private Dictionary <string, IndexBlock> GetIndexDict(FileStream fileStream, TableBlock tableBlock)
{
Dictionary <string, IndexBlock> indexDict = new Dictionary <string, IndexBlock>();
long indexBlockHeadPos = tableBlock.IndexBlockHeadPos;
IndexBlock currentIndexBlock = fileStream.ReadBlock <IndexBlock>(indexBlockHeadPos);
tableBlock.IndexBlockHead = currentIndexBlock;
currentIndexBlock.TryLoadNextObj(fileStream);// 此时的currentIndexBlock是索引块的头结点。
while (currentIndexBlock.NextObj != null)
{
SkipListNodeBlock[] headNodes = GetHeadNodesOfSkipListNodeBlock(fileStream, currentIndexBlock.NextObj);
currentIndexBlock.NextObj.SkipListHeadNodes = headNodes;
SkipListNodeBlock tailNode = GetTailNodeOfSkipListNodeBlock(fileStream, currentIndexBlock.NextObj);
currentIndexBlock.NextObj.SkipListTailNode = tailNode;
foreach (SkipListNodeBlock headNode in currentIndexBlock.NextObj.SkipListHeadNodes)
{
if (headNode.RightPos == tailNode.ThisPos)
{
headNode.RightObj = tailNode;
}
}
currentIndexBlock.NextObj.TryLoadNextObj(fileStream);
indexDict.Add(currentIndexBlock.NextObj.BindMember, currentIndexBlock.NextObj);
currentIndexBlock = currentIndexBlock.NextObj;
}
return(indexDict);
}
/// <summary>
/// 删除数据库文件里的某个表及其所有索引、数据。
/// </summary>
/// <typeparam name="T"></typeparam>
public bool DeleteTable <T>() where T : Table
{
Type type = typeof(T);
if (!this.tableBlockDict.ContainsKey(type))
{
return(false);
}
// 删除表、索引和数据。
FileStream fs = this.fileStream;
Transaction ts = this.transaction;
ts.Begin();
try
{
TableBlock table = this.tableBlockDict[type];
ts.Delete(table);
long currentIndexPos = table.IndexBlockHeadPos;
IndexBlock IndexHead = fs.ReadBlock <IndexBlock>(currentIndexPos);// 此时指向IndexBlock头结点
ts.Delete(IndexHead);
// 删除数据块。
{
IndexHead.TryLoadNextObj(fs);
IndexBlock currentIndex = IndexHead.NextObj;// 此时指向PK
ts.Delete(currentIndex);
DeleteDataBlocks(currentIndex, fs, ts);
}
// 删除索引块和skip list node块。
{
IndexBlock currentIndex = IndexHead;
while (currentIndex.NextPos != 0)
{
currentIndex.TryLoadNextObj(fs);
ts.Delete(currentIndex.NextObj);
DeleteSkipListNodes(currentIndex, fs, ts);
currentIndex = currentIndex.NextObj;
}
}
this.tableBlockDict.Remove(type);
this.tableIndexBlockDict.Remove(type);
ts.Commit();
return(true);
}
catch (Exception ex)
{
ts.Rollback();
throw ex;
}
}
/// <summary>
/// 把指定的表包含的所有索引的所有skip list node和key value信息都画到图片上。
/// </summary>
/// <param name="nextTable"></param>
/// <param name="dir"></param>
/// <param name="db"></param>
private static void PrintTableBlock(TableBlock table, string dir, string prefix, FileDBContext db)
{
FileStream fs = db.GetFileStream();
long indexBlockHeadPos = table.IndexBlockHeadPos;
IndexBlock indexBlockHead = fs.ReadBlock <IndexBlock>(indexBlockHeadPos);
IndexBlock previousIndex = indexBlockHead;
while (previousIndex.NextPos != 0)
{
previousIndex.TryLoadNextObj(fs);
IndexBlock index = previousIndex.NextObj;
PrintIndexBlock(table, index, dir, prefix, db);
previousIndex = index;
}
}
//static readonly Brush indexBrush = new LinearGradientBrush(new Rectangle(0, 0, Consts.indexBlockLength, bmpHeight), Color.DarkGoldenrod, Color.LightGoldenrodYellow, 0f);
private static void DrawIndex(FileDBContext db, Bitmap[] bmps)
{
TableBlock tableBlockHead = db.GetTableBlockHeadNode();
TableBlock previousTable = tableBlockHead;
while (previousTable.NextPos != 0)
{
//previousTable.TryLoadNextObj(fs);
TableBlock table = previousTable.NextObj;
IndexBlock currentIndex = table.IndexBlockHead;
while (currentIndex != null)
{
long index = currentIndex.ThisPos.PagePos() / Consts.pageSize;
Bitmap bmp = bmps[index];
Graphics g = Graphics.FromImage(bmp);
int startPos = (int)(currentIndex.ThisPos - Consts.pageSize * index);
int length = currentIndex.ToBytes().Length;
Brush brush = new LinearGradientBrush(new Point(startPos, 0), new Point(startPos + length, 0), Color.DarkGray, Color.LightGray);
g.FillRectangle(brush, startPos, 1, length, bmpHeight - 1);
g.DrawRectangle(boundPen, startPos, 1, length, bmpHeight - 1);
g.Dispose();
currentIndex.TryLoadNextObj(db.GetFileStream());
currentIndex = currentIndex.NextObj;
}
//while (currentIndex.NextPos != 0)
//{
// long index = currentIndex.NextObj.ThisPos.PagePos() / Consts.pageSize;
// Bitmap bmp = bmps[index];
// Graphics g = Graphics.FromImage(bmp);
// int startPos = (int)(currentIndex.NextObj.ThisPos - Consts.pageSize * index);
// int length = currentIndex.NextObj.ToBytes().Length;
// Brush brush = new LinearGradientBrush(new Point(startPos, 0), new Point(startPos + length, 0), Color.DarkGray, Color.LightGray);
// g.FillRectangle(brush, startPos, 1, length, bmpHeight - 1);
// g.DrawRectangle(boundPen, startPos, 1, length, bmpHeight - 1);
// g.Dispose();
// currentIndex = currentIndex.NextObj;
//}
previousTable = table;
}
}