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MySQL中的自动递增问题

数据库中主键设置自动递增以后，下一个的大小取决于你在数据库中操作过得数据量的大小，假如你的数据库中只有10个数据，但是未必下一个数据就可以如愿变成11，因为下一个数字的大小在于你的数据库“ 流通过的”数据，比如你往数据库里面添加过120个数据，但是你删了110，那么你再添加数据，就会变成第121个，这个可以在表设置主键那里自行查看或更改。

Results问题

results.form.get('name')
results.form['name']

两者一般情况下是没有区别的，目的都是为了从模板中获取数据，获取数据的开源就是根据在模板中制定的‘name’来获取数据；

代码

from flask import Flask, render_template,request,redirect,url_for,json
import pymysql
from flask_cors import *

app = Flask(__name__)
CORS(app, supports_credentials = True)
# 连接数据库的四个要素（端口号默认3306，已省略）
hostName = "localhost"
userName = "root"
userPassword = "root"
dbName = "study11"

#路由默认只支持get，如果需要增加，需要自行指定
#书目检索表的建立和书表格
@app.route("/lib",methods=['GET','POST'])
def index():
# 使用connect方法进行连接MySQL
# 函数
db = pymysql.connect(hostName, userName, userPassword, dbName)
# 我们需要一个游标
cursor = db.cursor()
# 编写SQL
sql = "select * from imd_book"
# sql = """insert into imd_book (isdn,publish_date,author,publisher,name,bookid)
# values ('188XXX188','2007/2/3','施耐庵','中国出版社','水浒传',21)"""
#sql = "delete from imd_book where bookid=17"
#馆藏副本总数
sql1 = "select count(*) from imd_copybook where book_id = %s"
#馆藏可借总数  is_borrow=1可借 stautus=1未被借走
sql2 = "select count(*) from imd_copybook where is_borrow=1 and status=1 and book_id= %s"
try:
# 执行SQL，使用execute方法执行
cursor.execute(sql)
# 获取数据
results = cursor.fetchall()
#print(results)
# 循环显示数据
datalist = []
for row in results:
#每一次循环都把one列表变成空列表
one = []
#把第一本书的所有数据放在one这个列表中
one.append(row[0])
one.append(row[1])
one.append(row[2])
one.append(row[3])
one.append(row[4])
one.append(row[5])
#通过sql1和书的id去imd_copybook表中查询书的总数量
cursor.execute(sql1, [row[5]])
#把该id的书的所有馆藏副本数量赋给results1
results1 = cursor.fetchone()
#print (results1)
#再把这个数据加入到one这个列表中
one.append(results1[0])
#print (one)
#执行sql2，获取可以借阅到的副本数量
cursor.execute(sql2,[row[5]])
#把该值赋给results2
results2 = cursor.fetchone()
#再加入到one列表中
one.append(results2[0])
#把整个one列表加入到datalist空列表中
datalist.append(one)
except:
print("error")
#检索图书
if request.method == 'POST':
# 获取想要的参数
#print (request.form['f'])
#print (name_key)
sql3 = sql + " where " + request.form['f'] + " like '%{}%'"
sql3 = sql3.format(request.form.get('key'))
#print (sql3)
sql4 = "select count(*) from imd_copybook where book_id = %s"
sql5 = "select count(*) from imd_copybook where is_borrow=1 and status=1 and book_id= %s"
datalist_two = []
try:
#查询书本信息
cursor.execute(sql3)
results3 = cursor.fetchall()
#print (results3[0])
two = []
for row_one in results3[0]:
two.append(row_one)
#print(two)
#查询馆藏数量
cursor.execute(sql4,two[5])
results4 = cursor.fetchone()
#print(results4)
#查询可借数量
cursor.execute(sql5, two[5])
results5 = cursor.fetchone()
#print(results5)
two.append(results4[0])
two.append(results5[0])
#数据导入列表
datalist_two.append(two)
#print (datalist_two)
except:
print("error")
return render_template('lib.html', datalist=datalist_two)
# 关闭游标
cursor.close()
# 关闭数据库
db.close()
return render_template('lib.html',datalist = datalist)

