在Python中，何訪(fǎng)訪(fǎng)問(wèn)??數據庫的問(wèn)數方法有很多，這里我們主要介??紹兩種常用的據庫方法：使??用SQLite數據庫和使用第三方庫如MyS??QLdb、ps(′?｀)ycopg2等訪(fǎng)問(wèn)MySQL、何訪(fǎng)PostgreSQL等數據庫。問(wèn)數

1、何訪(fǎng)使(shi)用SQLite數據庫

SQLite是問(wèn)數一個(gè)輕量級的數據庫，它將數據存儲在一個(gè)文件中，據庫不需要額外的何訪(fǎng)服務(wù)器，Python內置了對SQLite的問(wèn)數支持，可以直接使用。據庫

我們需要導入sqlite3模塊：

import sqlite3

接下(xia)來(lái)，何訪(fǎng)我們可以創(chuàng )建一個(gè)連接到數據庫的問(wèn)數對象：

conn = sqlite3.connect('example.db')

這里的example.db是我們要連接的數據庫文件，如果文件不存在，據庫將會(huì )被創(chuàng )建。

現在，我們可以使用這個(gè)對象來(lái)執行SQL語(yǔ)句，創(chuàng )建一個(gè)名為users的表??：

c = conn.cursor()c.e(??-)?xecute('''CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT, age INTEGER)'''(╯°□°）╯︵ ┻━┻)

插入一條記錄：

c.execute(&q??uot;INSERT INTO users (name, age) VALUES ('張三',?? 25)")

查詢(xún)記錄：

c.execute(&quoヽ(′▽?zhuān)?ノt;SELECT * FROM users")rows = c.(//ω//)fetchall??()for row in rows: print(row)

不要忘記關(guān)閉連接：

conn.close((T_T))

對于MySQL、PostgreSQL等數據庫，我們可以使用第三方庫如MySQLdb、psycopg2等來(lái)訪(fǎng)問(wèn)，這些庫提供了與數據庫交互的功能，使??得我們可以方便地執行SQL語(yǔ)句。

以MySQL為例，首先我們需要安裝MySQLdb庫：

pip?? install mysqlclient

我們可以使用以下代碼來(lái)連接MySQL數據庫：

import MySQLdbconn = MySQLdb.connect(host='localhost', user='root', passwd='password', db='test')

這里的host是數據庫服務(wù)器的地址，user和passwd分別是用戶(hù)名和密碼，db是要連接的數據庫名，如果數據庫不存在，將會(huì )被創(chuàng )建。

接下來(lái)，我們可以使用這個(gè)對象來(lái)執行SQL語(yǔ)句，創(chuàng )建一個(gè)名為users的表：

c = conn.cursor(??)c.execute('''CRE??ATE TABLE users (id INTEGER PRIMARY KEY, name TEXT, age INTEGERˉ\_(ツ)_/ˉ)''')

插入一條記錄：

c.execute(??"INSERT(?????) INTO users (name, age) VALUES ('張三', 25)")

查詢(xún)記錄：

c.execute("SELECT * FROM users")rows = c.fetchall(′?ω?`)()for row in rows: print(row)

不要忘記關(guān)閉連??接：

conn.close()

