{"id":1165643,"date":"2025-01-15T15:23:03","date_gmt":"2025-01-15T07:23:03","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/1165643.html"},"modified":"2025-01-15T15:23:07","modified_gmt":"2025-01-15T07:23:07","slug":"python2%e5%a6%82%e4%bd%95%e5%bc%95%e5%85%a5sql","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/1165643.html","title":{"rendered":"python2\u5982\u4f55\u5f15\u5165sql"},"content":{"rendered":"

\"python2\u5982\u4f55\u5f15\u5165sql\"<\/p>\n

\u5728Python 2\u4e2d\u5f15\u5165SQL\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528\u4e0d\u540c\u7684\u6570\u636e\u5e93\u5e93\u6765\u5b9e\u73b0\uff0c\u6700\u5e38\u89c1\u7684\u5e93\u5305\u62ecsqlite3\u3001MySQLdb\u3001SQLAlchemy<\/strong>\u7b49\u3002sqlite3\u662fPython\u6807\u51c6\u5e93\u7684\u4e00\u90e8\u5206\uff0c\u4e0d\u9700\u8981\u989d\u5916\u5b89\u88c5\uff0cMySQLdb\u9700\u8981\u5b89\u88c5MySQL-Python\u5305\uff0cSQLAlchemy\u662f\u4e00\u4e2aORM\uff08\u5bf9\u8c61\u5173\u7cfb\u6620\u5c04\uff09\u5de5\u5177\uff0c\u53ef\u4ee5\u63d0\u4f9b\u66f4\u9ad8\u7ea7\u522b\u7684\u6570\u636e\u5e93\u64cd\u4f5c\u63a5\u53e3<\/strong>\u3002\u5176\u4e2d\uff0cSQLAlchemy\u4e0d\u4ec5\u652f\u6301\u591a\u79cd\u6570\u636e\u5e93\uff0c\u8fd8\u63d0\u4f9b\u4e86\u7075\u6d3b\u7684\u67e5\u8be2\u751f\u6210\u548c\u5bf9\u8c61\u7ba1\u7406\u529f\u80fd\u3002\u4e0b\u9762\u5c06\u8be6\u7ec6\u4ecb\u7ecdSQLAlchemy\u7684\u4f7f\u7528\u3002<\/p>\n<\/p>\n

\u4e00\u3001SQLAlchemy\u7684\u5b89\u88c5\u4e0e\u57fa\u672c\u4f7f\u7528<\/h3>\n<\/p>\n

1. \u5b89\u88c5SQLAlchemy<\/h4>\n<\/p>\n

\u9996\u5148\uff0c\u4f60\u9700\u8981\u5b89\u88c5SQLAlchemy\u5e93\u3002\u4f60\u53ef\u4ee5\u4f7f\u7528pip\u6765\u5b89\u88c5\u5b83\uff1a<\/p>\n<\/p>\n

pip install SQLAlchemy<\/p>\n
<\/code><\/pre>\n<\/p>\n
2. \u521b\u5efa\u6570\u636e\u5e93\u8fde\u63a5<\/h4>\n<\/p>\n
\u521b\u5efa\u6570\u636e\u5e93\u8fde\u63a5\u662f\u4f7f\u7528SQLAlchemy\u7684\u7b2c\u4e00\u6b65\u3002\u4f60\u9700\u8981\u6307\u5b9a\u6570\u636e\u5e93\u7684\u7c7b\u578b\u548c\u8fde\u63a5\u5b57\u7b26\u4e32\u3002<\/p>\n<\/p>\n
from sqlalchemy import create_engine<\/p>\n
\u8fde\u63a5\u5230SQLite\u6570\u636e\u5e93<\/strong><\/h2>\n
engine = create_engine('sqlite:\/\/\/example.db')<\/p>\n
\u8fde\u63a5\u5230MySQL\u6570\u636e\u5e93<\/strong><\/h2>\n
engine = create_engine('mysql+mysqldb:\/\/user:password@host\/database')<\/strong><\/h2>\n
<\/code><\/pre>\n<\/p>\n
\u4e8c\u3001\u5b9a\u4e49\u8868\u7ed3\u6784\u548c\u6a21\u578b<\/h3>\n<\/p>\n
