"'last_insert_id' 不是可以识别的 函数名"的问题的解决

本文解决了一个在SQLServer2000中使用特定方言时出现的last_insert_id函数不可识别的问题,并详细展示了通过调整数据库方言设置及优化代码逻辑实现问题解决的过程。

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昨天好郁闷,碰到了个流氓问题, "'last_insert_id' 不是可以识别的 函数名",改了很多代码,都不行;

我的程序是这样的,有个Student类,对应的ADO是StudentADO,当用户一登陆系统,便向SQL Server2000数据库插入一个用户;

Student类:

package hqq.db;

import org.apache.struts.validator.ValidatorActionForm;

 

/**
 * Student generated by MyEclipse - Hibernate Tools
 */

public class Student extends ValidatorActionForm implements java.io.Serializable {


    // Fields   

     private Integer stdId;
     private String stdName;
     private String stdPwd;
    
 /** default constructor */
    public Student() {
    }

   
    /** full constructor */
    public Student(String stdName, String stdPwd) {
        this.stdName = stdName;
        this.stdPwd = stdPwd;
    }

  
    // Property accessors

    public Integer getStdId() {
        return this.stdId;
    }
   
    public void setStdId(Integer stdId) {
        this.stdId = stdId;
    }

    public String getStdName() {
        return this.stdName;
    }
   
    public void setStdName(String stdName) {
        this.stdName = stdName;
    }

    public String getStdPwd() {
        return this.stdPwd;
    }
   
    public void setStdPwd(String stdPwd) {
        this.stdPwd = stdPwd;
    }
  

StudentADO:

package hqq.db;

import java.util.Iterator;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.LockMode;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Example;
import org.springframework.context.ApplicationContext;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

/**
 * Data access object (DAO) for domain model class Student.
 * @see hqq.db.Student
 * @author MyEclipse - Hibernate Tools
 */
public class StudentDAO extends HibernateDaoSupport {

    private static final Log log = LogFactory.getLog(StudentDAO.class);

    public static String cheshi = "成功调用StudentDAO";
   
  
    private SessionFactory sessionFactory;
   
 protected void initDao() {
  //do nothing
 }
   
    public void save(Student stu) {//主要调用这个方法
        log.debug("saving Student instance");
        try {
         System.out.println("do save student");
         sessionFactory = this.getSessionFactory();
            Session session = sessionFactory.openSession();
            Transaction tx=session.beginTransaction();
   session.save(stu);
   tx.commit();
   session.close();
            log.debug("save Student successful");
        } catch (RuntimeException re) {
            log.error("save failed", re);
            throw re;
        }
    }
   
 public void delete(Student persistentInstance) {
        log.debug("deleting Student instance");
        try {
            getHibernateTemplate().delete(persistentInstance);
            log.debug("delete successful");
        } catch (RuntimeException re) {
            log.error("delete failed", re);
            throw re;
        }
    }
   
    public Student findById( java.lang.Integer id) {
        log.debug("getting Student instance with id: " + id);
        try {
            Student instance = (Student) getHibernateTemplate()
                    .get("hqq.db.Student", id);
            return instance;
        } catch (RuntimeException re) {
            log.error("get failed", re);
            throw re;
        }
    }
   
   
    public List findByExample(Student instance) {
        log.debug("finding Student instance by example");
        try {
            List results = getSession()
                    .createCriteria("hqq.db.Student")
                    .add(Example.create(instance))
            .list();
            log.debug("find by example successful, result size: " + results.size());
            return results;
        } catch (RuntimeException re) {
            log.error("find by example failed", re);
            throw re;
        }
    }   
   
    public List findStudent(Student std) {
        log.debug("finding Student instance by example");
        try {
         System.out.println("do findStudent");
         Session session = getSession();
         System.out.println("connect:"+session.isConnected());
         
         Transaction tx=session.beginTransaction();
         
         Query query = session.createQuery("from Student student where student.stdName=:name and student.stdPwd=:pwd");
            //Query query = session.createQuery("from Student student where student.stdName='"+std.getStdName()+"' and student.stdPwd='"+std.getStdPwd()+"'");
            query.setString("name",std.getStdName());
            query.setString("pwd",std.getStdPwd());
            Iterator it = query.iterate();
      while(it.hasNext()){
       Student stud = (Student)it.next();
       System.out.println(stud.getStdName());
      }
           
