【转】WinCE数据库之CCeDBDatabase

CCeDBDatabase类提供一系列api函数以操作WinCE下的数据库文件*.db，不过该数据库文件一般由系统自动创建于Database文件夹下面，该文件保存于内存中，仪器重启即丢失。此方式可用于数据量大且短期需要保存数据的系统。其操作具体如下所示：
1、定义数据库对象：
CCeDBDatabase db;

2、创建数据库：
// Create database
CCeDBProp dbprops[3] =
{
CCeDBProp(CCeDBProp::Type_String,PROP_NO,CCeDBProp::Sort_Ascending),
CCeDBProp(CCeDBProp::Type_String,PROP_Name,CCeDBProp::Sort_Ascending),
CCeDBProp(CCeDBProp::Type_UShort,PROP_Age,CCeDBProp::Sort_Ascending)
};
if(!CCeDBDatabase::Exists(_T("Student.db")))
{
db.Create(_T("Student.db"),DB_IDENT_ID,3,dbprops);
}

3、新增记录：
UpdateData(true);
if(!db.Open(_T("Student.db")))
{
MessageBox(_T("Database open Error!"));
return;
}
CCeDBProp props[3];
CCeDBRecord rec;
props[0] = CCeDBProp((LPWSTR)(LPCTSTR)m_No,PROP_NO);
props[1] = CCeDBProp((LPWSTR)(LPCTSTR)m_Name, PROP_Name);
if(db.SeekFirstEqual(props[1]))
{
MessageBox(_T("tiger"));
db.Close();
return;
}
props[2] = CCeDBProp((USHORT)m_Age,PROP_Age);
rec.AddProps(props,3);
if(!db.AddRecord(&rec))
{
MessageBox(_T("Add Record Error!"));
return;
}
db.Close();

4、编辑记录：
UpdateData(true);
if(!db.Open(_T("Student.db")))
{
MessageBox(_T("Database open Error!"));
}

CCeDBRecord rec;
CCeDBProp pProp[2];
// pProp[0]=CCeDBProp((LPWSTR)(LPCTSTR)m_No,PROP_NO);
pProp[0]=CCeDBProp((LPWSTR)(LPCTSTR)m_Name,PROP_Name);
pProp[1]=CCeDBProp((USHORT)m_Age,PROP_Age);
rec.AddProps(pProp,2);
//OK
/* CCeDBProp pProp1[1];
pProp1[0]=CCeDBProp((LPWSTR)(LPCTSTR)m_No,PROP_NO);
db.SeekFirstEqual(pProp1[0]);
db.WriteCurrRecord(&rec);*/
//修改数据OK
//////////////////////////
/* BOOL OldSeekNext=db.m_bAutoSeekNext;
db.m_bAutoSeekNext=true;
db.SeekFirst();
CCeDBRecord temprec;
CCeDBProp* tempProp;
CString strNO,strName;
while(db.ReadCurrRecord(&temprec))
{
tempProp=temprec.GetPropFromIdent(PROP_NO);
strNO=tempProp->GetString();
tempProp=temprec.GetPropFromIdent(PROP_Name);
strName=tempProp->GetString();
if((strNO == m_No)&&(strName == m_Name))
{
if(db.m_bEOF)
db.SeekLast();
else
db.SeekPrev();
db.WriteCurrRecord(&rec);
break;
}
}
db.m_bAutoSeekNext=OldSeekNext;*/
////////////////////////
//定位记录
BOOL OldSeekNext=db.m_bAutoSeekNext;
db.m_bAutoSeekNext=true;
CCeDBProp AimProp[1];
AimProp[0]=CCeDBProp((LPWSTR)(LPCTSTR)m_No,PROP_NO);
if(db.SeekFirstEqual(AimProp[0]))
{
CCeDBRecord temprec;
CCeDBProp *tempProp;
CString strName;
// do
//  {
db.ReadCurrRecord(&temprec);
// tempProp=temprec.GetPropFromIdent(PROP_Name);
// strName=tempProp->GetString();

// MessageBox(strName);
// if(!db.m_bEOF)
//  MessageBox(_T("tiger"));

if(!db.m_bEOF)
db.SeekPrev();
db.DeleteCurrRecord();
/* if(strName == m_Name)
{
db.WriteCurrRecord(&rec);
break;
}*/
// }while(db.SeekNextEqual(AimProp[0]));
}
db.m_bAutoSeekNext=OldSeekNext;
/////////////////////////////////////
db.Close();

5、删除记录：
if(!db.Open(_T("Student.db")))
{
MessageBox(_T("Database open Error!"));
}
//取得列表中选择的记录
POSITION pos=m_CtrlList.GetFirstSelectedItemPosition();
int nItem=m_CtrlList.GetNextSelectedItem(pos);

CString NO=m_CtrlList.GetItemText(nItem,0);
CCeDBProp pProp[1];
pProp[0]=CCeDBProp(NO.GetBuffer(0),PROP_NO);
db.SeekFirstEqual(pProp[0]);

////////////////////
CCeDBRecord rec;
db.ReadCurrRecord(&rec);
CCeDBProp* tempProp;
tempProp=rec.GetPropFromIdent(PROP_NO);
CString strNO=tempProp->GetString();
MessageBox(strNO);
/////////////////////
db.DeleteCurrRecord();
db.Close();

6、遍历记录
m_CtrlList.DeleteAllItems();
if(!db.Open(_T("Student.db")))
{
MessageBox(_T("Database open Error!"));
}

CCeDBProp* pProp;
int nItem=0;
CString str;
BOOL bPrev = db.m_bAutoSeekNext;
db.m_bAutoSeekNext = TRUE;
db.SeekFirst();
CCeDBRecord rec;
while(db.ReadCurrRecord(&rec))
{
pProp=rec.GetPropFromIdent(PROP_NO);
LPWSTR strNO=pProp->GetString();
m_CtrlList.InsertItem(nItem,strNO);
pProp=rec.GetPropFromIdent(PROP_Name);
LPWSTR strName=pProp->GetString();
m_CtrlList.SetItemText(nItem,1,strName);
pProp=rec.GetPropFromIdent(PROP_Age);
USHORT Age=pProp->GetUShort();
str.Format(_T("%d"),Age);
m_CtrlList.SetItemText(nItem,2,str);
}
db.m_bAutoSeekNext = bPrev;
db.Close();