SQLAlchemy\u4f7f\u7528Python\u7c7b\u6765\u8868\u793a\u6570\u636e\u5e93\u8868\u3002\u4f60\u9700\u8981\u5b9a\u4e49\u4e00\u4e2a\u7ee7\u627f\u81eaBase<\/code>\u7c7b\u7684\u6a21\u578b\u7c7b\u6765\u6620\u5c04\u5230\u6570\u636e\u5e93\u8868\u3002<\/p>\n<\/p>\n
from sqlalchemy.ext.declarative import declarative_base<\/p>\n
from sqlalchemy import Column, Integer, String<\/p>\n
Base = declarative_base()<\/p>\n
class User(Base):<\/p>\n
    __tablename__ = 'users'<\/p>\n
    id = Column(Integer, primary_key=True)<\/p>\n
    name = Column(String)<\/p>\n
    age = Column(Integer)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e09\u3001\u521b\u5efa\u8868<\/h3>\n<\/p>\n
\u4e00\u65e6\u4f60\u5b9a\u4e49\u4e86\u6a21\u578b\u7c7b\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528SQLAlchemy\u6765\u521b\u5efa\u76f8\u5e94\u7684\u6570\u636e\u5e93\u8868\u3002<\/p>\n<\/p>\n
Base.metadata.create_all(engine)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001\u6570\u636e\u5e93\u64cd\u4f5c\uff08\u589e\u3001\u5220\u3001\u6539\u3001\u67e5\uff09<\/h3>\n<\/p>\n
1. \u521b\u5efa\u4f1a\u8bdd<\/h4>\n<\/p>\n
SQLAlchemy\u4f7f\u7528\u4f1a\u8bdd\u6765\u7ba1\u7406\u6570\u636e\u5e93\u64cd\u4f5c\u3002\u4f60\u9700\u8981\u521b\u5efa\u4e00\u4e2a\u4f1a\u8bdd\u5bf9\u8c61\u3002<\/p>\n<\/p>\n
from sqlalchemy.orm import sessionmaker<\/p>\n
Session = sessionmaker(bind=engine)<\/p>\n
session = Session()<\/p>\n
<\/code><\/pre>\n<\/p>\n
2. \u63d2\u5165\u6570\u636e<\/h4>\n<\/p>\n
\u4f60\u53ef\u4ee5\u521b\u5efa\u6a21\u578b\u5b9e\u4f8b\u5e76\u5c06\u5176\u6dfb\u52a0\u5230\u4f1a\u8bdd\u4e2d\uff0c\u7136\u540e\u63d0\u4ea4\u4f1a\u8bdd\u6765\u63d2\u5165\u6570\u636e\u3002<\/p>\n<\/p>\n
new_user = User(name='John Doe', age=30)<\/p>\n
session.add(new_user)<\/p>\n
session.commit()<\/p>\n
<\/code><\/pre>\n<\/p>\n
3. \u67e5\u8be2\u6570\u636e<\/h4>\n<\/p>\n
\u4f60\u53ef\u4ee5\u4f7f\u7528\u4f1a\u8bdd\u5bf9\u8c61\u6765\u67e5\u8be2\u6570\u636e\u3002<\/p>\n<\/p>\n
users = session.query(User).all()<\/p>\n
for user in users:<\/p>\n
    print(user.name, user.age)<\/p>\n
<\/code><\/pre>\n<\/p>\n
4. \u66f4\u65b0\u6570\u636e<\/h4>\n<\/p>\n
\u4f60\u53ef\u4ee5\u67e5\u8be2\u5230\u6570\u636e\u5e76\u4fee\u6539\u5176\u5c5e\u6027\uff0c\u7136\u540e\u63d0\u4ea4\u4f1a\u8bdd\u6765\u66f4\u65b0\u6570\u636e\u3002<\/p>\n<\/p>\n
user = session.query(User).filter_by(name='John Doe').first()<\/p>\n
user.age = 31<\/p>\n
session.commit()<\/p>\n
<\/code><\/pre>\n<\/p>\n
5. \u5220\u9664\u6570\u636e<\/h4>\n<\/p>\n
\u4f60\u53ef\u4ee5\u67e5\u8be2\u5230\u6570\u636e\u5e76\u5c06\u5176\u5220\u9664\uff0c\u7136\u540e\u63d0\u4ea4\u4f1a\u8bdd\u6765\u5220\u9664\u6570\u636e\u3002<\/p>\n<\/p>\n