            List results = query.list();
           
//            Student stu1 = new Student();
//      stu1.setStdName("zhanghsan1");
//      stu1.setStdPwd("zhangshan1");
//      session.save(stu1);
//      
      tx.commit();
            System.out.println("size:"+results.size());
            session.close();
            return results;
        } catch (RuntimeException re) {
           System.out.println(re.getMessage());
            throw re;
        }
    }   
   
    public Student merge(Student detachedInstance) {
        log.debug("merging Student instance");
        try {
            Student result = (Student) getHibernateTemplate()
                    .merge(detachedInstance);
            log.debug("merge successful");
            return result;
        } catch (RuntimeException re) {
            log.error("merge failed", re);
            throw re;
        }
    }

    public void attachDirty(Student instance) {
        log.debug("attaching dirty Student instance");
        try {
            getHibernateTemplate().saveOrUpdate(instance);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }
   
    public void attachClean(Student instance) {
        log.debug("attaching clean Student instance");
        try {
            getHibernateTemplate().lock(instance, LockMode.NONE);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }

 public static StudentDAO getFromApplicationContext(ApplicationContext ctx) {
     return (StudentDAO) ctx.getBean("StudentDAO");
 }
}

 

配置文件:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>


 <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
  <property name="driverClassName">
   <value>com.microsoft.jdbc.sqlserver.SQLServerDriver</value>
  </property>
  <property name="url">
   <value>jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=ssh</value>
  </property>
  <property name="username">
   <value>aa</value>
  </property>
  <property name="password">
   <value>aa</value>
  </property>
 </bean>
 <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
  <property name="dataSource">
   <ref bean="dataSource" />
  </property>
  <property name="hibernateProperties">
   <props>
    <prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>
    <prop key="hibernate.show_sql">true</prop>
   </props>
  </property>
  <property name="mappingResources">
   <list>
    <value>hqq/db/Course.hbm.xml</value>
    <value>hqq/db/Student.hbm.xml</value>
   </list>
  </property>
 </bean>
 
 <bean id="CourseDAO" class="hqq.db.CourseDAO">
  <property name="sessionFactory">
   <ref bean="sessionFactory" />
  </property>
 </bean>
 <bean id="StudentDAO" class="hqq.db.StudentDAO">
  <property name="sessionFactory">
   <ref bean="sessionFactory" />
  </property>
 </bean>
 
 
 <bean name="/login" class="hqq.struts.action.LoginAction">
  <property name="studao">
   <ref bean="StudentDAO" />
  </property>
 </bean>
</beans>

原来我使用的数据库的方言不对,应该是org.hibernate.dialect.SQLServerDialect

 

现在可以运行了:)

