Cell;
UInt16 parent_offset;
int parent_indexInOffsetArray;
(parent_Cell, parent_offset, parent_indexInOffsetArray) = parentNode.FindBTreeCell(key);
InternalTableCell newCell = new InternalTableCell(newKey, (uint)NodetobeDeleted.RawPage.PageNumber);
parentNode.DeleteBTreeCell(parent_Cell);
parentNode.InsertBTreeCell(newCell);
}
}
//The node to be deleted is on the rightpage,the brother node is on the left
else
{
InternalTableCell brotherCell = (InternalTableCell)parentNode.GetBTreeCell(parentNode.CellOffsetArray[parentNode.NumCells - 1]);
MemoryPage brotherPage = _pager.ReadPage((int)brotherCell.ChildPage);
BTreeNode brotherNode = new BTreeNode(brotherPage);
//The right page of brother node should be 0
brotherNode.RightPage = NodetobeDeleted.RightPage;
if (brotherNode.NumCells + NodetobeDeleted.NumCells <= MaxCell) //merge
{
//After the merge,one cell in the parentNode will be deleted
parentNode.DeleteBTreeCell(brotherCell);
//merge two node
for (int i = 0; i < NodetobeDeleted.NumCells; i++)
{
brotherNode.InsertBTreeCell(NodetobeDeleted.GetBTreeCell(NodetobeDeleted.CellOffsetArray[i]));
}
DeleteNode(NodetobeDeleted);
parentNode.RightPage = (uint)brotherNode.RawPage.PageNumber;
}
else //redistribute
{
BTreeCell movedCell = brotherNode.GetBTreeCell(brotherNode.CellOffsetArray[brotherNode.NumCells - 1]);
DBRecord newKey = movedCell.Key;
NodetobeDeleted.InsertBTreeCell(movedCell);
brotherNode.DeleteBTreeCell(movedCell);
BTreeCell parent_Cell;
UInt16 parent_offset;
int parent_indexInOffsetArray;
(parent_Cell, parent_offset, parent_indexInOffsetArray) = parentNode.FindBTreeCell(key);
InternalTableCell newCell = new InternalTableCell(newKey, (uint)NodetobeDeleted.RawPage.PageNumber);
parentNode.DeleteBTreeCell(parent_Cell);
parentNode.InsertBTreeCell(newCell);
}
}
NodetobeDeleted = parentNode;
//deal with parent Nodes
return(Delete_internal_redistribute(NodetobeDeleted, key, Root));
}
public BTreeNode Delete(BTreeCell keyCell, BTreeNode Root)
{
DBRecord key = keyCell.Key;
return(Delete(key, Root));
}
static void AssertCell(BTreeCell c1, BTreeCell c2)
{
Assert.Equal(c1.Types, c2.Types);
AssertDBRecords(c1.Key, c2.Key);
}
public static void AssertCell(BTreeCell c1, BTreeCell c2)
{
Debug.Assert(c1.Types == c2.Types);
AssertDBRecords(c1.Key, c2.Key);
}