user = session.query(User).filter_by(name='John Doe').first()<\/p>\n
session.delete(user)<\/p>\n
session.commit()<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e94\u3001\u4f7f\u7528\u5173\u7cfb\uff08\u591a\u5bf9\u4e00\u3001\u4e00\u5bf9\u591a\u3001\u591a\u5bf9\u591a\uff09<\/h3>\n<\/p>\n
SQLAlchemy\u652f\u6301\u5b9a\u4e49\u5173\u7cfb\uff0c\u4f7f\u5f97\u4f60\u53ef\u4ee5\u5728\u6a21\u578b\u7c7b\u4e4b\u95f4\u521b\u5efa\u5173\u8054\u3002<\/p>\n<\/p>\n
1. \u591a\u5bf9\u4e00\u5173\u7cfb<\/h4>\n<\/p>\n
from sqlalchemy import ForeignKey<\/p>\n
from sqlalchemy.orm import relationship<\/p>\n
class Address(Base):<\/p>\n
    __tablename__ = 'addresses'<\/p>\n
    id = Column(Integer, primary_key=True)<\/p>\n
    user_id = Column(Integer, ForeignKey('users.id'))<\/p>\n
    emAI<\/a>l = Column(String)<\/p>\n
    user = relationship('User', back_populates='addresses')<\/p>\n
User.addresses = relationship('Address', order_by=Address.id, back_populates='user')<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516d\u3001\u4e8b\u52a1\u7ba1\u7406<\/h3>\n<\/p>\n
SQLAlchemy\u652f\u6301\u4e8b\u52a1\u7ba1\u7406\uff0c\u786e\u4fdd\u6570\u636e\u64cd\u4f5c\u7684\u539f\u5b50\u6027\u548c\u4e00\u81f4\u6027\u3002<\/p>\n<\/p>\n
from sqlalchemy.orm import sessionmaker<\/p>\n
Session = sessionmaker(bind=engine)<\/p>\n
session = Session()<\/p>\n
try:<\/p>\n
    new_user = User(name='Jane Doe', age=25)<\/p>\n
    session.add(new_user)<\/p>\n
    session.commit()<\/p>\n
except:<\/p>\n
    session.rollback()<\/p>\n
    raise<\/p>\n
finally:<\/p>\n
    session.close()<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e03\u3001\u8fde\u63a5\u6c60\u4e0e\u6027\u80fd\u4f18\u5316<\/h3>\n<\/p>\n
SQLAlchemy\u652f\u6301\u8fde\u63a5\u6c60\uff0c\u53ef\u4ee5\u63d0\u9ad8\u6570\u636e\u5e93\u8fde\u63a5\u7684\u91cd\u7528\u6027\u548c\u6027\u80fd\u3002<\/p>\n<\/p>\n
from sqlalchemy.pool import QueuePool<\/p>\n
engine = create_engine('mysql+mysqldb:\/\/user:password@host\/database', poolclass=QueuePool, pool_size=5, max_overflow=10)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516b\u3001SQLAlchemy\u7684\u9ad8\u7ea7\u7279\u6027<\/h3>\n<\/p>\n
1. \u81ea\u5b9a\u4e49\u67e5\u8be2<\/h4>\n<\/p>\n
\u4f60\u53ef\u4ee5\u4f7f\u7528SQLAlchemy\u7684\u67e5\u8be2\u751f\u6210\u5668\u6765\u521b\u5efa\u81ea\u5b9a\u4e49\u67e5\u8be2\u3002<\/p>\n<\/p>\n
from sqlalchemy import or_<\/p>\n
users = session.query(User).filter(or_(User.name == 'John Doe', User.age < 30)).all()<\/p>\n
<\/code><\/pre>\n<\/p>\n
2. \u4f7f\u7528\u539f\u751fSQL<\/h4>\n<\/p>\n