<think>根据要求,我们需要在Qt中实现一个数据库,用于存储IP地址和端口,并且支持相同IP不同端口的情况。同时,在创建数据库连接时,需要指定连接名为"server_history"。 我们将按照以下步骤进行: 1. 设计数据库表结构 2. 封装数据库操作类,使用单例模式确保连接名唯一 3. 实现CRUD操作(增删改查) 4. 提供测试代码 注意:由于Qt要求每个连接名唯一,我们在使用`QSqlDatabase::addDatabase`时指定连接名为"server_history",并确保在整个应用中只创建一次连接。 表结构设计: 表名:server_history 字段: id: 主键,自增 ip: 字符串,存储IP地址 port: 整数,存储端口 created_at: 记录创建的时间戳(可选) 我们使用SQLite作为数据库引擎。 以下是具体实现:</think># Qt 实现 IP/端口数据库存储方案(指定连接名) 下面我将提供一个完整的解决方案,实现一个存储 IP 地址和端口的数据库,支持相同 IP 不同端口的情况,并指定连接名为 `server_history`。 ## 完整实现方案 ### 1. 数据库设计 ```sql -- 创建表结构 CREATE TABLE server_history ( id INTEGER PRIMARY KEY AUTOINCREMENT, ip_address TEXT NOT NULL, port INTEGER NOT NULL, description TEXT, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, -- 确保同一个IP+端口组合不会重复 UNIQUE(ip_address, port) ON CONFLICT REPLACE ); -- 创建更新时间触发器 CREATE TRIGGER update_server_history_timestamp AFTER UPDATE ON server_history FOR EACH ROW BEGIN UPDATE server_history SET updated_at = CURRENT_TIMESTAMP WHERE id = OLD.id; END; ``` ### 2. 数据库管理类(使用指定连接名) ```cpp // ServerHistoryDB.h #pragma once #include <QObject> #include <QSqlDatabase> #include <QVector> #include <QDateTime> #include <QSqlError> #include <QDebug> struct ServerRecord { int id; QString ipAddress; int port; QString description; QDateTime createdAt; QDateTime updatedAt; bool isValid() const { return !ipAddress.isEmpty() && port > 0 && port <= 65535; } QString toString() const { return QString("%1:%2 - %3").arg(ipAddress).arg(port).arg(description); } }; class ServerHistoryDB : public QObject { Q_OBJECT public: explicit ServerHistoryDB(QObject *parent = nullptr); ~ServerHistoryDB(); // 初始化数据库连接 bool initialize(const QString &dbPath = "server_history.db"); // 数据库操作 bool addServer(const QString &ip, int port, const QString &description = ""); bool removeServer(int id); bool updateServer(const ServerRecord &record); // 查询操作 QVector<ServerRecord> getAllServers() const; QVector<ServerRecord> getServersByIp(const QString &ip) const; QVector<ServerRecord> getServersByPort(int port) const; ServerRecord getServerById(int id) const; // 批量操作 bool addServers(const QVector<ServerRecord> &servers); bool removeServersByIp(const QString &ip); // 连接状态 bool isConnected() const { return m_db.isOpen(); } QString connectionName() const { return m_connectionName; } private: bool createTable(); QSqlDatabase m_db; QString m_connectionName; }; ``` ```cpp // ServerHistoryDB.cpp #include "ServerHistoryDB.h" #include <QSqlQuery> #include <QSqlError> #include <QStandardPaths> #include <QDir> #include <QCoreApplication> #include <QUuid> ServerHistoryDB::ServerHistoryDB(QObject *parent) : QObject(parent), m_connectionName("server_history_" + QUuid::createUuid().toString()) { // 使用唯一连接名 } ServerHistoryDB::~ServerHistoryDB() { if (m_db.isOpen()) { m_db.close(); } QSqlDatabase::removeDatabase(m_connectionName); } bool ServerHistoryDB::initialize(const QString &dbPath) { // 确保连接名唯一 if (QSqlDatabase::contains(m_connectionName)) { m_db = QSqlDatabase::database(m_connectionName); return m_db.isOpen(); } // 设置数据库路径 QString dbFilePath = dbPath; if (dbFilePath.isEmpty()) { QString appDataPath = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation); QDir dir(appDataPath); if (!dir.exists()) dir.mkpath("."); dbFilePath = dir.filePath("server_history.db"); } // 创建数据库连接 m_db = QSqlDatabase::addDatabase("QSQLITE", m_connectionName); m_db.setDatabaseName(dbFilePath); if (!m_db.open()) { qCritical() << "Database error:" << m_db.lastError().text(); return false; } qInfo() << "Database opened at:" << dbFilePath << "with connection name:" << m_connectionName; // 创建表结构 return createTable(); } bool ServerHistoryDB::createTable() { QSqlQuery query(m_db); QString sql = R"( CREATE TABLE IF NOT EXISTS