@app.route("/book/<id>")
def book(id):
#1、通过主键获取书的信息
sql1 = "select * from imd_book where book_id={}"
sql1 = sql1.format(id)
#2、查询馆藏书
sql2 ="select count(*) from imd_copybook where book_id={}"
sql2 = sql2.format(id)
#3、查询可借复本数
sql3 = "select count(*) from imd_copybook where status = 1 and is_borrow = 1 and book_id = {}"
sql3 = sql3.format(id)
#4、借阅记录数
sql4 = "select count(*) from imd_record a left join imd_copybook b on a.copy_id=b.copybookid" \
" where b.book_id={}"
sql4 = sql4.format(id)
#5、借阅记录
sql5 = "select a.*,c.* from imd_record a " \
"left join imd_user c on a.user_id = c.user_id " \
"left join imd_copybook b on a.copy_id = b.copybookid " \
"where b.book_id = {}"
sql5 = sql5.format(id)
#6、书的平均评分
sql6 = "select avg(a.score) from imd_comment a left join imd_copybook b on a.copy_id=b.copybookid" \
" where b.book_id={}"
sql6 = sql6.format(id)
#7、书的评分及评论记录
sql7 = "select a.*,c.* from imd_comment a " \
"left join imd_user c on a.user_id = c.user_id " \
"left join imd_copybook b on a.copy_id = b.copybookid " \
" where b.book_id = {}"
sql7 = sql7.format(id)
#8、书的评论总记录数
sql8 = "select count(*) from imd_comment a left join imd_copybook b on a.copy_id=b.copybookid" \
" where b.book_id={}"
sql8 = sql8.format(id)
#9、查询副本状态
sql9 = "select * from imd_copybook where book_id={}"
sql9 = sql9.format(id)

db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
datalist = []
try:
one = []
#print (sql1)
cursor.execute(sql1)
results1 = cursor.fetchall()
#print (results1)
for row in results1:
one.append(row[0])
one.append(row[1])
one.append(row[2])
one.append(row[3])
one.append(row[4])
one.append(row[5])
#print (one)
#print(sql2)
cursor.execute(sql2)
results2 = cursor.fetchone()
#print (results2)
one.append(results2[0])
#print(one)
#print(sql3)
cursor.execute(sql3)
results3 = cursor.fetchone()
#print(results3)
one.append(results3[0])
#print(one)
#print(sql4)
cursor.execute(sql4)
results4 = cursor.fetchone()
#print(results4)
#print(sql5)
cursor.execute(sql5)
results5 = cursor.fetchall()
#print(results5)
#print(sql6)
cursor.execute(sql6)
results6 = cursor.fetchone()
#print (results6)
#print(sql7)
cursor.execute(sql7)
results7 = cursor.fetchall()
#print(results7)
#print(sql8)
cursor.execute(sql8)
results8 = cursor.fetchall()
#print(results8)
cursor.execute(sql9)
results9 = cursor.fetchall()
#print (results9)
except:
print ("error")
datalist.append(one)
#print (datalist)
cursor.close()
db.close()
return render_template("2.html",re4 = results4,datalist = datalist,re5 = results5,re6 = results6,re7 = results7,re8 = results8,re9 = results9)

@app.route("/2")
def rrrrr():
return render_template("2.html")

#添加图书，直接跳转到添加书的页面，点击提交按钮后，跳转到savebook
@app.route("/addBook")
def add_Book():
return render_template('add_book.html')
#与数据库对接，有了添加图书的基本信息后添加到数据库中，并转到最初的index（书表）中
@app.route("/saveBook",methods=['GET','POST'])
def saveBook():
#1.获取数据
# print (request.form['name'])
# print (request.form['author'])
# print (request.form['publisher'])
# print (request.form['isbn'])
# print (request.form['publishDate'])

#2.拼写sql
sql = "insert into imd_book (name,author,publisher,isbn,publish_date)" \
" values ('{}','{}','{}','{}','{}')"

sql = sql.format(request.form['name'],request.form['author'],request.form['publisher'],
request.form['isbn'],request.form['publishDate'])
#print (sql)
#3.连接数据库
db = pymysql.connect(hostName, userName, userPassword, dbName)

#4.获取游标，执行sql
cursor = db.cursor()
try:
cursor.execute (sql)
except:
print ("error")

