from sqlalchemy import create_engine
engine = create_engine("mysql://root:@localhost:3306/webpy?charset=utf8",encoding="utf-8", echo=True)

# -*- coding: utf-8 -*-
__author__ = 'ghost'

from sqlalchemy import create_engine, Table, Column, Integer, String, MetaData, ForeignKey
# 连接数据库 
engine = create_engine("mysql://root:@localhost:3306/webpy?charset=utf8",encoding="utf-8", echo=True)
# 获取元数据
metadata = MetaData()
# 定义表
user = Table('user', metadata,
    Column('id', Integer, primary_key=True),
    Column('name', String(20)),
    Column('fullname', String(40)),
  )

address = Table('address', metadata,
    Column('id', Integer, primary_key=True),
    Column('user_id', None, ForeignKey('user.id')),
    Column('email', String(60), nullable=False)
  )
# 创建数据表，如果数据表存在，则忽视
metadata.create_all(engine)
# 获取数据库连接
conn = engine.connect()

>>> i = user.insert()  # 使用查询
>>> i 
<sqlalchemy.sql.dml.Insert object at 0x0000000002637748>
>>> print i # 内部构件的sql语句
INSERT INTO "user" (id, name, fullname) VALUES (:id, :name, :fullname)
>>> u = dict(name='jack', fullname='jack Jone')
>>> r = conn.execute(i, **u) # 执行查询，第一个为查询对象，第二个参数为一个插入数据字典，如果插入的是多个对象，就把对象字典放在列表里面
>>> r
<sqlalchemy.engine.result.ResultProxy object at 0x0000000002EF9390>
>>> r.inserted_primary_key # 返回插入行 主键 id
[4L]
>>> addresses
[{'user_id': 1, 'email': 'jack@yahoo.com'}, {'user_id': 1, 'email': 'jack@msn.com'}, {'user_id': 2, 'email': 'www@www.org'}, {'user_id': 2, 'email': 'wendy@aol.com'}]
>>> i = address.insert()
>>> r = conn.execute(i, addresses)  # 插入多条记录
>>> r
<sqlalchemy.engine.result.ResultProxy object at 0x0000000002EB5080>
>>> r.rowcount  #返回影响的行数
4L

>>> i = user.insert().values(name='tom', fullname='tom Jim')
>>> i.compile()
<sqlalchemy.sql.compiler.SQLCompiler object at 0x0000000002F6F390>
>>> print i.compile()
INSERT INTO "user" (name, fullname) VALUES (:name, :fullname)
>>> print i.compile().params
{'fullname': 'tom Jim', 'name': 'tom'}
>>> r = conn.execute(i)
>>> r.rowcount
1L

>>> s = select([user]) # 查询 user表
>>> s
<sqlalchemy.sql.selectable.Select at 0x25a7748; Select object>
>>> print s
SELECT "user".id, "user".name, "user".fullname 
FROM "user"

>>> user.c # 表 user 的字段column对象
<sqlalchemy.sql.base.ImmutableColumnCollection object at 0x0000000002E804A8>
>>> print user.c
['user.id', 'user.name', 'user.fullname']
>>> s = select([user.c.name,user.c.fullname])
>>> r = conn.execute(s)
>>> r
<sqlalchemy.engine.result.ResultProxy object at 0x00000000025A7748>
>>> r.rowcount # 影响的行数
5L
>>> ru = r.fetchall() 
>>> ru
[(u'hello', u'hello world'), (u'Jack', u'Jack Jone'), (u'Jack', u'Jack Jone'), (u'jack', u'jack Jone'), (u'tom', u'tom Jim')]
>>> r 
<sqlalchemy.engine.result.ResultProxy object at 0x00000000025A7748>
>>> r.closed # 只要 r.fetchall() 之后，就会自动关闭 ResultProxy 对象
True

>>> s = select([user.c.name, address.c.user_id]).where(user.c.id==address.c.user_id)  # 使用了字段和字段比较的条件
>>> s
<sqlalchemy.sql.selectable.Select at 0x2f03390; Select object>
>>> print s
SELECT "user".name, address.user_id 
FROM "user", address 
WHERE "user".id = address.user_id

