c++ ado封装sqlserver实现增删查改

以下是使用 C++ 和 ADO 封装 SQL Server 实现增删查改的示例代码：

#include <iostream>
#include <string>
#include <Windows.h>
#import "C:\Program Files\Common Files\System\ado\msado15.dll" no_namespace rename("EOF", "adoEOF")

using namespace std;

class Database {
private:
    _ConnectionPtr conn;  // ADO 连接对象

public:
    // 构造函数，连接数据库
    Database(string server, string database, string username, string password) {
        try {
            conn.CreateInstance(__uuidof(Connection));
            conn->ConnectionString = "Provider=SQLOLEDB.1;Data Source=" + server + ";Initial Catalog=" + database + ";User ID=" + username + ";Password=" + password + ";";
            conn->Open("", "", "", adConnectUnspecified);
        }
        catch (_com_error e) {
            cerr << "Connect to database failed: " << e.ErrorMessage() << endl;
            exit(1);
        }
    }

    // 析构函数，关闭连接
    ~Database() {
        conn->Close();
    }

    // 执行查询语句，并返回查询结果集
    _RecordsetPtr query(string sql) {
        _RecordsetPtr rs;  // ADO 记录集对象

        try {
            rs.CreateInstance(__uuidof(Recordset));
            rs->Open(sql.c_str(), conn.GetInterfacePtr(), adOpenStatic, adLockOptimistic, adCmdText);
        }
        catch (_com_error e) {
            cerr << "Query failed: " << e.ErrorMessage() << endl;
            exit(1);
        }

        return rs;
    }

    // 执行增、删、改语句，并返回受影响的行数
    int execute(string sql) {
        int rows = 0;  // 受影响的行数

        try {
            _variant_t rowsAffected;
            conn->Execute(sql.c_str(), &rowsAffected, adExecuteNoRecords);
            rows = rowsAffected.intVal;
        }
        catch (_com_error e) {
            cerr << "Execute failed: " << e.ErrorMessage() << endl;
            exit(1);
        }

        return rows;
    }
};

int main() {
    // 连接数据库
    Database db("localhost", "test", "sa", "123456");

    // 查询数据
    _RecordsetPtr rs = db.query("SELECT * FROM users");
    while (!rs->adoEOF) {
        cout << rs->Fields->GetItem("id")->Value.intVal << ", " << (char*)(_bstr_t)rs->Fields->GetItem("name")->Value << ", " << rs->Fields->GetItem("age")->Value.intVal << endl;
        rs->MoveNext();
    }

    // 插入数据
    int rows = db.execute("INSERT INTO users (name, age) VALUES ('Tom', 18)");
    cout << "Inserted " << rows << " rows." << endl;

    // 更新数据
    rows = db.execute("UPDATE users SET age = 20 WHERE name = 'Tom'");
    cout << "Updated " << rows << " rows." << endl;

    // 删除数据
    rows = db.execute("DELETE FROM users WHERE name = 'Tom'");
    cout << "Deleted " << rows << " rows." << endl;

    return 0;
}

注意，在运行该示例代码前，需要先安装 Microsoft ActiveX Data Objects（ADO）库，并将 `msado15.dll` 文件路径修改为本地安装路径。另外，示例代码仅供参考，实际使用时需要根据具体情况进行调整。