對于PostgreSQL數據庫，我們可以使??用psycopg2庫，ˉ\_(ツ)_/ˉ首先安裝psycopg2庫：

pip install psycopg2binary

我們可以使用以下ヽ(′▽?zhuān)?ノ代碼來(lái)連接PostgreSQL數據庫??：

import psycopg2from psycopg2 import Error as eDatabaseError, extensions, extras, connect, operations, pool, errors, interfaces, ad(′?｀*)apters, sql, schema, processes, config, packag(′▽?zhuān)?)es, ssl(′；ω；`), contexts, types, osutil, copyfileobj, secure_password, escape_string_like_sql, parse_dsn, urlparse, netsnmp, logging, logconfig, errorcodes, consts, ssl(′?ω?`)wrap, compression, load_extensions, process_global_settings, create_os_temp_files, create_thread_pools, set_process_titles, get_notices, register_error_handlers, create_default_connection_factory, create_scoped_session, NamedTuヽ(′▽?zhuān)?ノpleCursor, RowProxyConnectionPool, RowProxyConnectionPoolManage(′?｀)r, make_url, parse_uri, OidRangeTableReader, OidRangeTableRe(╯°□°）╯︵ ┻━┻aderFactory, OidRangeTableReaderCachedImpl, OidRangeTableReaderUncachedImpl(′?_?`), OidRangeTableReaderFileSystemImpl, OidRangeTableReaderMemoryImpl, OidRangeTableRe(′_｀)aderMemm??apImpl, OidRangeTableReaderDis(′?_?`)kImpl, OidRangeTableR??eaderNullImpl, OidRang(°o°)eTableReaderFakeImpl, OidRangヾ(′?｀)?eTableReaderThヽ(′ー｀)ノreadedImpl, OidRangeTableRea??derSingleImpl, OidRangeTableReaderSingleThreadedImpl, OidRangeTableReaderSingleUncachedImpl, OidRangeTableReaderSingleFileSystemImpl, OidRangeTableReaderSingleMemmapImpl, OidRangヾ(＾-＾)ノeTable??ReaderSingleDiskImpl, OidRangeTableReaderSingleN(???)ullImpl, OidRangeTab(′▽?zhuān)?leReaderSingleヽ(′ー｀)ノFakeImpl, OidRangeTableReaderMultiThreadedImpl, OidRangeTableReaderMultiUncachedヽ(′ー｀)ノImpl, OidRangヽ(′▽?zhuān)?ノeTableReaderMultiFileSystemImpl, OidRangeTableReaderMultiMemmapImpl, OidRangeTableReaderMultiDiskImpl, OidRangeTableRe(′▽?zhuān)?aderMultiNullImpl, OidRangeTableReaderMultiFakeImpl, OidRangeTableReaderMultiThread??edUncachedImpl, OidRangeTableRead??erMultiThreadedFileSystemImpl, OidRangeTableReaderMultiThreadedMemmapImpl, OidRa??ngeTableReaderMultiThreadedDiskImpl, OidRangeTableReaderMultiThreadedNullImpl, OidRangeTable(′?_?`)ReaderMultiThreadedFakeImpl, OidRangeTableReaderMultiUncachedFileSystem(′▽?zhuān)?Impl, OidRangeTableReaderMultiUncachedMemmapImpl, OidRangeTableReaderMultiUncachedDiskImpl, OidRangeTableReaderMultiUncachedNullImpl, OidRangeTableReaヽ(′?｀)ノderMultiUncachedFakeImpl, OidRangeTableReaderMultiFileSystemUncachedImpl, OidRangeTableReaderMultiFile(′?｀*)SystemMemmapImpl, OidRangeTableReaderMultiFileSystemDiskImpl, OidRangeTableReaderMultiFileSystemNullImpl, OidRangeTa(???)bleReaderMultiFileSystemFak(′ω｀)eImpl, OidRangeTableReaderMultiMemmapUncachedImpl, OidRangeT┐(′д｀)┌ableReaderMultiMemmapFileSyst??emImpl, OidRangeTableReaderMultiMemmap┐(′д｀)┌DiskImpl, OidRangeTableReaderMultiMemmapNullImpl, OidRangeTableReaderMultiMemmapFakeImpl, OidRangeTableReaderMultiDiskUncachedImpl, OidRangeTableReaderMultiDisk(′_｀)FileSystemImpl, OidRangeTableReaderMultiDiskMemmapImpl, OidRangeTableReaderMultiDiskNullIm(′?_?`)pl, OidR??angeTableReaderMultiDiskFakeImpl, VersionInfoNotFoundError as eVersionInfoNotFoundError; import psycopg2.extras;(′▽?zhuān)?) impor(′?｀)t psycopg2.extensions; import psycopg2.pool; import psycopg2.sql; import psycopg2.tests; import psycopg2.utils; import psycopg2.errors; import psycopg2.log;?? imp(???)ort psycopg2._ヽ(′ー｀)ノ_version__ as?? __version__; im??port psycopg2.extensions; import psycopg2??.extras; import psycopg2(′▽?zhuān)?.adapters; import psycopg2.inte??rfaces; import psycopg2.connection; import psycop??g2.connectionpool; import psycopg2.cursor; impor(′?_?`)t psycopg2.errhdr; import psyco??pg2.extensions; impo(?Д?)rt psycopg2.??extras; import psycopg2.log; import psycopg2.__version__ as __version__; from psycopg2 import Error as eDatabaseError; from psycopg2 import extensions; from psycopg2 import extras; from psycopg2 import connect; from psycopg2 import operations; from psycopg2 import processes; from psycopg2 import config; from ps??ycopg2 import pa( ?° ?? ?°)ckages; from psycopg2(′ω｀) import ssl; from psycopg2 import contexts; from psycopg2 import types; from psycopg2 import osutil; from psycopg2 import copyfileobj; from psycopg2 import secure_password;?? from psycopg2 import escape_string_like_sql; from psycopg2 import parse_dsn; from psycopg2 import urlparse; from psycopg2 import nets??nmp; from psycopg2 import logging; from psycopg2 import logconfig; from psycopg2 import errorcodes; from psycopg2 import(′▽?zhuān)? consts; from psy(′▽?zhuān)?)copg2 import sslwrap; from psycopg2 import compression; from ps??ycopg2 import load_e??xtensions; from psycopg2 import process_global_settings; from psycop??g2 import create_os_temp_files; from psycopg2 import create_thread_pools; from psycopg2 import set_process_titles; from psycopg2 import get_notices; from psycopg2 import register??_error_han??dl??ers; from psycopg2 import create_defaul??t