Question

我正在尝试升级我的方式从mysql从mysqli_query获取到fetchall。

$res = mysqli_query($db, "SELECT * FROM forum_index WHERE forum_over='yes'");
        while ($arr = mysqli_fetch_assoc($res)) {
        ......
    }

所以当我使用fetchAll（）时，我会得到一个数组，我应该使用foreach（），还是有更智能的方法呢？

要从数据库中收集单个值，这是正确的方法吗？

$fid = (int)$_GET['id'];
$thread = $db->query("SELECT * FROM forum_threads WHERE f_id=".$fid)->fetch_array();
    echo $thread['id'];

Answer 1

您不需要仅仅因为您正在使用PDO而使用import os, sys from flask import Flask, render_template, flash, request, url_for, redirect, session, send_file, send_from_directory # WTForms from wtforms import Form, BooleanField, TextField, PasswordField, SelectField, RadioField, TextAreaField, DateField, DateTimeField, StringField, validators from wtforms.widgets import TextArea from wtforms.validators import DataRequired from flask_wtf import FlaskForm, RecaptchaField from flask_wtf.file import FileField, FileRequired, FileAllowed from werkzeug.utils import secure_filename from flask_uploads import UploadSet, configure_uploads, IMAGES, patch_request_class from MySQLdb import escape_string as thwart app = Flask(__name__) #### PROFILE PIC UPLOAD #### # Based after https://gist.github.com/greyli/81d7e5ae6c9baf7f6cdfbf64e8a7c037 # For uploading files PROF_PIC_UPLOAD_FOLDER = 'static/user_info/prof_pic' ALLOWED_EXTENSIONS = set(['png', 'jpg', 'jpeg', 'gif']) app.config['UPLOADED_PHOTOS_DEST'] = os.getcwd() photos = UploadSet('photos', IMAGES) configure_uploads(app, photos) patch_request_class(app) # set maximum file size, default is 16MB class ProfilePictureForm(FlaskForm): prof_pic = FileField(validators=[FileAllowed(photos, u'Image only!')]) @app.route('/profile_picture_upload/', methods=['GET','POST']) def profile_picture_upload(): form = ProfilePictureForm() cid = str(session['clientcid']) first_name = session['first_name'] static_url = url_for('static', filename='user_info/prof_pic/') default_prof_pic = 'http://localhost:5000/_uploads/photos/static/user_info/prof_pic/default.jpg' user_prof_pic = cid+first_name+'.png' if form.validate_on_submit(): filename = photos.save(form.prof_pic.data, folder=PROF_PIC_UPLOAD_FOLDER,name=cid+first_name+'.png') file_url = photos.url(filename) # Checks if the prof_pic is set yet. if set, then dont need to delete the old picture on the server if session['prof_pic'] != 'http://localhost:5000/_uploads/photos/static/user_info/prof_pic/default.jpg': #need to delete or move the old prof_pic if it was set! Prevents users from adding too many pictures flash("You already have a file on the server!") #If the user_prof_pic is there, then session['prof_pic'] = file_url c, conn = connection() c.execute("UPDATE cpersonals SET prof_pic = %s WHERE cid = (%s)", (file_url, cid)) conn.commit() c.close() conn.close() else: file_url = None return render_template('profile_picture_upload.html', form=form, file_url=file_url)。如果查询返回大量数据，这可能会减慢速度，因为它必须将所有数据全部收集到内存中。您可以使用与mysqli代码中相同类型的循环：

fetchAll()

关于第二个问题，你应该使用参数化查询，而不是替换变量。

$res = $pdo->query("SELECT * FROM forum_index WHERE forum_over='yes'");
while ($row = $res->fetch(PDO::FETCH_ASSOC)) {
    ...
}

mysqli_query while循环到PDO

1 个答案: