在Flask-SQLAlchemy中生成唯一6位ID的策略与实践

import uuid

def generate_truncated_uuid_id():
    # 生成一个UUID并截取前6位
    return str(uuid.uuid4())[:6]

# 在模型中使用
class Item(db.Model):
    id = db.Column(db.String(6), primary_key=True, default=generate_truncated_uuid_id, unique=True)
    # 其他属性

class Item(db.Model):
    id = db.Column(db.String(6), primary_key=True, unique=True)
    # 其他属性

import secrets
import string

def generate_secure_alphanumeric_id(length=6):
    """
    生成一个指定长度的加密安全的随机字母数字字符串。
    """
    # 包含所有大小写字母和数字
    characters = string.ascii_letters + string.digits
    # 从可用字符中随机选择，组合成指定长度的字符串
    return ''.join(secrets.choice(characters) for _ in range(length))

# 示例：生成一个6位ID
# secure_id = generate_secure_alphanumeric_id(6)
# print(secure_id) # 例如：'aB3xZ9'

from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import Column, String, Integer, DateTime
import secrets
import string

db = SQLAlchemy() # 假设db实例已初始化

def generate_secure_alphanumeric_id(length=6):
    characters = string.ascii_letters + string.digits
    return ''.join(secrets.choice(characters) for _ in range(length))

class Item(db.Model):
    __tablename__ = 'items' # 建议明确指定表名
    id = Column(String(6), primary_key=True, default=lambda: generate_secure_alphanumeric_id(6), unique=True)
    name = Column(String(100), nullable=False)
    description = Column(String(255))
    created_at = Column(DateTime, default=db.func.now())

    def __repr__(self):
        return f"<Item {self.id} - {self.name}>"

# 示例：创建新Item
# new_item = Item(name="Sample Item", description="This is a test item.")
# db.session.add(new_item)
# db.session.commit()
# print(new_item.id) # 会自动生成一个6位的ID

from sqlalchemy.exc import IntegrityError

def create_item_with_unique_id(name, description):
    max_retries = 5 # 设置最大重试次数
    for _ in range(max_retries):
        try:
            new_item = Item(name=name, description=description)
            db.session.add(new_item)
            db.session.commit()
            return new_item
        except IntegrityError:
            db.session.rollback() # 回滚事务，释放锁
            print("ID collision detected, retrying...")
            # 循环会自动再次尝试生成ID
    raise Exception("Failed to create item after multiple retries due to ID collisions.")

# 使用示例
# try:
#     item = create_item_with_unique_id("Another Item", "This item will be unique.")
#     print(f"Item created with ID: {item.id}")
# except Exception as e:
#     print(e)