用Flask框架作兩個關聯式的下拉式選單，抓取資料庫資料

flask 雙關聯式下拉式

toru0516 2018-06-05 21:28:31 ‧ 4388 瀏覽

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各位iT邦前輩們，晚安，先前依照某iT邦大提供的方法，做好一個下拉式選單連接資料庫，但是如果要作成雙關聯下拉式，選取好之後按鈕，再從資料庫抓取資料，卻一直沒辦法，資料庫如下：

ID	Model_Name	value_without	time
0050	Multiple Regression	0.5781	13.03
0050	Logistic Regression	0.587	10.93
0051	Multiple Regression	0.5158	10.98
0051	Logistic Regression	0.572	10.16
0052	Multiple Regression	0.5734	14.67
0052	Logistic Regression	0.5396	12.42

目前寫好的Python：

class ETL(db.Model):
    tablename = 'etl1'
    ID = db.Column(db.Float)
    Model_Name = db.Column(db.String(255))
    value_without = db.Column(db.Float)
    time = db.Column(db.Float)

@app.route('/',  methods=['GET', 'POST'])
def index():
    etl1s = ETL.query.all()
    if 'eid' in request.form:
        eid = request.form.get('eid' ,type=float)
        step1 = ETL.query.get(eid)
        return render_template("index.html", etl1s=etl1s, step1=step1)
    return render_template("index.html", etl1s=etl1s)

HTML：

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>ETL_SQL</title>
</head>
<body>

<form method="POST">
    <select name="eid" id="eid">
        <option value="0050">0050</option>
        <option value="0051">0051</option>
        <option value="0052">0052</option>
    </select>
    <br>
    <input type="submit" value="Search" onClick="windows.location.reload()">
    <br>
</form>

{% if step1 %}
    <div>ID：{{step1.ID}}</div>
    <div>Model Name：{{step1.Model_Name}}</div>
    <div>Value Without：{{step1.value_without}}</div>
    <div>Time：{{step1.time}}</div>
{% endif %}
</body>
</html>

現在問題想要作成兩個關聯式下拉式選單，也就是在網頁中讓使用者下拉式選擇欄位ID，再選擇Model_Name，然後按按鈕做確認，從資料庫抓取所選擇的ID、Model_Name、value_without及time欄位資料，那麼在Python及HTML及要多加那些語法，懇請IT邦大大們解法，謝謝。

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黃彥儒 iT邦高手 1 級 ‧ 2018-06-05 22:41:42 檢舉

ajax

froce iT邦大師 1 級 ‧ 2018-06-05 23:46:21 檢舉

他要的根本不用兩段式啊，對欄位取distinct取得所有選項，一次送出就好。

paicheng0111 iT邦大師 5 級 ‧ 2018-06-06 10:38:57 檢舉

你有import了那些庫？

froce iT邦大師 1 級 ‧ 2018-06-06 11:35:35 檢舉

他要的只需要這兩個：
from flask import Flask, render_template, request
from flask_sqlalchemy import SQLAlchemy

不過 SQLAlchemy 語法我覺得好囉唆，不用Django ORM的話，乾脆寫SQL還比較快。

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1 個回答

froce

iT邦大師 1 級 ‧ 2018-06-05 23:45:10

唉，自己看吧。這個很基本。

from flask import Flask, render_template, request
from flask_sqlalchemy import SQLAlchemy
import os

app = Flask(__name__)
db_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "test.db")
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////{}'.format(db_path)
db = SQLAlchemy(app)


class ExamData(db.Model):
    tablename = 'ExamData'
    id = db.Column(db.Integer, primary_key=True)
    eid = db.Column(db.Integer)
    model_Name = db.Column(db.String(255))
    value_without = db.Column(db.Float)
    time = db.Column(db.Float)


@app.route('/', methods=['GET', 'POST'])
def all_persons():
    EID = db.session.query(ExamData.eid).distinct()  # 取得所有EID
    model_Name = db.session.query(ExamData.model_Name).distinct()  # 取得所有model_Name
    if 'eid' in request.form and 'model_Name' in request.form:
        result = ExamData.query.filter_by(eid=int(request.form.get("eid")), model_Name=request.form.get("model_Name"))
        return render_template("index.html", EID=EID, model_Name=model_Name, result=result)
    return render_template("index.html", EID=EID, model_Name=model_Name)



if __name__ == '__main__':
    if not os.path.exists(db_path):
        db.create_all()
        db.session.add(ExamData(eid=50, model_Name='Multiple Regression', 
                        value_without=0.5781, time=13.03))
        db.session.add(ExamData(eid=50, model_Name='Logistic Regression',
                        value_without=0.587, time=10.93))
        db.session.add(ExamData(eid=51, model_Name='Multiple Regression',
                        value_without=0.5158, time=10.98))
        db.session.add(ExamData(eid=51, model_Name='Logistic Regression',
                        value_without=0.572, time=10.16))

        db.session.commit()

    app.run()

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="https://code.jquery.com/jquery-3.3.1.min.js" integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8="
        crossorigin="anonymous"></script>
</head>
<body>
    <form method="POST">
        <select name="eid">
            {% for e in EID %}
            <option>{{ e.eid }}</option>
            {% endfor %}
        </select>
        <select name="model_Name">
            {% for m in model_Name %}
            <option>{{ m.model_Name }}</option>
            {% endfor %}
        </select>
        <input type="submit" value="送出" id="btn">
    </form>
    {% for r in result %}
    <div>{{ r.eid }}</div>
    <div>{{ r.model_Name }}</div>
    <div>{{ r.value_without }}</div>
    <div>{{ r.time }}</div>
    {% endfor %}
</body>
</html>