c++ sqlserver 增删改查

好的，下面是一个简单的示例代码，演示如何使用C++封装ADO连接SQL Server进行增删查改操作： ```cpp #include <iostream> #include <windows.h> #include <comdef.h> #include <atlbase.h> #import "C:\Program Files\Common Files\System\ado\msado15.dll" no_namespace rename("EOF", "adoEOF") class CSQLServer { public: CSQLServer(); ~CSQLServer(); bool Connect(const std::string& strServer, const std::string& strDatabase, const std::string& strUser, const std::string& strPassword); void Disconnect(); bool ExecuteNonQuery(const std::string& strSQL); bool ExecuteScalar(const std::string& strSQL, _variant_t& vtResult); private: bool InitADO(); void UninitADO(); private: _ConnectionPtr m_pConnection; }; CSQLServer::CSQLServer() { InitADO(); } CSQLServer::~CSQLServer() { UninitADO(); } bool CSQLServer::Connect(const std::string& strServer, const std::string& strDatabase, const std::string& strUser, const std::string& strPassword) { try { std::string strConnString = "Provider=SQLOLEDB.1;"; strConnString += "Persist Security Info=False;"; strConnString += "Data Source=" + strServer + ";"; strConnString += "Initial Catalog=" + strDatabase + ";"; strConnString += "User ID=" + strUser + ";"; strConnString += "Password=" + strPassword + ";"; m_pConnection->Open(strConnString.c_str(), "", "", adConnectUnspecified); return true; } catch (_com_error& e) { std::cout << "Connect failed, error message: " << e.Description() << std::endl; return false; } } void CSQLServer::Disconnect() { m_pConnection->Close(); } bool CSQLServer::ExecuteNonQuery(const std::string& strSQL) { try { _RecordsetPtr pRecordset; pRecordset = m_pConnection->Execute(strSQL.c_str(), NULL, adCmdText); return true; } catch (_com_error& e) { std::cout << "ExecuteNonQuery failed, error message: " << e.Description() << std::endl; return false; } } bool CSQLServer::ExecuteScalar(const std::string& strSQL, _variant_t& vtResult) { try { _RecordsetPtr pRecordset; pRecordset = m_pConnection->Execute(strSQL.c_str(), NULL, adCmdText); if (pRecordset->adoEOF == true) { vtResult.Clear(); return false; } vtResult = pRecordset->Fields->GetItem((long)0)->Value; return true; } catch (_com_error& e) { std::cout << "ExecuteScalar failed, error message: " << e.Description() << std::endl; return false; } } bool CSQLServer::InitADO() { try { HRESULT hr = CoInitialize(NULL); if (FAILED(hr)) { std::cout << "CoInitialize failed" << std::endl; return false; } hr = m_pConnection.CreateInstance(__uuidof(Connection)); if (FAILED(hr)) { std::cout << "CreateInstance failed" << std::endl; CoUninitialize(); return false; } return true; } catch (_com_error& e) { std::cout << "InitADO failed, error message: " << e.Description() << std::endl; return false; } } void CSQLServer::UninitADO() { m_pConnection.Release(); CoUninitialize(); } int main() { CSQLServer sqlServer; if (!sqlServer.Connect("localhost", "MyDatabase", "sa", "123456")) { return 0; } // 插入数据 std::string strSQL = "INSERT INTO MyTable (Name, Age) VALUES ('Tom', 20)"; sqlServer.ExecuteNonQuery(strSQL); // 修改数据 strSQL = "UPDATE MyTable SET Age = 21 WHERE Name = 'Tom'"; sqlServer.ExecuteNonQuery(strSQL); // 查询数据 strSQL = "SELECT Age FROM MyTable WHERE Name = 'Tom'"; _variant_t vtResult; if (sqlServer.ExecuteScalar(strSQL, vtResult)) { std::cout << "Tom's age is " << (int)vtResult.intVal << std::endl; } else { std::cout << "Tom not found!" << std::endl; } // 删除数据 strSQL = "DELETE FROM MyTable WHERE Name = 'Tom'"; sqlServer.ExecuteNonQuery(strSQL); sqlServer.Disconnect(); return 0; } ``` 上述代码使用`CSQLServer`类封装了ADO连接SQL Server的操作，并提供了插入、修改、查询、删除数据的方法。