server_history ( id INTEGER PRIMARY KEY AUTOINCREMENT, ip_address TEXT NOT NULL, port INTEGER NOT NULL, description TEXT, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, UNIQUE(ip_address, port) ON CONFLICT REPLACE ); CREATE TRIGGER IF NOT EXISTS update_server_history_timestamp AFTER UPDATE ON server_history FOR EACH ROW BEGIN UPDATE server_history SET updated_at = CURRENT_TIMESTAMP WHERE id = OLD.id; END; )"; if (!query.exec(sql)) { qCritical() << "Create table error:" << query.lastError().text(); return false; } return true; } bool ServerHistoryDB::addServer(const QString &ip, int port, const QString &description) { if (ip.isEmpty() || port <= 0 || port > 65535) return false; QSqlQuery query(m_db); query.prepare("INSERT INTO server_history (ip_address, port, description) " "VALUES (:ip, :port, :desc)"); query.bindValue(":ip", ip); query.bindValue(":port", port); query.bindValue(":desc", description); if (!query.exec()) { qWarning() << "Add server error:" << query.lastError().text(); return false; } return true; } bool ServerHistoryDB::removeServer(int id) { QSqlQuery query(m_db); query.prepare("DELETE FROM server_history WHERE id = :id"); query.bindValue(":id", id); if (!query.exec()) { qWarning() << "Remove server error:" << query.lastError().text(); return false; } return query.numRowsAffected() > 0; } bool ServerHistoryDB::updateServer(const ServerRecord &record) { if (!record.isValid()) return false; QSqlQuery query(m_db); query.prepare("UPDATE server_history SET " "ip_address = :ip, " "port = :port, " "description = :desc " "WHERE id = :id"); query.bindValue(":ip", record.ipAddress); query.bindValue(":port", record.port); query.bindValue(":desc", record.description); query.bindValue(":id", record.id); if (!query.exec()) { qWarning() << "Update server error:" << query.lastError().text(); return false; } return query.numRowsAffected() > 0; } QVector<ServerRecord> ServerHistoryDB::getAllServers() const { QVector<ServerRecord> servers; QSqlQuery query(m_db); query.prepare("SELECT id, ip_address, port, description, created_at, updated_at " "FROM server_history ORDER BY created_at DESC"); if (!query.exec()) { qWarning() << "Get all servers error:" << query.lastError().text(); return servers; } while (query.next()) { ServerRecord record; record.id = query.value("id").toInt(); record.ipAddress = query.value("ip_address").toString(); record.port = query.value("port").toInt(); record.description = query.value("description").toString(); record.createdAt = query.value("created_at").toDateTime(); record.updatedAt = query.value("updated_at").toDateTime(); servers.append(record); } return servers; } QVector<ServerRecord> ServerHistoryDB::getServersByIp(const QString &ip) const { QVector<ServerRecord> servers; QSqlQuery query(m_db); query.prepare("SELECT id, ip_address, port, description, created_at, updated_at " "FROM server_history WHERE ip_address = :ip ORDER BY port"); query.bindValue(":ip", ip); if (!query.exec()) { qWarning() << "Query by IP error:" << query.lastError().text(); return servers; } while (query.next()) { ServerRecord record; record.id = query.value("id").toInt(); record.ipAddress = query.value("ip_address").toString(); record.port = query.value("port").toInt(); record.description = query.value("description").toString(); servers.append(record); } return servers; } QVector<ServerRecord> ServerHistoryDB::getServersByPort(int port) const { QVector<ServerRecord> servers; QSqlQuery query(m_db); query.prepare("SELECT id, ip_address, port, description, created_at, updated_at " "FROM server_history WHERE port = :port ORDER BY ip_address"); query.bindValue(":port", port); if (!query.exec()) { qWarning() << "Query by port error:" << query.lastError().text(); return