\u4f60\u53ef\u4ee5\u4f7f\u7528SQLAlchemy\u6267\u884c\u539f\u751fSQL\u67e5\u8be2\u3002<\/p>\n<\/p>\n
result = engine.execute('SELECT * FROM users')<\/p>\n
for row in result:<\/p>\n
    print(row)<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e5d\u3001\u603b\u7ed3<\/h3>\n<\/p>\n
\u901a\u8fc7\u4f7f\u7528SQLAlchemy\uff0c\u4f60\u53ef\u4ee5\u5728Python 2\u4e2d\u8f7b\u677e\u5730\u5f15\u5165\u548c\u64cd\u4f5cSQL\u6570\u636e\u5e93\u3002SQLAlchemy\u4e0d\u4ec5\u63d0\u4f9b\u4e86\u5bf9\u6570\u636e\u5e93\u7684\u57fa\u7840\u64cd\u4f5c\u652f\u6301\uff0c\u8fd8\u63d0\u4f9b\u4e86\u4e30\u5bcc\u7684\u9ad8\u7ea7\u7279\u6027\uff0c\u4f7f\u5f97\u6570\u636e\u5e93\u64cd\u4f5c\u66f4\u52a0\u7075\u6d3b\u548c\u9ad8\u6548\u3002\u65e0\u8bba\u4f60\u662f\u9700\u8981\u7b80\u5355\u7684CRUD\u64cd\u4f5c\uff0c\u8fd8\u662f\u590d\u6742\u7684\u4e8b\u52a1\u7ba1\u7406\u548c\u81ea\u5b9a\u4e49\u67e5\u8be2\uff0cSQLAlchemy\u90fd\u80fd\u6ee1\u8db3\u4f60\u7684\u9700\u6c42<\/strong>\u3002\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u6839\u636e\u5177\u4f53\u7684\u9700\u6c42\u9009\u62e9\u5408\u9002\u7684\u5e93\u548c\u5de5\u5177\uff0c\u53ef\u4ee5\u5927\u5927\u63d0\u9ad8\u5f00\u53d1\u6548\u7387\u548c\u4ee3\u7801\u8d28\u91cf\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
 \u5982\u4f55\u5728Python 2\u4e2d\u8fde\u63a5\u5230SQL\u6570\u636e\u5e93\uff1f<\/strong>
\u5728Python 2\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528\u591a\u79cd\u5e93\u6765\u8fde\u63a5SQL\u6570\u636e\u5e93\uff0c\u4f8b\u5982sqlite3<\/code>\u3001MySQLdb<\/code>\u6216psycopg2<\/code>\u3002\u8fde\u63a5\u6570\u636e\u5e93\u7684\u57fa\u672c\u6b65\u9aa4\u5305\u62ec\u5bfc\u5165\u76f8\u5e94\u7684\u5e93\u3001\u521b\u5efa\u8fde\u63a5\u5bf9\u8c61\u3001\u83b7\u53d6\u6e38\u6807\u5e76\u6267\u884cSQL\u8bed\u53e5\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u4f7f\u7528sqlite3<\/code>\u5e93\u8fde\u63a5SQLite\u6570\u636e\u5e93\u7684\u793a\u4f8b\u4ee3\u7801\uff1a  <\/p>\n
import sqlite3\n\n# \u521b\u5efa\u6570\u636e\u5e93\u8fde\u63a5\nconn = sqlite3.connect('example.db')\n\n# \u521b\u5efa\u6e38\u6807\ncursor = conn.cursor()\n\n# \u6267\u884cSQL\u8bed\u53e5\ncursor.execute('SELECT * FROM table_name')\n\n# \u5904\u7406\u67e5\u8be2\u7ed3\u679c\nresults = cursor.fetchall()\nfor row in results:\n    print(row)\n\n# \u5173\u95ed\u8fde\u63a5\nconn.close()\n<\/code><\/pre>\n
Python 2\u4e2d\u5982\u4f55\u6267\u884cSQL\u67e5\u8be2\u5e76\u5904\u7406\u7ed3\u679c\uff1f<\/strong>
