Ubuntu 系统下 Python 连接 KingbaseES 数据库实现增删改查

创建一个 connect_database.py 把上面代码复制进去，然后执行：

python connect_database.py

3. 创建数据表

在执行增删改查操作前，需要先创建一张测试表，有表才好对后面的案例进行操作。

def create_table(conn):
    try:
        cursor = conn.cursor()
        create_table_sql = """ CREATE TABLE IF NOT EXISTS user_info (
            id INTEGER PRIMARY KEY,
            username VARCHAR(50) NOT NULL,
            age INTEGER,
            created_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        ) """
        cursor.execute(create_table_sql)
        conn.commit()
        cursor.close()
        print("表创建成功")
    except Exception as e:
        print(f"创建表失败：{e}")
        conn.rollback()

# 创建表
if connection:
    create_table(connection)

同理，在 ubuntu 服务器上新建一个 create_table.py 文件，把上面代码丢进去执行：

python create_table.py

4. 实现增删改查功能

4.1 新增

def insert_data_example():
    """插入数据示例"""
    db_manager = KingbaseESManager(
        dbname="test",
        user="SYSTEM",
        password="qwe123!@#",
        host="127.0.0.1",
        port="54321"
    )
    if db_manager.connect():
        # 插入单条数据
        insert_sql = "INSERT INTO user_info (id, username, age) VALUES (%s, %s, %s)"
        params = (1, '张三', 25)
        db_manager.execute_update(insert_sql, params)
        
        # 插入多条数据
        users_to_insert = [
            (2, '李四', 30),
            (3, '王五', 28),
            (4, '赵六', 35),
            (5, '钱七', 22)
        ]
        for user in users_to_insert:
            db_manager.execute_update(insert_sql, user)
        
        db_manager.disconnect()

# 执行插入数据
insert_data_example()

调用 python 后登录数据库查看是否已经插入数据库，ubuntu 登录如下所示：

# 切换到 kingbase 用户
su - kingbase
# 连接数据库
ksql -U SYSTEM -d test -p 54321
# 如果上面执行不成功，可以指定目录来连接
/kingbase/data/KESRealPro/V009R002C012/Server/bin/ksql -U SYSTEM -d test -p 54321

执行查询语句，查询所有用户数据，验证插入结果：

-- 查询所有用户数据，验证插入结果
SELECT * FROM user_info ORDER BY id;

4.2 查询

def query_data_example():
    """查询数据示例"""
    db_manager = KingbaseESManager(
        dbname="test",
        user="SYSTEM",
        password="qwe123!@#",
        host="127.0.0.1",
        port="54321"
    )
    if db_manager.connect():
        # 查询所有数据
        print("所有用户信息:")
        select_all_sql = "SELECT * FROM user_info ORDER BY id"
        all_users = db_manager.execute_query(select_all_sql)
        for user in all_users:
            print(user)
        
        # 根据 ID 查询特定用户
        print("\n查询 ID 为 2 的用户:")
        select_by_id_sql = "SELECT * FROM user_info WHERE id = %s"
        user_by_id = db_manager.execute_query(select_by_id_sql, (2,))
        print(user_by_id)
        
        # 根据年龄范围查询用户
        print("\n年龄在 25-30 岁之间的用户:")
        select_by_age_sql = "SELECT * FROM user_info WHERE age BETWEEN %s AND %s ORDER BY age"
        users_by_age = db_manager.execute_query(select_by_age_sql, (25, 30))
        for user in users_by_age:
            print(user)
        
        db_manager.disconnect()

# 执行查询数据
query_data_example()

4.3 修改

def update_data_example():
    """更新数据示例"""
    db_manager = KingbaseESManager(
        dbname="TEST",
        user="SYSTEM",
        password="your_password",
        host="127.0.0.1",
        port="54321"
    )
    if db_manager.connect():
        # 更新用户年龄
        print("更新张三的年龄为 26:")
        update_sql = "UPDATE user_info SET age = %s WHERE id = %s"
        db_manager.execute_update(update_sql, (26, 1))
        
        # 验证更新结果
        print("\n更新后的用户信息:")
        select_sql = "SELECT * FROM user_info WHERE id = %s"
        updated_user = db_manager.execute_query(select_sql, (1,))
        print(updated_user)
        
        db_manager.disconnect()

# 执行更新数据
update_data_example()

4.4 删除

def delete_data_example():
    """删除数据示例"""
    db_manager = KingbaseESManager(
        dbname="TEST",
        user="SYSTEM",
        password="your_password",
        host="127.0.0.1",
        port="54321"
    )
    if db_manager.connect():
        # 删除 ID 为 5 的用户
        print("删除 ID 为 5 的用户:")
        delete_sql = "DELETE FROM user_info WHERE id = %s"
        db_manager.execute_update(delete_sql, (5,))
        
        # 验证删除结果
        print("\n删除后的所有用户:")
        select_all_sql = "SELECT * FROM user_info ORDER BY id"
        remaining_users = db_manager.execute_query(select_all_sql)
        for user in remaining_users:
            print(user)
        
        db_manager.disconnect()

