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

3. 创建数据表

在执行增删改查前，建议先构建一张测试表。注意 SQL 语句中的引号匹配及缩进问题：

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()

if connection:
    create_table(connection)

4. 封装 CRUD 管理类

为了复用性更高，建议将数据库操作封装成一个类。这样既能统一管理连接状态，又能避免重复编写连接逻辑。

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

    def execute_query(self, sql, params=None):
        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):
        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

    # --- 业务方法示例 ---

    def insert_user(self, id, username, age):
        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):
        sql = "SELECT * FROM user_info ORDER BY id"
        return self.execute_query(sql)

    def select_user_by_id(self, id):
        sql = "SELECT * FROM user_info WHERE id = %s"
        return self.execute_query(sql, (id,))

    def update_user_age(self, id, new_age):
        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):
        sql = "DELETE FROM user_info WHERE id = %s"
        return self.execute_update(sql, (id,))

    def search_users_by_age_range(self, min_age, max_age):
        sql = "SELECT * FROM user_info WHERE age BETWEEN %s AND %s ORDER BY age"
        return self.execute_query(sql, (min_age, max_age))

5. 实战调用示例

有了上述管理类，实际业务中只需实例化对象并调用相应方法即可。以下是完整的操作流程演示：

if __name__ == "__main__":
    db_manager = KingbaseESManager(
        dbname="TEST",
        user="SYSTEM",
        password="qwe123!@#",
        host="127.0.0.1",
        port=54321
    )

    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)

        # 更新用户年龄
        print("\n更新张三的年龄为 26:")
        db_manager.update_user_age(1, 26)

        # 删除 ID 为 5 的用户
        print("\n删除 ID 为 5 的用户:")
        db_manager.delete_user(5)

        # 再次查询验证
        print("\n删除后的所有用户:")
        remaining_users = db_manager.select_all_users()
        for user in remaining_users:
            print(user)

        db_manager.disconnect()

通过这种方式，我们不仅完成了基础的数据交互，还建立了一套可复用的数据库操作框架。在实际项目中，只需修改连接参数和 SQL 逻辑，即可快速适配不同的业务需求。