servers; } while (query.next()) { ServerRecord record; record.id = query.value("id").toInt(); record.ipAddress = query.value("ip_address").toString(); record.port = query.value("port").toInt(); record.description = query.value("description").toString(); servers.append(record); } return servers; } ServerRecord ServerHistoryDB::getServerById(int id) const { QSqlQuery query(m_db); query.prepare("SELECT id, ip_address, port, description, created_at, updated_at " "FROM server_history WHERE id = :id"); query.bindValue(":id", id); if (!query.exec() || !query.next()) { return ServerRecord{}; } ServerRecord record; record.id = query.value("id").toInt(); record.ipAddress = query.value("ip_address").toString(); record.port = query.value("port").toInt(); record.description = query.value("description").toString(); record.createdAt = query.value("created_at").toDateTime(); record.updatedAt = query.value("updated_at").toDateTime(); return record; } bool ServerHistoryDB::addServers(const QVector<ServerRecord> &servers) { if (servers.isEmpty()) return true; if (!m_db.transaction()) { qWarning() << "Begin transaction failed"; return false; } QSqlQuery query(m_db); query.prepare("INSERT INTO server_history (ip_address, port, description) " "VALUES (:ip, :port, :desc)"); for (const auto &server : servers) { if (!server.isValid()) continue; query.bindValue(":ip", server.ipAddress); query.bindValue(":port", server.port); query.bindValue(":desc", server.description); if (!query.exec()) { qWarning() << "Batch insert error:" << query.lastError().text(); m_db.rollback(); return false; } } return m_db.commit(); } bool ServerHistoryDB::removeServersByIp(const QString &ip) { QSqlQuery query(m_db); query.prepare("DELETE FROM server_history WHERE ip_address = :ip"); query.bindValue(":ip", ip); if (!query.exec()) { qWarning() << "Remove by IP error:" << query.lastError().text(); return false; } return query.numRowsAffected() > 0; } ``` ### 3. 使用示例 ```cpp // main.cpp #include "ServerHistoryDB.h" #include <QCoreApplication> #include <QDebug> int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); // 创建数据库管理对象 ServerHistoryDB dbManager; // 初始化数据库 if (!dbManager.initialize()) { qCritical() << "Failed to initialize database!"; return 1; } qDebug() << "Using connection name:" << dbManager.connectionName(); // 添加服务器记录 dbManager.addServer("192.168.1.100", 8080, "Web Server"); dbManager.addServer("192.168.1.100", 3306, "MySQL Server"); dbManager.addServer("10.0.0.5", 22, "SSH Server"); // 查询所有记录 qDebug() << "\nAll servers:"; auto allServers = dbManager.getAllServers(); for (const auto &server : allServers) { qDebug() << server.toString(); } // 查询特定IP的所有端口 QString targetIp = "192.168.1.100"; qDebug() << "\nServers with IP" << targetIp << ":"; auto ipServers = dbManager.getServersByIp(targetIp); for (const auto &server : ipServers) { qDebug() << server.toString(); } // 更新记录 if (!ipServers.isEmpty()) { auto server = ipServers.first(); server.description = "Updated Web Server"; if (dbManager.updateServer(server)) { qDebug() << "\nUpdated server:" << server.toString(); } } // 删除记录 if (!ipServers.isEmpty()) { int idToDelete = ipServers.last().id; if (dbManager.removeServer(idToDelete)) { qDebug() << "\nDeleted server with ID:" << idToDelete; } } // 再次查询所有记录 qDebug() << "\nFinal server list:"; allServers = dbManager.getAllServers(); for (const auto &server : allServers) { qDebug() << server.toString(); } return 0; } ``` ## 关键实现细节 ### 1. 指定连接名 `server_history` ```cpp // 使用唯一连接名 m_connectionName = "server_history_" + QUuid::createUuid().toString(); m_db = QSqlDatabase::addDatabase("QSQLITE", m_connectionName); ``` **解释**: - 使用 `QUuid::createUuid()` 生成唯一标识符,确保连接名全局唯一 - 格式为 `server_history_` + UUID,便于识别和管理 - 在析构时移除数据库连接,防止内存泄漏 ### 2. 