Windows利用Qt AxObject使用ADO访问数据库.doc

Windows利用Qt AxObject使用ADO访问数据库1.介绍使用Qt在Windows下编程，有时候需要使用COM组件。在Qt中，可以用以下几种方式访问COM组件：1. 通过VC等其他语言对要使用的COM封装成动态链接库，然后利用QLibrary加载并使用这些动态链接库2. 使用QAxObject这个类直接操作COM组件如果Qt程序要在Windows平台下使用微软提供的数据库，如Access和SQL Server。虽然可以同QSqlDatabase以ODBC的方式访问Access或SQL Server，但这种方式显然不如ADO来的效率更高一些。如果要使用MySQL,Oracle等其他数据库，还是不妨使用QSqlDatabase进行操作。2.实现代码下面是使用AxObject对ADO的封装/*File: ado.h 关于ADO的一些定义*/#ifndef ADO_H#define ADO_H#include #define adConnectUnspecified -1#define adStateClosed 0#define adOpenStatic 3#define adOpenDynamic 2#define adLockOptimistic 3#define adCmdText 1typedef long HRESULT;#define SUCCEEDED(hr) (HRESULT)(hr) = 0)#define FAILED(hr) (HRESULT)(hr) 0)#define ADO_DELETE(p) doif(p) delete (p); (p)=0;while(0)#endif / ADO_H/*File adoconnection.h AdoConnection的声明*/#ifndef ADOCONENCTION_H#define ADOCONENCTION_H#include #include class QTimer;class AdoConnection : public QObject Q_OBJECTpublic: explicit AdoConnection(QObject *parent = 0); bool open(const QString & connectString); bool open(); bool execute(const QString & sql); QVariant connection(); bool isOpen() const; void close();protected slots: void exception(int code, const QString & source, const QString & desc, const QString & help); void disconnect();private: QAxObject * object; QString openString; QTimer * timer;#endif / ADOCONENCTION_H/*File adoconnection.h AdoConnection的实现*/#include adoconenction.h#include ado.h#include #include AdoConnection:AdoConnection(QObject *parent) : QObject(parent) timer = new QTimer(this); Q_CHECK_PTR(timer); connect(timer,SIGNAL(timeout(),this,SLOT(disconnect(); object = new QAxObject(this); object-setControl(ADODB.Connection);/*创建ADODB.Connection对象*/ object-setProperty(ConnectionTimeout,300);/*设置超时时间，确保连接成功*/ connect(object,SIGNAL(exception(int,const QString&,const QString&,const QString &), this,SLOT(exception(int,const QString&,const QString&,const QString &);void AdoConnection:exception(int /*code*/, const QString & /*source*/, const QString & /*desc*/, const QString & /*help*/) /*输出异常或错误信息*/ qDebug() Code: code; qDebug() Source: source; qDebug() Description: desc; qDebug() Help: dynamicCall(Open(QString,QString,QString,int),connectString,adConnectUnspecified).toInt(); /*连接到数据库*/ return SUCCEEDED(hr);bool AdoConnection:open() if(openString.isEmpty() return false; bool ret = open(openString); if(timer & timer-isActive() timer-stop(); return ret;bool AdoConnection:execute(const QString & sql) if(!open() return false; /*执行SQL语句*/ HRESULT hr = object-dynamicCall(Execute(QString),sql).toInt(); return SUCCEEDED(hr);void AdoConnection:disconnect() if(isOpen() object-dynamicCall(Close); /*关闭数据库连接*/ if(timer) timer-stop(); /qDebug() isActive() timer-stop(); timer-start(5000); else disconnect();QVariant AdoConnection:connection() return object-asVariant();bool AdoConnection:isOpen() const return (bool)(object-property(State).toInt() != adStateClosed);/*File adorecordset.h AdoRecordset的实现*/#ifndef ADORECORDSET_H#define ADORECORDSET_H#include #include class QAxObject;class AdoConnection;class AdoRecordset : public QObject Q_OBJECTpublic: enum MoveAction First = 0, Next, Previous, Last ; AdoRecordset(const QVariant & dbConnection,QObject *parent = 0); AdoRecordset(AdoConnection * adoConnection,QObject *parent = 0); bool open(const QString & sql); void close(); bool next(); int recordCount() const; int fieldCount() const; QString fieldName(int index) const; QVariant fieldValue(int index) const;protected: bool move(MoveAction action);private: bool initial; QVariant dbConnection; QList fieldNames; QList fieldValues; QAxObject * object;#endif / ADORECORDSET_H/*File adorecordset.h AdoRecordset的实现*/#include adorecordset.h#include adoconenction.h#include ado.hAdoRecordset:AdoRecordset(const QVariant & connection,QObject *parent) : QObject(parent) , dbConnection(connection) object = new QAxObject(this); object-setControl(ADODB.Recordset);AdoRecordset:AdoRecordset(AdoConnection * adoConnection,QObject *parent) : QObject(parent) , dbConnection(adoConnection-connection() object = new QAxObject(this); object-setControl(ADODB.Recordset);bool AdoRecordset:open(const QString & sql) HRESULT hr = object-dynamicCall(Open(QString,QVariant,int,int,int),sql,dbConnection,adOpenStatic,adLockOptimistic,adCmdText).toInt(); initial = TRUE; return SUCCEEDED(hr);int AdoRecordset:recordCount() const return object-property(RecordCount).toUInt();bool AdoRecordset:next() bool ret = false; fieldNames.clear(); fieldValues.clear(); if(object-property(RecordCount).toInt() property(EOF).toBool() return false; QAxObject * adoFields = object-querySubObject(Fields); if(adoFields) int count = adoFields-property(Count).toInt(); for(int i = 0; i querySubObject(Item(int),i); if(adoField) fieldNames += adoField-property(Name).toString(); fieldValues += adoField-property(Value); ADO_DELETE(adoField); ADO_DELETE(adoFields); return ret;bool AdoRecordset:move(MoveAction action) static const char * actions = MoveFirst(void), MoveNext(void), MovePrevious(void), MoveLast(void) ; HRESULT hr = object-dynamicCall(actionsaction).toInt(); return SUCCEEDED(hr);int AdoRecordset:fieldCount() const return fieldNames.count();QString AdoRecordset:fieldName(int index) const if(index = fieldNames.count() return QString:null; return fieldNamesindex;QVariant AdoRecordset:fieldValue(int index) const if(index = fieldValues.count() return QVariant(); return fieldValuesindex;void AdoRecordset:close() objec