在使用时，只需要创建一个`CSQLServer`对象，调用`Connect`方法连接数据库，然后调用相应的方法执行SQL语句即可。 注意：上述代码使用了`#import`指令引入了`msado15.dll`库，需要确保该库已经安装在您的系统中。另外，需要链接`comsupp.lib`库。

以下是一个简单的封装OCI的C++类，实现对Oracle数据库的增删改查操作。 ```c++ #include <iostream> #include <string> #include <oci.h> class OracleDB { public: OracleDB() : envhp(nullptr), errhp(nullptr), srvhp(nullptr), svchp(nullptr), stmthp(nullptr) {} ~OracleDB() { if (envhp) OCIHandleFree(envhp, OCI_HTYPE_ENV); if (errhp) OCIHandleFree(errhp, OCI_HTYPE_ERROR); if (srvhp) OCIHandleFree(srvhp, OCI_HTYPE_SERVER); if (svchp) OCIHandleFree(svchp, OCI_HTYPE_SVCCTX); if (stmthp) OCIHandleFree(stmthp, OCI_HTYPE_STMT); } bool connect(const std::string& user, const std::string& password, const std::string& db) { OCIEnvCreate(&envhp, OCI_THREADED, nullptr, nullptr, nullptr, nullptr, 0, nullptr); OCIHandleAlloc(envhp, (void**)&errhp, OCI_HTYPE_ERROR, 0, nullptr); OCIHandleAlloc(envhp, (void**)&srvhp, OCI_HTYPE_SERVER, 0, nullptr); OCIHandleAlloc(envhp, (void**)&svchp, OCI_HTYPE_SVCCTX, 0, nullptr); OCILogon2(envhp, errhp, &svchp, (const OraText*)user.c_str(), user.length(), (const OraText*)password.c_str(), password.length(), (const OraText*)db.c_str(), db.length(), OCI_DEFAULT); return true; } void disconnect() { OCILogoff(svchp, errhp); } bool execute(const std::string& sql) { OCIHandleAlloc(envhp, (void**)&stmthp, OCI_HTYPE_STMT, 0, nullptr); OCIStmtPrepare(stmthp, errhp, (const OraText*)sql.c_str(), sql.length(), OCI_NTV_SYNTAX, OCI_DEFAULT); OCIStmtExecute(svchp, stmthp, errhp, 1, 0, nullptr, nullptr, OCI_DEFAULT); return true; } int query(const std::string& sql) { OCIHandleAlloc(envhp, (void**)&stmthp, OCI_HTYPE_STMT, 0, nullptr); OCIStmtPrepare(stmthp, errhp, (const OraText*)sql.c_str(), sql.length(), OCI_NTV_SYNTAX, OCI_DEFAULT); OCIStmtExecute(svchp, stmthp, errhp, 0, 0, nullptr, nullptr, OCI_DEFAULT); int cols = 0; OCIAttrGet(stmthp, OCI_HTYPE_STMT, &cols, nullptr, OCI_ATTR_PARAM_COUNT, errhp); return cols; } private: OCIEnv* envhp; OCIError* errhp; OCIServer* srvhp; OCISvcCtx* svchp; OCIStmt* stmthp; }; int main() { OracleDB db; db.connect("user", "password", "db"); // 插入数据 db.execute("INSERT INTO table_name(col1, col2) VALUES('value1', 'value2')"); // 更新数据 db.execute("UPDATE table_name SET col1='new_value1' WHERE col2='value2'"); // 删除数据 db.execute("DELETE FROM table_name WHERE col1='new_value1'"); // 查询数据 int cols = db.query("SELECT * FROM table_name WHERE col2='value2'"); std::cout << "Number of columns: " << cols << std::endl; db.disconnect(); return 0; } ``` 这个类中，connect函数用于连接数据库；disconnect函数用于断开连接；execute函数用于执行insert、update、delete等操作；query函数用于执行select操作，并返回结果列数。这只是一个简单的实现，具体的实现方式可以根据实际需要进行调整。