public int DeleteRecords(Expression condition, string primaryKeyName, List <AttributeDeclaration> attributeDeclarations, int rootPage)
{
BTreeNode node = BTreeNodeHelper.GetBTreeNode(_pager, rootPage);
BTreeNode newRoot = _bTree.DeleteCells(node, condition, primaryKeyName, attributeDeclarations);
return(newRoot.RawPage.PageNumber);
}
public int CreateIndex(int tableRootPage, string indexedColumnName, List <AttributeDeclaration> attributeDeclarations)
{
BTreeNode indexRoot = _bTree.OccupyNewTableNode();
BTreeNode tableRoot = BTreeNodeHelper.GetBTreeNode(_pager, tableRootPage);
int indexedColumnIndex = attributeDeclarations.FindIndex(x => x.AttributeName == indexedColumnName);
foreach (BTreeCell tableCell in _bTree.LinearSearch(tableRoot))
{
AtomValue indexedValue = ((LeafTableCell)tableCell).DBRecord.GetValues()[indexedColumnIndex];
AtomValue primaryKey = ((LeafTableCell)tableCell).Key.GetValues()[0];
// List<AtomValue> indexPrimaryKeyPair = new List<AtomValue>() { indexedValue, primaryKey };
List <AtomValue> wrappedPrimaryKey = new List <AtomValue>()
{
primaryKey
};
DBRecord wrappedKey = new DBRecord(new List <AtomValue>()
{
indexedValue
});
// DBRecord wrappedValues = new DBRecord(indexPrimaryKeyPair);
DBRecord wrappedValues = new DBRecord(wrappedPrimaryKey);
indexRoot = _bTree.InsertCell(indexRoot, wrappedKey, wrappedValues);
}
return(indexRoot.RawPage.PageNumber);
}
// return new root page number
public int InsertRecord(List <AtomValue> values, AtomValue key, int rootPage)
{
BTreeNode node = BTreeNodeHelper.GetBTreeNode(_pager, rootPage);
DBRecord wrappedKey = new DBRecord(new List <AtomValue>()
{
key
});
DBRecord wrappedValues = new DBRecord(values);
BTreeNode newRoot = _bTree.InsertCell(node, wrappedKey, wrappedValues);
return(newRoot.RawPage.PageNumber);
}
public List <List <AtomValue> > SelectRecords(SelectStatement selectStatement, string primaryKeyName, List <AttributeDeclaration> attributeDeclarations, int rootPage)
{
BTreeNode node = BTreeNodeHelper.GetBTreeNode(_pager, rootPage);
List <BTreeCell> cells = _bTree.FindCells(node, selectStatement.Condition, primaryKeyName, attributeDeclarations);
List <List <AtomValue> > rows = new List <List <AtomValue> >();
foreach (BTreeCell cell in cells)
{
List <AtomValue> row = ((LeafTableCell)cell).DBRecord.GetValues();
rows.Add(row);
}
return(rows);
}
// 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 static void TestInsertRandomRecord(int maxCell)
{
string dbPath = "./testdbfile.minidb";
File.Delete(dbPath);
Pager pager = new Pager(dbPath);
FreeList freeList = new FreeList(pager);
BTreeController controller = new BTreeController(pager, freeList);
RecordContext recordManager = new RecordContext(pager, controller);
// create new table
CreateStatement createStatement = GetCreateStatement();
int newRoot = recordManager.CreateTable();
// insert
BTreeNode node;
InsertStatement insertStatement;
int key;
int newRootAfterInsert = newRoot;
int i;
for (i = 0; i < maxCell; i++)
{
(insertStatement, key) = GetInsertStatement(1);
AtomValue atomValue = GetAtomValue(key);
newRootAfterInsert = recordManager.InsertRecord(insertStatement.Values, atomValue, newRootAfterInsert);
Console.WriteLine(key);
Debug.Assert(newRoot == newRootAfterInsert);
}
node = BTreeNodeHelper.GetBTreeNode(pager, newRootAfterInsert);
BTreeNodeHelper.VisualizeIntegerTree(pager, node);
Console.WriteLine();
for (i = 0; i < maxCell; i++)
{
(insertStatement, key) = GetInsertStatement(1);
AtomValue atomValue = GetAtomValue(key);
newRootAfterInsert = recordManager.InsertRecord(insertStatement.Values, atomValue, newRootAfterInsert);
Console.WriteLine(key);
}
node = BTreeNodeHelper.GetBTreeNode(pager, newRootAfterInsert);
BTreeNodeHelper.VisualizeIntegerTree(pager, node);
pager.Close();
}
/// <summary>
/// Search the leaf nodes linearly.
/// </summary>
/// <param name="root">the root node of the B+ tree</param>
/// <returns></returns>
public IEnumerable <BTreeCell> LinearSearch(BTreeNode root)
{
BTreeNode startNode = FindMin(root);
while (true)
{
foreach (var cell in startNode)
{
yield return(cell);
}
if (startNode.RightPage == 0)
{
break;
}
startNode = BTreeNodeHelper.GetBTreeNode(_pager, (int)startNode.RightPage);
}
}