\u5728Python 2\u4e2d\u6267\u884cSQL\u67e5\u8be2\u65f6\uff0c\u901a\u5e38\u4f1a\u4f7f\u7528\u6e38\u6807\u5bf9\u8c61\u3002\u6e38\u6807\u5141\u8bb8\u60a8\u6267\u884cSQL\u547d\u4ee4\u5e76\u83b7\u53d6\u7ed3\u679c\u3002\u6267\u884c\u67e5\u8be2\u540e\uff0c\u53ef\u4ee5\u4f7f\u7528fetchall()<\/code>\u3001fetchone()<\/code>\u6216fetchmany(size)<\/code>\u65b9\u6cd5\u6765\u63d0\u53d6\u7ed3\u679c\u3002\u4f8b\u5982\uff0c\u4f7f\u7528fetchall()<\/code>\u53ef\u4ee5\u83b7\u53d6\u6240\u6709\u67e5\u8be2\u7ed3\u679c\uff0cfetchone()<\/code>\u4ec5\u8fd4\u56de\u4e00\u6761\u8bb0\u5f55\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u793a\u4f8b\uff1a  <\/p>\n
cursor.execute('SELECT column_name FROM table_name WHERE condition')\nresults = cursor.fetchall()  # \u83b7\u53d6\u6240\u6709\u7ed3\u679c\nfor row in results:\n    print(row)\n<\/code><\/pre>\n
\u5728Python 2\u4e2d\u5982\u4f55\u5904\u7406SQL\u5f02\u5e38\uff1f<\/strong>
\u5904\u7406SQL\u5f02\u5e38\u662f\u4fdd\u8bc1\u7a0b\u5e8f\u7a33\u5b9a\u6027\u7684\u91cd\u8981\u73af\u8282\u3002\u53ef\u4ee5\u4f7f\u7528try...except<\/code>\u7ed3\u6784\u6765\u6355\u83b7\u53ef\u80fd\u51fa\u73b0\u7684\u6570\u636e\u5e93\u9519\u8bef\u3002\u4f8b\u5982\uff0c\u8fde\u63a5\u5931\u8d25\u3001\u67e5\u8be2\u8bed\u6cd5\u9519\u8bef\u7b49\u90fd\u53ef\u4ee5\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u5904\u7406\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a  <\/p>\n
try:\n    conn = sqlite3.connect('example.db')\n    cursor = conn.cursor()\n    cursor.execute('SELECT * FROM non_existent_table')\nexcept sqlite3.Error as e:\n    print("An error occurred:", e)\nfinally:\n    if conn:\n        conn.close()  # \u786e\u4fdd\u8fde\u63a5\u5173\u95ed\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"\u5728Python 2\u4e2d\u5f15\u5165SQL\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528\u4e0d\u540c\u7684\u6570\u636e\u5e93\u5e93\u6765\u5b9e\u73b0\uff0c\u6700\u5e38\u89c1\u7684\u5e93\u5305\u62ecsqlite3\u3001MySQLdb\u3001 […]","protected":false},"author":3,"featured_media":1165656,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1165643"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=1165643"}],"version-history":[{"count":"1","href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1165643\/revisions"}],"predecessor-version":[{"id":1165658,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1165643\/revisions\/1165658"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/1165656"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=1165643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=1165643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=1165643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}