图片怎么写入与读出数据库

要将图片写入数据库，你需要将其转换为二进制格式并将其存储在数据库的BLOB字段中。可以使用Python的Pillow库来打开、读取和转换图像文件。以下是将一张名为“image.png”的图片写入数据库的示例代码：

import mysql.connector
from mysql.connector import Error
from PIL import Image

# 读取要写入的图片
img = Image.open('image.png')
# 将图片转换为二进制格式
with open("image.bin", "wb") as f:
    f.write(img.tobytes())

# 连接数据库
try:
    conn = mysql.connector.connect(host='localhost',
                                   database='my_database',
                                   user='my_username',
                                   password='my_password')
    if conn.is_connected():
        print('Connected to MySQL database')

    # 将二进制数据写入数据库
    cursor = conn.cursor()
    sql_insert_blob_query = """ INSERT INTO my_table
                          (id, image_data) VALUES (%s,%s)"""

    with open("image.bin", "rb") as f:
        image_blob = f.read()
        # 执行 SQL 语句并提交到数据库
        cursor.execute(sql_insert_blob_query, (1, image_blob))
        conn.commit()
        print("Image and file inserted successfully as a BLOB into MySQL table")

except Error as e:
    print(e)

finally:
    cursor.close()
    conn.close()

要从数据库中读取图像，可以使用以下代码：

# 连接数据库
try:
    conn = mysql.connector.connect(host='localhost',
                                   database='my_database',
                                   user='my_username',
                                   password='my_password')
    if conn.is_connected():
        print('Connected to MySQL database')

    # 从数据库中读取二进制数据
    cursor = conn.cursor()
    sql_fetch_blob_query = """SELECT image_data FROM my_table WHERE id = %s"""

    cursor.execute(sql_fetch_blob_query, (1,))
    record = cursor.fetchone()

    # 将数据转换为图像文件并保存到磁盘上
    with open("image_out.png", "wb") as f:
        f.write(record[0])

except Error as e:
    print(e)

finally:
    cursor.close()
    conn.close()

这将从数据库中读取id为1的记录中的图像数据，并将其保存为名为“image_out.png”的文件。