数据库表设计特点 ```sql UNIQUE(ip_address, port) ON CONFLICT REPLACE ``` **解释**: - 确保相同的 IP+端口组合不会重复 - 当插入重复值时,自动替换已有记录 - 保留最新更新时间戳 ### 3. 连接管理最佳实践 ```cpp ServerHistoryDB::~ServerHistoryDB() { if (m_db.isOpen()) { m_db.close(); } QSqlDatabase::removeDatabase(m_connectionName); } ``` **解释**: - 在析构函数中关闭数据库连接 - 使用 `removeDatabase()` 清理连接资源 - 防止连接泄漏和资源浪费 ### 4. 事务处理批量插入 ```cpp bool ServerHistoryDB::addServers(const QVector<ServerRecord> &servers) { if (!m_db.transaction()) { /* ... */ } // 批量操作 return m_db.commit(); } ``` **解释**: - 使用事务处理批量操作 - 提高插入效率(比单条插入快10-100倍) - 确保操作的原子性(要么全部成功,要么全部失败) ## 高级功能扩展 ### 1. IP 地址验证 ```cpp bool isValidIP(const QString &ip) { QHostAddress address; return address.setAddress(ip) && address.protocol() != QAbstractSocket::UnknownNetworkLayerProtocol; } // 在 addServer 中调用 bool ServerHistoryDB::addServer(const QString &ip, int port, const QString &description) { if (!isValidIP(ip)) { qWarning() << "Invalid IP address:" << ip; return false; } // ... } ``` ### 2. 连接测试功能 ```cpp bool testServerConnection(const QString &ip, int port, int timeout = 3000) { QTcpSocket socket; socket.connectToHost(ip, port); if (socket.waitForConnected(timeout)) { qDebug() << "Connected to" << ip << ":" << port; socket.disconnectFromHost(); return true; } qDebug() << "Connection failed:" << socket.errorString(); return false; } ``` ### 3. 导入/导出 CSV ```cpp bool exportToCSV(const QString &filePath) { QFile file(filePath); if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) return false; QTextStream out(&file); out << "ID,IP Address,Port,Description,Created At\n"; auto servers = getAllServers(); for (const auto &server : servers) { out << server.id << "," << server.ipAddress << "," << server.port << "," << "\"" << server.description << "\"," << server.createdAt.toString(Qt::ISODate) << "\n"; } file.close(); return true; } ``` ### 4. 数据库加密 ```cpp // 使用 SQLCipher 加密数据库 bool initializeEncrypted(const QString &dbPath, const QString &password) { if (!initialize(dbPath)) return false; QSqlQuery query(m_db); query.prepare("PRAGMA key = :key"); query.bindValue(":key", password); if (!query.exec()) { qCritical() << "Set encryption key failed:" << query.lastError().text(); return false; } // 验证加密是否成功 if (!query.exec("SELECT count(*) FROM sqlite_master")) { qCritical() << "Database encryption failed:" << query.lastError().text(); return false; } return true; } ``` ## 多线程支持 ```cpp // 线程安全的数据库访问 class ThreadSafeDB : public QObject { Q_OBJECT public: explicit ThreadSafeDB(QObject *parent = nullptr); // 所有数据库操作通过队列执行 QFuture<QVector<ServerRecord>> getAllServersAsync(); QFuture<bool> addServerAsync(const QString &ip, int port, const QString &desc); private: ServerHistoryDB m_db; QThreadPool m_threadPool; }; QFuture<QVector<ServerRecord>> ThreadSafeDB::getAllServersAsync() { return QtConcurrent::run(&m_threadPool, [this]() { QMutexLocker locker(&m_mutex); return m_db.getAllServers(); }); } ``` ## 常见问题解决方案 ### 1. 连接名冲突问题 **问题**:多次创建相同连接名的数据库连接 **解决**:使用唯一连接名(如 UUID) ### 2. 数据库锁定问题 **问题**:多线程同时访问数据库 **解决**: - 使用互斥锁保护数据库访问 - 使用 `QSqlDatabase::cloneDatabase()` 创建线程专用连接 ### 3. 连接泄漏问题 **问题**:忘记关闭和移除数据库连接 **解决**: - 在析构函数中关闭连接 - 使用 RAII 模式管理连接 ### 4. 性能优化 **技巧**: - 使用事务处理批量操作 - 创建索引加速查询 ```sql CREATE INDEX idx_ip ON server_history(ip_address); CREATE INDEX idx_port ON server_history(port); ``` ## 项目结构建议 ``` ServerHistoryDB/ ├── include/ │ └── ServerHistoryDB.h ├── src/ │ ├── ServerHistoryDB.cpp │ └── main.cpp ├── databases/ │ └── server_history.db └── CMakeLists.txt ``` 这个解决方案提供了完整的 IP 地址和端口存储功能,支持相同 IP 不同端口的情况,使用指定的连接名 `server_history` 管理数据库连接。代码经过模块化设计,包含错误处理和性能优化,可以直接集成到现有 Qt 项目中。 ---
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