>>> print user.c.id == address.c.user_id # 返回一个编译的字符串
"user".id = address.user_id
>>> print user.c.id == 7
"user".id = :id_1  # 编译成为带参数的sql 语句片段字符串
>>> print user.c.id != 7
"user".id != :id_1
>>> print user.c.id > 7
"user".id > :id_1
>>> print user.c.id == None
"user".id IS NULL
>>> print user.c.id + address.c.id  # 使用两个整形的变成 +
"user".id + address.id
>>> print user.c.name + address.c.email # 使用两个字符串 变成 ||
"user".name || address.email

>>> print and_(
    user.c.name.like('j%'),
    user.c.id == address.c.user_id,
    or_(
      address.c.email == 'wendy@aol.com',
      address.c.email == 'jack@yahoo.com'
    ),
    not_(user.c.id>5))
"user".name LIKE :name_1 AND "user".id = address.user_id AND (address.email = :email_1 OR address.email = :email_2) AND "user".id <= :id_1
>>> 

>>> se_sql = [(user.c.fullname +", " + address.c.email).label('title')]
>>> wh_sql = and_(
       user.c.id == address.c.user_id,
       user.c.name.between('m', 'z'),
       or_(
         address.c.email.like('%@aol.com'),
         address.c.email.like('%@msn.com')
       )
     )
>>> print wh_sql
"user".id = address.user_id AND "user".name BETWEEN :name_1 AND :name_2 AND (address.email LIKE :email_1 OR address.email LIKE :email_2)
>>> s = select(se_sql).where(wh_sql)
>>> print s
SELECT "user".fullname || :fullname_1 || address.email AS title 
FROM "user", address 
WHERE "user".id = address.user_id AND "user".name BETWEEN :name_1 AND :name_2 AND (address.email LIKE :email_1 OR address.email LIKE :email_2)
>>> r = conn.execute(s)
>>> r.fetchall()

>>> text_sql = "SELECT id, name, fullname FROM user WHERE id=:id" # 原始sql语句，参数用（ ：value）表示
>>> s = text(text_sql)
>>> print s
SELECT id, name, fullname FROM user WHERE id=:id
>>> s
<sqlalchemy.sql.elements.TextClause object at 0x0000000002587668>
>>> conn.execute(s, id=3).fetchall()  # id=3 传递：id参数
[(3L, u'Jack', u'Jack Jone')]

>>> print user.join(address)
"user" JOIN address ON "user".id = address.user_id  # 因为开启了外键 ，所以join 能只能识别 on 条件
>>> print user.join(address, address.c.user_id==user.c.id) # 手动指定 on 条件
"user" JOIN address ON address.user_id = "user".id

>>> s = select([user.c.name, address.c.email]).select_from(user.join(address, user.c.id==address.c.user_id)) # 被jion的sql语句需要用 select_from方法配合


>>> s
<sqlalchemy.sql.selectable.Select at 0x2eb63c8; Select object>
>>> print s
SELECT "user".name, address.email 
FROM "user" JOIN address ON "user".id = address.user_id
>>> conn.execute(s).fetchall()
[(u'hello', u'jack@yahoo.com'), (u'hello', u'jack@msn.com'), (u'hello', u'jack@yahoo.com'), (u'hello', u'jack@msn.com'), (u'Jack', u'www@www.org'), (u'Jack', u'wendy@aol.com'), (u'Jack', u'www@www.org'), (u'Jack', u'wendy@aol.com')]

>>> s = select([user.c.name]).order_by(user.c.name) # order_by
>>> print s
SELECT "user".name 
FROM "user" ORDER BY "user".name
>>> s = select([user]).order_by(user.c.name.desc())
>>> print s
SELECT "user".id, "user".name, "user".fullname 
FROM "user" ORDER BY "user".name DESC
>>> s = select([user]).group_by(user.c.name)    # group_by
>>> print s
SELECT "user".id, "user".name, "user".fullname 
FROM "user" GROUP BY "user".name
>>> s = select([user]).order_by(user.c.name.desc()).limit(1).offset(3) # limit(1).offset(3)
>>> print s
SELECT "user".id, "user".name, "user".fullname 
FROM "user" ORDER BY "user".name DESC
 LIMIT :param_1 OFFSET :param_2
[(4L, u'jack', u'jack Jone')]

