{//最简单、原始的、可能的查询计划
public Plan createPlan(QueryData data, Transaction tx)
{
//第一步：为每一个出现的表或者视图定义创建一个plan
List <Plan> plans = new List <Plan>();
foreach (string tblname in data.tables())
{
string viewdef = SimpleDB.mdMgr().getViewDef(tblname, tx);
if (viewdef != null)
{
plans.Add(SimpleDB.planner().createQueryPlan(viewdef, tx));
}
else
{
plans.Add(new TablePlan(tblname, tx));
}
}
//第二步：创建所有表计划的叉积运算
Plan p = plans[0];
plans.RemoveAt(0);
foreach (Plan nextplan in plans)
{
p = new ProductPlan(p, nextplan);
}
//第三步：为predicate添加一个选择运算selection
p = new SelectPlan(p, data.pred());
//第四步：做字段名称上的投影运算
p = new ProjectPlan(p, data.fields());
return(p);
}
public int size(string filename)
{//返回指定文件的block数目，在要求文件管理器返回数目之前，先加 S 锁到“end of the file”块上
Block dummyblk = new Block(filename, END_OF_FILE);
concurMgr.sLock(dummyblk);
return(SimpleDB.fileMgr().size(filename));
}
public void recover()
{
doRecover();
int lsn = new CheckpointRecord().writeToLog();
SimpleDB.logMgr().flush(lsn);
}
//---------------------------------------------------------------------------------------
public IndexInfo(string idxname, string tblname, string fldname, Transaction tx)
{
this.idxname = idxname;
this.fldname = fldname;
this.tx = tx;
ti = SimpleDB.mdMgr().getTableInfo(tblname, tx);
si = SimpleDB.mdMgr().getStatInfo(tblname, ti, tx);
}
public override void undo(int txnum)
{
BufferMgr buffMgr = SimpleDB.bufferMgr();
Buffer buff = buffMgr.pin(blk);
buff.setString(offset, val, txnum, -1);
buffMgr.unpin(buff);
}
public void rollback()
{//写一个ROLLBACK日志，然后将这个日志记录写回磁盘
//所有被当前该事务修改过的脏数据页的“修改日志”写回磁盘，再将脏页写回磁盘
SimpleDB.bufferMgr().flushAll(txnum);
doRollback();//回滚当前事务直到看到START日志记录
int lsn = new RollbackRecord(txnum).writeToLog();
SimpleDB.logMgr().flush(lsn);
}
internal void flush()
{//将Page写回磁盘块，若当前Page为脏，那么先将它的日志记录写回磁盘块，再将page写回
if (modifiedBy >= 0)
{
SimpleDB.logMgr().flush(logSequenceNumber);
contents.write(blk);
modifiedBy = -1;//修改的事务id置为负数
}
}
static void Main(string[] args)
{
SimpleDB sdb = new SimpleDB();
sdb.CreateMap();
sdb.printMap();
System.Console.WriteLine("---------------Retrive data-----------------------");
sdb.GetData(2);
}
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddSingleton <SimpleBotUser>();
SimpleDB.ConnectionString = Configuration.GetSection("ConnectionStrings:ConnectionString").Value;
SimpleDB.Banco = Configuration.GetSection("ConnectionStrings:Banco").Value;
SimpleDB.Collection = Configuration.GetSection("ConnectionStrings:Collection").Value;
SimpleDB.Iniciar();
services.AddMvc();
}
public override void undo(int txnum)
{
BufferMgr buffMgr = SimpleDB.bufferMgr();
//将块绑定到（读入）缓冲区
Buffer buff = buffMgr.pin(blk);
//LSN为负数，生成一条临时日志记录，不保存到磁盘
buff.setInt(offset, val, txnum, -1);
buffMgr.unpin(buff);
}
public void commit()
{//写一个COMMIT记录到日志，然后将这个日志记录写回磁盘
//所有被当前该事务修改过的脏数据页，先写“修改日志”到磁盘，再将脏页写回磁盘
SimpleDB.bufferMgr().flushAll(txnum);
//写一个COMMIT记录到日志
int lsn = new CommitRecord(txnum).writeToLog();
//将该日志写回磁盘
SimpleDB.logMgr().flush(lsn);
}
static void doUpdate(string cmd)
{
Planner planner = SimpleDB.planner();
Transaction tx = new Transaction();
int num = planner.executeUpdate(cmd, tx);
tx.commit();
System.Console.WriteLine(num + " records affected");
}
static void doQuery(string cmd)
{
int length;
string format;
Planner planner = SimpleDB.planner();
Transaction tx = new Transaction();
Plan p = planner.createQueryPlan(cmd, tx);
Schema sch = p.schema();
foreach (string fldname in sch.fields())
{
if (sch.type(fldname) == Schema.INTEGER)
{
length = Math.Max(5, fldname.Length) + 2;
format = "{0," + length + "}";
Console.Write(format, fldname);
}
else
{
length = Math.Max(sch.length(fldname), fldname.Length) + 2;
format = "{0," + length + "}";
Console.Write(format, fldname);
}
}
Console.WriteLine();
Scan s = p.open();
while (s.next())
{
foreach (string fldname in sch.fields())
{
if (sch.type(fldname) == Schema.INTEGER)
{
length = Math.Max(5, fldname.Length) + 2;
format = "{0," + length + "}";
Console.Write(format, s.getInt(fldname));
}
else
{
length = Math.Max(sch.length(fldname), fldname.Length) + 2;
format = "{0," + length + "}";
Console.Write(format, s.getString(fldname));
}
}
