public TableInfo getTableInfo(string tblname, Transaction tx)
{
RecordFile tcatfile = new RecordFile(tcatInfo, tx);
int reclen = -1;
while (tcatfile.next())
{
if (tcatfile.getString("tblname").Equals(tblname))
{//获取到指定表名称的一条记录长度
reclen = tcatfile.getInt("reclength");
break;
}
}
tcatfile.close();
RecordFile fcatfile = new RecordFile(fcatInfo, tx);
Schema sch = new Schema();
Dictionary <string, int> offsets = new Dictionary <string, int>();
while (fcatfile.next())
{//每次取fcatfile中的一条记录
if (fcatfile.getString("tblname").Equals(tblname))
{
string fldname = fcatfile.getString("fldname");
int fldtype = fcatfile.getInt("type");
int fldlen = fcatfile.getInt("length");
int offset = fcatfile.getInt("offset");
offsets.Add(fldname, offset); //获取一张表中每个字段名称的偏移量
sch.addField(fldname, fldtype, fldlen); //获取一张表的模式信息
}
}
fcatfile.close();
return(new TableInfo(tblname, sch, offsets, reclen));
}
public Constant getVal(string fldname)
{//以常量形式返回指定字段名称的值
if (sch.type(fldname) == Schema.INTEGER)
{
return(new IntConstant(rf.getInt(fldname)));
}
else
{
return(new StringConstant(rf.getString(fldname)));
}
}
