环境准备

在开始之前，请确保你已经安装了Python和PostgreSQL数据库。为了能够从Python连接到PostgreSQL，你需要安装psycopg2库。可以通过以下命令安装：

pip install psycopg2
#如果报错，安装下面这个
pip install psycopg2-binary

连接到PostgreSQL数据库

在进行数据写入之前，我们需要建立与PostgreSQL数据库的连接。以下是连接数据库的基本代码：

import psycopg2
from psycopg2 import Error

def create_connection():
    """创建数据库连接"""
    try:
        connection = psycopg2.connect(
            host="localhost",
            database="your_database_name",  # 替换为你的数据库名
            user="your_username",           # 替换为你的用户名
            password="your_password"        # 替换为你的密码
        )
        print("PostgreSQL Database connection successful")
        return connection
    except Error as e:
        print(f"The error '{e}' occurred")
        return None

插入数据

一旦建立了连接，我们就可以开始插入数据了。以下是一个插入数据的例子，假设我们有一个名为employees的表，我们想要向其中插入员工信息：

def insert_employee(conn, employee):
    """插入员工信息到数据库"""
    query = "INSERT INTO employees (name, position, department) VALUES (%s, %s, %s)"
    cursor = conn.cursor()
    try:
        cursor.execute(query, employee)
        conn.commit()  # 提交事务
        print("Employee inserted successfully")
    except Error as e:
        print(f"The error '{e}' occurred")
    finally:
        cursor.close()

# 插入数据的示例
employee = ('John Doe', 'Software Engineer', 'Development')
conn = create_connection()
if conn is not None:
    insert_employee(conn, employee)
    conn.close()

批量插入数据

在实际应用中，我们可能需要批量插入多条数据。以下是批量插入数据的示例：

def insert_employees(conn, employees):
    """批量插入员工信息"""
    query = "INSERT INTO employees (name, position, department) VALUES (%s, %s, %s)"
    cursor = conn.cursor()
    try:
        for employee in employees:
            cursor.execute(query, employee)
        conn.commit()  # 提交事务
        print("Employees inserted successfully")
    except Error as e:
        print(f"The error '{e}' occurred")
    finally:
        cursor.close()

# 批量插入数据的示例
employees = [
    ('Jane Doe', 'Project Manager', 'Development'),
    ('Alice Johnson', 'Data Analyst', 'Analytics'),
    ('Mike Smith', 'UX Designer', 'Design')
]
conn = create_connection()
if conn is not None:
    insert_employees(conn, employees)
    conn.close()

完整代码

以下是整合了上述例子的完整Python脚本，用于连接PostgreSQL数据库并执行数据插入操作：

import psycopg2
from psycopg2 import Error

# 创建数据库连接
def create_connection():
    """创建数据库连接"""
    try:
        connection = psycopg2.connect(
            host="localhost",
            database="your_database_name",  # 替换为你的数据库名
            user="your_username",           # 替换为你的用户名
            password="your_password"        # 替换为你的密码
        )
        print("PostgreSQL Database connection successful")
        return connection
    except Error as e:
        print(f"The error '{e}' occurred")
        return None

# 插入员工信息到数据库
def insert_employee(conn, employee):
    """插入员工信息"""
    query = "INSERT INTO employees (name, position, department) VALUES (%s, %s, %s)"
    cursor = conn.cursor()
    try:
        cursor.execute(query, employee)
        conn.commit()  # 提交事务
        print("Employee inserted successfully")
    except Error as e:
        print(f"The error '{e}' occurred")
    finally:
        cursor.close()

# 批量插入员工信息
def insert_employees(conn, employees):
    """批量插入员工信息"""
    query = "INSERT INTO employees (name, position, department) VALUES (%s, %s, %s)"
    cursor = conn.cursor()
    try:
        for employee in employees:
            cursor.execute(query, employee)
        conn.commit()  # 提交事务
        print("Employees inserted successfully")
    except Error as e:
        print(f"The error '{e}' occurred")
    finally:
        cursor.close()

# 主程序
if __name__ == '__main__':
    # 插入单条数据
    employee = ('John Doe', 'Software Engineer', 'Development')
    conn = create_connection()
    if conn is not None:
        insert_employee(conn, employee)
        conn.close()
    
    # 批量插入数据
    employees = [
        ('Jane Doe', 'Project Manager', 'Development'),
        ('Alice Johnson', 'Data Analyst', 'Analytics'),
        ('Mike Smith', 'UX Designer', 'Design')
    ]
    conn = create_connection()
    if conn is not None:
        insert_employees(conn, employees)
        conn.close()

在运行这段代码之前，请确保你已经替换了create_connection函数中的database、user和password的值，使其与你自己的PostgreSQL数据库配置相匹配。同时，确保你的PostgreSQL服务正在运行，并且employees表存在于你的数据库中，且表结构包含name、position和department这三个字段。

这段代码首先尝试连接到PostgreSQL数据库，然后执行插入操作来向employees表插入一条员工记录，并提交事务。接着，它尝试批量插入多条员工记录，并提交事务。最后，代码会关闭数据库连接。如果在任何步骤中遇到错误，它会打印错误信息。