Console.WriteLine();
}
s.close();
tx.commit();
}
static void Main(string[] args)
{
SimpleDB sdb = new SimpleDB();
System.Console.WriteLine("---------------Set data-----------------------");
sdb.SetData("1", "First data entry");
sdb.SetData(2, new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 });
sdb.SetData('3', "more regular text - key 3 entry");
sdb.SetData("4", "This value will soon be deleted in the hashmap");
sdb.SetData("weird_key", "Any type of key is acceptable");
sdb.SetData("4", 123456);
System.Console.WriteLine("---------------Set data done-----------------------");
System.Console.WriteLine("---------------Print offSets-----------------------");
sdb.CreateMap();
sdb.printMap();
}
public LogMgr(string logfile)
{/* 为制定日志文件创建的管理器，如果日志文件不存在，会用一个空的第一个块创建
* 这个构造函数依赖于一个 FileMgr 的 object 对象（来自server.SimpleDB.filemgr创建于系统初始化时）
* 所以这个构造函数必须要通过先调用server.SimpleDB.initFileMgr之后才能调用*/
this.logfile = logfile;
int logsize = SimpleDB.fileMgr().size(logfile);
if (logsize == 0)
{
appendNewBlock();
}
else
{
currentblk = new Block(logfile, logsize - 1);
mypage.read(currentblk);
currentpos = getLastRecordPosition() + Page.INT_SIZE;
}
}
static void Main(string[] args)
{
log4net.Config.XmlConfigurator.Configure();
SimpleDALConfig.RegistConfigService(new XmlConfigurationService());
SimpleDALConfig.RegistLogService<DALLog4net>();
Console.WriteLine("初始化完成，按任意键下一步");
Console.ReadLine();
using(SimpleDB db = new SimpleDB(""))
{
Console.WriteLine("SimpleDB for MySql已经创建");
string sql = "select * from hb_oauth_sites";
SimpleCommand comm = db.CreateCommand(sql, CommandType.Text);
DataTable table = new DataTable();
DataSet ds = new DataSet();
comm.Fill(ds);
Console.WriteLine("The Final Result count is: {0}", ds.Tables[0].Rows.Count);
}
Console.ReadLine();
using(SimpleDB db = new SimpleDB("oracle"))
{
Console.WriteLine("SimpleDB for Oracle 已经创建");
string sql = "select CUBE, CUBE_Name, method from dual";
SimpleCommand commad = db.CreateCommand(sql, System.Data.CommandType.Text);
Console.WriteLine(commad.CommandText);
}
Console.ReadLine();
}
public TablePlan(string tblname, Transaction tx)
{//根据指定表在查询树种创建一个叶子节点
this.tx = tx;
ti = SimpleDB.mdMgr().getTableInfo(tblname, tx);
si = SimpleDB.mdMgr().getStatInfo(tblname, ti, tx);
}
public void recover()
{/* 将所有被该事务修改过的buffer页flush；从后往前遍历日志记录，回滚所有未提交的事务
* 最后写一个静态检查点记录到日志；这个函数只在系统启动时、在用户事务前调用*/
SimpleDB.bufferMgr().flushAll(txnum);
recoveryMgr.recover();
}
static void Main(string[] args)
{
string cmd, cmdstr;
help();
string dbname = "test-db";
Console.WriteLine("Current database is " + dbname);
string homedir = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
string dbDirectory = Path.Combine(homedir, dbname);
Console.WriteLine("Home directory is " + dbDirectory);
Console.WriteLine("Use the following command to get metadata information;");
Console.WriteLine(" select tblname,reclength from tblcat;");
Console.WriteLine(" select tblname,fldname,type,length,offset from fldcat;");
SimpleDB.init(dbname);
while (true)
{
Console.Write(dbname + ">");
cmd = Console.ReadLine().Trim();
if (cmd.EndsWith(";"))
{
cmd = cmd.Substring(0, cmd.Length - 1);
}
if (cmd.Length == 0)
{
continue;
}
cmdstr = cmd.ToLower();
if (cmdstr == "exit")
{
break;
}
else if (cmdstr == "help")
{
help();
}
else if (cmdstr.StartsWith("select"))
{
try
{
doQuery(cmd);
}
catch (BadSyntaxException)
{
Console.WriteLine("Error SQL command!");
}
}
else if (cmdstr.StartsWith("insert") ||
cmdstr.StartsWith("delete") ||
cmdstr.StartsWith("update") ||
cmdstr.StartsWith("create"))
{
try
{
doUpdate(cmd);
}
catch (BadSyntaxException)
{
Console.WriteLine("Error SQL command!");
}
}
else
{
Console.WriteLine("Unknown command!");
}
}
}
public int executeCreateIndex(CreateIndexData data, Transaction tx)
{
SimpleDB.mdMgr().createIndex(data.indexName(), data.tableName(), data.fieldName(), tx);
return(0);
}
public int executeCreateView(CreateViewData data, Transaction tx)
{
SimpleDB.mdMgr().createView(data.viewName(), data.viewDef(), tx);
return(0);
}
public int executeCreateTable(CreateTableData data, Transaction tx)
{
SimpleDB.mdMgr().createTable(data.tableName(), data.newSchema(), tx);
return(0);
}