>>> s = user.update()
>>> print s
UPDATE "user" SET id=:id, name=:name, fullname=:fullname
>>> s = user.update().values(fullname=user.c.name)      # values 指定了更新的字段
>>> print s
UPDATE "user" SET fullname="user".name
>>> s = user.update().where(user.c.name == 'jack').values(name='ed') # where 进行选择过滤
>>> print s 
UPDATE "user" SET name=:name WHERE "user".name = :name_1
>>> r = conn.execute(s)
>>> print r.rowcount     # 影响行数
3

>>> s = user.update().where(user.c.name==bindparam('oldname')).values(name=bindparam('newname'))  # oldname 与下面的传入的从拿书进行绑定，newname也一样
>>> print s
UPDATE "user" SET name=:newname WHERE "user".name = :oldname
>>> u = [{'oldname':'hello', 'newname':'edd'},
{'oldname':'ed', 'newname':'mary'},
{'oldname':'tom', 'newname':'jake'}]
>>> r = conn.execute(s, u)
>>> r.rowcount
5L

>>> r = conn.execute(address.delete()) # 清空表
>>> print r
<sqlalchemy.engine.result.ResultProxy object at 0x0000000002EAF550>
>>> r.rowcount
8L
>>> r = conn.execute(users.delete().where(users.c.name > 'm')) # 删除记录
>>> r.rowcount
3L

pip install flask-sqlalchemy

from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy


app = Flask(__name__)

#         dialect+driver://username:password@host:port/database?charset=utf8
# 配置 sqlalchemy 数据库驱动://数据库用户名:密码@主机地址:端口/数据库?编码
app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:@localhost:3306/sqlalchemy?charset=utf8'
# 初始化
db = SQLAlchemy(app)

class User(db.Model):
  """ 定义了三个字段， 数据库表名为model名小写
  """
  id = db.Column(db.Integer, primary_key=True)
  username = db.Column(db.String(80), unique=True)
  email = db.Column(db.String(120), unique=True)

  def __init__(self, username, email):
    self.username = username
    self.email = email

  def __repr__(self):
    return '<User %r>' % self.username

  def save(self):
    db.session.add(self)
    db.session.commit()

>>> from yourapp import db, User
>>> u = User(username='admin', email='admin@example.com') # 创建实例
>>> db.session.add(u)                   # 添加session
>>> db.session.commit()                  # 提交查询
>>> users = User.query.all()               # 查询

>>> u = User(username=u'人世间', email='rsj@example.com')
>>> u.save()

class Category(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  name = db.Column(db.String(50))

  def __init__(self, name):
    self.name = name

  def __repr__(self):
    return '<Category %r>' % self.name

class Post(db.Model):
  """ 定义了五个字段，分别是 id，title，body，pub_date，category_id
  """
  id = db.Column(db.Integer, primary_key=True)
  title = db.Column(db.String(80))
  body = db.Column(db.Text)
  pub_date = db.Column(db.String(20))
  # 用于外键的字段
  category_id = db.Column(db.Integer, db.ForeignKey('category.id'))
  # 外键对象，不会生成数据库实际字段
  # backref指反向引用，也就是外键Category通过backref(post_set)查询Post
  category = db.relationship('Category', backref=db.backref('post_set', lazy='dynamic'))


  def __init__(self, title, body, category, pub_date=None):
    self.title = title
    self.body = body
    if pub_date is None:
      pub_date = time.time()
    self.pub_date = pub_date
    self.category = category

  def __repr__(self):
    return '<Post %r>' % self.title

  def save(self):
    db.session.add(self)
    db.session.commit()

