flask使用sqlite数据库的连接

Flask web开发一书中，按照书上的代码一开始可以运行，但是在shell中进行数据库的修改，插入与删除时，在提交会话的时候会出现提示多线程的问题，这个问题的解决是在配置数据时便在原来的URI中加上?check_same_thread=False这句话，就可以了。

完整代码如下：

#数据库申明
basedir = os.path.abspath(os.path.dirname(__file__))
app.config['SQLALCHEMY_DATABASE_URI'] = \
    'sqlite:///' + os.path.join(basedir, 'data.sqlite')+'?check_same_thread=False'  
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False  
db = SQLAlchemy(app)  

#定义模型
class Role(db.Model): 
    __tablename__ = 'roles'  
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(64), unique=True)
    users = db.relationship('User', backref='role',lazy='dynamic')

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


class User(db.Model): 
    __tablename__ = 'users' 
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(64), unique=True, index=True)
    role_id = db.Column(db.Integer, db.ForeignKey('roles.id'))

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

#上下文处理器
@app.shell_context_processor
def make_shell_context():
    return dict(db=db,User=User,Role=Role)

#默认链接
@app.route('/',methods=['GET','POST'])
def index():
    form = NameFrom()
    if form.validate_on_submit():
        user = User.query.filter_by(username=form.name.data).first()
        if user is None:
            user = User(username=form.name.data)
            db.session.add(user)
            db.session.commit()
            session['known']=False
        else:
            session['known']=True
        session['name'] = form.name.data
        form.name.data=''
        return redirect(url_for('index'))
    return render_template('index.html',\
                           current_time=datetime.utcnow(),\
                           form=form,name=session.get('name'),\
                           known=session.get('known',False))

html如下：

index.html:

{% extends "base.html" %}

{% import "bootstrap/wtf.html" as wtf %}

{% block title %}Flasky{% endblock %}

{% block page_content %}
<div class="page-header">
    <h1>Hello,{% if name %}{{ name }}{% else %}Stranger{% endif %}!</h1>
    {% if not known %}
    <p>Pleased to meet you!</p>
    {% else %}
    <p>Happy to see you again!</p>
    {% endif %}
    <p>The local date and time is {{ moment(current_time).format('LLL') }}.</p>
    <p>That was {{ moment(current_time).fromNow(refresh=True) }}</p>
</div>
{{ wtf.quick_form(form) }}
{% endblock %}

base.html:

{% extends "bootstrap/base.html" %}

{% block title %}Flasky{% endblock %}

{% block head %}
{{ super() }}
<link rel="shortcut icon" href="{{ url_for('static', filename='favicon.ico') }}" type="image/x-icon">
<link rel="icon" href="{{ url_for('static', filename='favicon.ico') }}" type="image/x-icon">
{% endblock %}

{% block navbar %}
<div class="navbar navbar-inverse" role="navigation">
    <div class="container">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
            <a class="navbar-brand" href="/">Flasky</a>
        </div>
        <div class="navbar-collapse collapse">
            <ul class="nav navbar-nav">
                <li><a href="/">Home</a></li>
            </ul>
        </div>
    </div>
</div>
{% endblock %}

{% block content %}
<div class="container">
    {% for message in get_flashed_messages() %}
    <div class="alert alert-warning">
        <button type="button" class="close" data-dismiss="alert">&times;</button>
        {{ message }}
    </div>
    {% endfor %}

    {% block page_content %}{% endblock %}
</div>
{% endblock %}

{% block scripts %}
{{ super() }}
{{ moment.include_moment() }}
{% endblock %}