# 执行删除数据
delete_data_example()

4.5 封装一个类 CRUD 方便复用

下面将实现完整的增删改查功能，并将这些操作封装在一个类中，方便复用。

import ksycopg2
from datetime import datetime

class KingbaseESManager:
    def __init__(self, dbname, user, password, host, port):
        self.conn = None
        self.db_params = {
            "database": dbname,
            "user": user,
            "password": password,
            "host": host,
            "port": port
        }

    def connect(self):
        """连接数据库"""
        try:
            self.conn = ksycopg2.connect(**self.db_params)
            print("数据库连接成功")
            return True
        except Exception as e:
            print(f"连接数据库失败：{e}")
            return False

    def disconnect(self):
        """断开数据库连接"""
        if self.conn:
            self.conn.close()
            print("数据库连接已关闭")

    def execute_query(self, sql, params=None):
        """执行查询语句并返回结果"""
        try:
            cursor = self.conn.cursor()
            if params:
                cursor.execute(sql, params)
            else:
                cursor.execute(sql)
            results = cursor.fetchall()
            cursor.close()
            return results
        except Exception as e:
            print(f"查询执行失败：{e}")
            return None

    def execute_update(self, sql, params=None):
        """执行更新操作（插入、更新、删除）"""
        try:
            cursor = self.conn.cursor()
            if params:
                cursor.execute(sql, params)
            else:
                cursor.execute(sql)
            self.conn.commit()
            affected_rows = cursor.rowcount
            cursor.close()
            print(f"操作成功，影响行数：{affected_rows}")
            return affected_rows
        except Exception as e:
            self.conn.rollback()
            print(f"操作执行失败：{e}")
            return -1

    def insert_user(self, id, username, age):
        """插入用户数据"""
        sql = "INSERT INTO user_info (id, username, age) VALUES (%s, %s, %s)"
        params = (id, username, age)
        return self.execute_update(sql, params)

    def select_all_users(self):
        """查询所有用户"""
        sql = "SELECT * FROM user_info ORDER BY id"
        return self.execute_query(sql)

    def select_user_by_id(self, id):
        """根据 ID 查询用户"""
        sql = "SELECT * FROM user_info WHERE id = %s"
        params = (id,)
        return self.execute_query(sql, params)

    def update_user_age(self, id, new_age):
        """更新用户年龄"""
        sql = "UPDATE user_info SET age = %s WHERE id = %s"
        params = (new_age, id)
        return self.execute_update(sql, params)

    def delete_user(self, id):
        """删除用户"""
        sql = "DELETE FROM user_info WHERE id = %s"
        params = (id,)
        return self.execute_update(sql, params)

    def search_users_by_age_range(self, min_age, max_age):
        """根据年龄范围查询用户"""
        sql = "SELECT * FROM user_info WHERE age BETWEEN %s AND %s ORDER BY age"
        params = (min_age, max_age)
        return self.execute_query(sql, params)

# 使用示例
if __name__ == "__main__":
    # 创建数据库管理实例
    db_manager = KingbaseESManager(
        dbname="TEST",
        user="SYSTEM",
        password="qwe123!@#",
        host="127.0.0.1",
        port="54321"
    )
    
    # 连接数据库
    if db_manager.connect():
        # 插入多条用户数据
        users_to_insert = [
            (1, '张三', 25),
            (2, '李四', 30),
            (3, '王五', 28),
            (4, '赵六', 35),
            (5, '钱七', 22)
        ]
        for user in users_to_insert:
            db_manager.insert_user(*user)
        
        # 查询所有用户
        print("所有用户信息:")
        all_users = db_manager.select_all_users()
        for user in all_users:
            print(user)
        
        # 根据 ID 查询用户
        print("\n查询 ID 为 2 的用户:")
        user_by_id = db_manager.select_user_by_id(2)
        print(user_by_id)
        
        # 更新用户年龄
        print("\n更新张三的年龄为 26:")
        db_manager.update_user_age(1, 26)
        
        # 查询年龄在 25-30 岁之间的用户
        print("\n年龄在 25-30 岁之间的用户:")
        users_by_age = db_manager.search_users_by_age_range(25, 30)
        for user in users_by_age:
            print(user)
        
        # 删除 ID 为 5 的用户
        print("\n删除 ID 为 5 的用户:")
        db_manager.delete_user(5)
        
        # 再次查询所有用户
        print("\n删除后的所有用户:")
        remaining_users = db_manager.select_all_users()
        for user in remaining_users:
            print(user)
        
        # 断开连接
        db_manager.disconnect()

5.总结

本文介绍了在 Ubuntu 系统中使用 Python 连接国产金仓数据库 KingbaseES 的方法。主要内容包括：1.安装与 Python 版本匹配的 ksycopg2 驱动；2.配置环境变量和连接参数；3.实现数据库连接、建表及增删改查操作；4.封装可复用的数据库操作类。通过具体代码示例演示了数据插入、查询、更新和删除等常见操作，并提供了验证方法。文章还分享了环境配置中的常见问题和解决方案，帮助开发者快速上手 KingbaseES 数据库操作。