How to handle database connections and operations using C++?

在C++中使用Data Access Objects (DAO) 库连接和操作数据库，包括建立数据库连接、执行SQL查询、插入新记录和更新现有记录。具体步骤为：1. 包含必要的库语句；2. 打开数据库文件；3. 创建Recordset对象执行SQL查询或操作数据；4. 遍历结果或按照具体需求更新记录。

如何在C++中进行数据库连接和操作

C++能够使用不同的库来连接和操作数据库，最常用的库是[Data Access Objects (DAO) Library](https://docs.microsoft.com/en-us/cpp/win32/data-access-objects-library?view=msvc-170)。

建立数据库连接

#include <dao.h>

int main()
{
    try
    {
        // 打开数据库文件
        Database db("mydb.mdb");

        // or
        Database db(L"c:\\mydb\\mydb.mdb", DB_SHARED_DENY);

        return 0;
    }
    catch (const DatabaseException& e)
    {
        std::cerr << "Error connecting to the database: " << e.what() << std::endl;
        return 1;
    }
}

执行SQL查询

#include <dao.h>

int main()
{
    try
    {
        // 打开数据库文件
        Database db("mydb.mdb");

        // 创建一个Recordset对象来执行SQL查询
        Recordset rs = db.OpenRecordset("SELECT * FROM Customers");

        // 遍历并打印结果
        while (!rs.IsEOF())
        {
            std::cout << "Customer ID: " << rs("CustomerID").lVal << std::endl;
            std::cout << "Customer Name: " << rs("CustomerName").StringValue << std::endl;
            std::cout << "Customer Email: " << rs("CustomerEmail").StringValue << std::endl;

            rs.MoveNext();
        }

        return 0;
    }
    catch (const DatabaseException& e)
    {
        std::cerr << "Error executing SQL query: " << e.what() << std::endl;
        return 1;
    }
}

插入新记录

#include <dao.h>

int main()
{
    try
    {
        // 打开数据库文件
        Database db("mydb.mdb");

        // 创建一个Recordset对象来插入新记录
        Recordset rs = db.OpenRecordset("Customers");

        rs.AddNew();
        rs("CustomerID") = 4;
        rs("CustomerName") = "New Customer";
        rs("CustomerEmail") = "new-customer@email.com";

        // 更新记录
        rs.Update();

        return 0;
    }
    catch (const DatabaseException& e)
    {
        std::cerr << "Error inserting new record: " << e.what() << std::endl;
        return 1;
    }
}

更新现有记录

#include <dao.h>

int main()
{
    try
    {
        // 打开数据库文件
        Database db("mydb.mdb");

        // 创建一个Recordset对象来执行SQL查询
        Recordset rs = db.OpenRecordset("SELECT * FROM Customers WHERE CustomerID = 4");

        // 更新记录
        if (!rs.IsEOF())
        {
            rs.Edit();
            rs("CustomerEmail") = "updated-new-customer@email.com";
            rs.Update();
        }

        return 0;
    }
    catch (const DatabaseException& e)
    {
        std::cerr << "Error updating existing record: " << e.what() << std::endl;
        return 1;
    }
}

The above is the detailed content of How to handle database connections and operations using C++?. For more information, please follow other related articles on the PHP Chinese website!