>>> c = Category(name='Python')
>>> c
<Category 'Python'>
>>> c.post_set
<sqlalchemy.orm.dynamic.AppenderBaseQuery object at 0x0000000003B58F60>
>>> c.post_set.all()
[]
>>> p = Post(title='hello python', body='python is cool', category=c)
>>> p.save()
>>> c.post_set
<sqlalchemy.orm.dynamic.AppenderBaseQuery object at 0x0000000003B73710>
>>> c.post_set.all()  # 反向查询
[<Post u'hello python'>]
>>> p
<Post u'hello python'>
>>> p.category
<Category u'Python'>
# 也可以使用category_id 字段来添加
>>> p = Post(title='hello flask', body='flask is cool', category_id=1)
>>> p.save()

post_tag = db.Table('post_tag',
          db.Column('post_id', db.Integer, db.ForeignKey('post.id')),
          db.Column('tag_id', db.Integer, db.ForeignKey('tag.id'))
        )

class Post(db.Model):

  id = db.Column(db.Integer, primary_key=True)
  # ... 省略
  # 定义一个反向引用，tag可以通过 post_set查询到 post的集合
  tags = db.relationship('Tag', secondary=post_tag,
              backref=db.backref('post_set', lazy='dynamic'))

class Tag(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  content = db.Column(db.String(10), unique=True)
  # 定义反向查询
  posts = db.relationship('Post', secondary=post_tag,
              backref=db.backref('tag_set', lazy='dynamic'))

  def __init__(self, content):
    self.content = content

  def save(self):
    db.session.add(self)
    db.session.commit()

>>> tag_list = []
>>> tags = ['python', 'flask', 'ruby', 'rails']
>>> for tag in tags:
    t = Tag(tag)
    tag_list.append(t)
>>> tag_list
[<f_sqlalchemy.Tag object at 0x0000000003B7CF28>, <f_sqlalchemy.Tag object at 0x0000000003B7CF98>, <f_sqlalchemy.Tag object at 0x0000000003B7CEB8>, <f_sqlalchemy.Tag object at 0x0000000003B7CE80>]
>>> p
<Post u'hello python'>
>>> p.tags
[]
>>> p.tags = tag_list  # 添加多对多的数据
>>> p.save()
>>> p.tags
[<f_sqlalchemy.Tag object at 0x0000000003B7CF28>, <f_sqlalchemy.Tag object at 0x0000000003B7CF98>, <f_sqlalchemy.Tag object at 0x0000000003B7CEB8>, <f_sqlalchemy.Tag object at 0x0000000003B7CE80>]
>>> p.tag_set      # 反向查询
<sqlalchemy.orm.dynamic.AppenderBaseQuery object at 0x0000000003B7C080>
>>> p.tag_set.all()
[<f_sqlalchemy.Tag object at 0x0000000003B7CF28>, <f_sqlalchemy.Tag object at 0x0000000003B7CF98>, <f_sqlalchemy.Tag object at 0x0000000003B7CEB8>, <f_sqlalchemy.Tag object at 0x0000000003B7CE80>]
>>> t = Tag.query.all()[1]
>>> t
<f_sqlalchemy.Tag object at 0x0000000003B7CF28>
>>> t.content
u'python'
>>> t.posts
[<Post u'hello python'>]
>>> t.post_set
<sqlalchemy.orm.dynamic.AppenderBaseQuery object at 0x0000000003B7C358>
>>> t.post_set.all()
[<Post u'hello python'>]
self one to one

class Category(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  name = db.Column(db.String(50))
  # 父级 id
  pid = db.Column(db.Integer, db.ForeignKey('category.id'))
  # 父栏目对象
  pcategory = db.relationship('Category', uselist=False, remote_side=[id], backref=db.backref('scategory', uselist=False))

  def __init__(self, name, pcategory=None):
    self.name = name
    self.pcategory = pcategory

  def __repr__(self):
    return '<Category %r>' % self.name

  def save(self):
    db.session.add(self)
    db.session.commit()

>>> p = Category('Python')
>>> p
<Category 'Python'>
>>> p.pid
>>> p.pcategory # 查询父栏目
>>> p.scategory # 查询子栏目
>>> f = Category('Flask', p)
>>> f.save()
>>> f
<Category u'Flask'>
>>> f.pid
1L
>>> f.pcategory # 查询父栏目
<Category u'Python'>
>>> f.scategory # 查询父栏目
>>> p.scategory # 查询子栏目
<Category u'Flask'>