Python具有对 SQlite 的内置支持. SQlite3模块附带Python发行版.有关在Python中使用SQLite数据库的详细教程。在本节中,我们将看到Flask应用程序如何与SQLite交互.
创建SQLite数据库'database.db'并在其中创建学生表.
import sqlite3 conn = sqlite3.connect('database.db') print "Opened database successfully"; conn.execute('CREATE TABLE students (name TEXT, addr TEXT, city TEXT, pin TEXT)') print "Table created successfully"; conn.close()
我们的Flask应用程序有三个 View 函数.
首先 new_student()函数绑定到URL规则('/addnew').它呈现一个包含学生信息表格的HTML文件.
@app.route('/enternew') def new_student(): return render_template('student.html')
'student.html'的HTML脚本如下 :
<html> <body> <form action = "{{ url_for('addrec') }}" method = "POST"> <h3>Student Information</h3> Name<br> <input type = "text" name = "nm" /></br> Address<br> <textarea name = "add" ></textarea><br> City<br> <input type = "text" name = "city" /><br> PINCODE<br> <input type = "text" name = "pin" /><br> <input type = "submit" value = "submit" /><br> </form> </body> </html>
可以看出,表单数据被发布到'/addrec' URL,该URL绑定 addrec( )功能.
这个 addrec()函数通过 POST 方法检索表单的数据并插入学生表中.与插入操作中的成功或错误相对应的消息呈现给'result.html'.
@app.route('/addrec',methods = ['POST', 'GET']) def addrec(): if request.method == 'POST': try: nm = request.form['nm'] addr = request.form['add'] city = request.form['city'] pin = request.form['pin'] with sql.connect("database.db") as con: cur = con.cursor() cur.execute("INSERT INTO students (name,addr,city,pin) VALUES (?,?,?,?)",(nm,addr,city,pin) ) con.commit() msg = "Record successfully added" except: con.rollback() msg = "error in insert operation" finally: return render_template("result.html",msg = msg) con.close()
result.html 的HTML脚本包含一个转义语句 {{msg}} 显示插入操作的结果.
<!doctype html> <html> <body> result of addition : {{ msg }} <h2><a href = ">go back to home page</a></h2> </body> </html>
该应用程序包含另一个由'/list' URL表示的 list()函数.它将'rows'填充为包含学生表中所有记录的 MultiDict 对象.此对象将传递到 list.html 模板.
@app.route('/list') def list(): con = sql.connect("database.db") con.row_factory = sql.Row cur = con.cursor() cur.execute("select * from students") rows = cur.fetchall(); return render_template("list.html",rows = rows)
此 list.html 是一个模板,迭代行集并在HTML表格中呈现数据.
<!doctype html> <html> <body> <table border = 1> <thead> <td>Name</td> <td>Address>/td< <td>city</td> <td>Pincode</td> </thead> {% for row in rows %} <tr> <td>{{row["name"]}}</td> <td>{{row["addr"]}}</td> <td> {{ row["city"]}}</td> <td>{{row['pin']}}</td> </tr> {% endfor %} </table> <a href = "/">Go back to home page</a> </body> </html>
最后,'/'网址规则会显示'home.html'应用程序的入口点.
@app.route('/') def home(): return render_template('home.html')
以下是 Flask-SQLite 应用程序的完整代码.
from flask import Flask, render_template, request import sqlite3 as sql app = Flask(__name__) @app.route('/') def home(): return render_template('home.html') @app.route('/enternew') def new_student(): return render_template('student.html') @app.route('/addrec',methods = ['POST', 'GET']) def addrec(): if request.method == 'POST': try: nm = request.form['nm'] addr = request.form['add'] city = request.form['city'] pin = request.form['pin'] with sql.connect("database.db") as con: cur = con.cursor() cur.execute("INSERT INTO students (name,addr,city,pin) VALUES (?,?,?,?)",(nm,addr,city,pin) ) con.commit() msg = "Record successfully added" except: con.rollback() msg = "error in insert operation" finally: return render_template("result.html",msg = msg) con.close() @app.route('/list') def list(): con = sql.connect("database.db") con.row_factory = sql.Row cur = con.cursor() cur.execute("select * from students") rows = cur.fetchall(); return render_template("list.html",rows = rows) if __name__ == '__main__': app.run(debug = True)
从Python shell运行此脚本,并且开发服务器开始运行.在浏览器中访问 http://localhost:5000/,显示一个简单的菜单,如下所示;
点击'添加新记录'链接以打开学生信息表格.
填写表单字段并提交.底层函数将记录插入学生表中.
返回主页并单击'显示列表'链接.将显示显示样本数据的表格.