#5.关闭游标，关闭数据库
cursor.close()
db.close()

#7.重定向或跳转
return redirect(url_for("listBook"))
#删除图书，这一步的目的是获取要删除的书的编号
@app.route ("/delBook")
def delBook():
#获取数据，表示get方式来获取内容，直接获取id后下面可以直接使用
id = request.args.get('id')
return id
#获取到书的编号，与数据库对接，并执行删除书的操作，并返回到管理员的书的展示页面
@app.route ("/delBook/<id>")
def delBook2(id):
sql = "delete from imd_book where bookid = {}"
sql = sql.format(id)
db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
cursor.execute(sql)
except:
print ("error")
cursor.close()
db.close()
return redirect(url_for('listBook'))
#更改图书
@app.route("/updateBook",methods=['GET','POST'])
def updateBook():
#获取数据：
bookid = request.form['bookid']
name = request.form['name']
publisher = request.form['publisher']
publishDate = request.form['publishDate']
isbn = request.form['isbn']
author = request.form['author']
sql = "update imd_book set bookid={},name='{}',publisher='{}',publish_date='{}',isbn='{}',author='{}' where book_id={}"
sql = sql.format(bookid,name,publisher,publishDate,isbn,author,bookid)
db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
print (sql)
cursor.execute(sql)
except:
print("error")
cursor.close()
db.close()
return redirect(url_for('listBook'))
#管理员界面，在该页面可以对书进行直接操作
@app.route("/listBook")
def listBook():
#1.获取参数
#2.拼写sql
sql = "select * from imd_book"
#3.连接数据库
db = pymysql.connect(hostName, userName, userPassword, dbName)
#4.获取游标，执行sql
cursor = db.cursor()
try:
cursor.execute(sql)
results = cursor.fetchall()
except:
print ("error")
#5.关闭游标，关闭数据库
cursor.close()
db.close()
#6.重定向或跳转
return render_template("list.html",re = results)
#展示单一的一本书，并对这本书执行相关操作
@app.route("/showBook/<id>")
def showBook(id):
sql = "select * from imd_book where book_id = {}"
sql = sql.format(id)
db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
#print (sql)
cursor.execute(sql)
results = cursor.fetchall()
#print (results)
except:
print ("error")
cursor.close
db.close()
return render_template("show_book.html",re = results)
#对图书的副本情况的展示
@app.route("/listCopyBook/<id>")
def listCopyBook(id):
sql = "select * from imd_copybook where book_id={}"
sql = sql.format(id)

sql2 = "select * from imd_book where book_id={}"
sql2 = sql2.format(id)

db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
#print (sql)
cursor.execute(sql)
results = cursor.fetchall()
#print (results)
#print (sql2)
cursor.execute(sql2)
book = cursor.fetchone()
#print (book)
except:
print ("error")
cursor.close()
db.close()
return render_template("listCopyBook.html",book = book,rs = results)
#对一个副本的展示
@app.route("/showCopyBook/<copybookid>")
def showCopyBook(copybookid):
sql = "select * from imd_copybook where copybookid = '{}'"
sql = sql.format(copybookid)
db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
#print (sql)
cursor.execute(sql)

results = cursor.fetchall()
#print (results)
except:
print ("error")
cursor.close
db.close()
return render_template("showCopyBook.html",re = results)

#对图书副本进行添加操作
@app.route("/addCopyBook")
def addCopyBook():
return render_template("addCopyBook.html")
#跳转页面后执行下面函数来进行操作并跳转到listCopyBook页面
@app.route("/saveCopyBook",methods=['GET','POST'])
def saveCopyBook():
id = request.form['bookid']
sql = "insert into imd_copybook (place,status,is_borrow,copybookid,book_id) values('{}','{}','{}','{}','{}')"
sql = sql.format(request.form['place'],request.form['status'],request.form['is_borrow'],request.form['copybookid'],request.form['bookid'])

sql2 = "select * from imd_book where book_id = {}"
sql2 = sql2.format(id)

sql3 = "select * from imd_copybook where book_id={}"
sql3 = sql3.format(id)

db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
cursor.execute(sql)
#print (sql)
cursor.execute(sql2)
#print (sql2)
book = cursor.fetchone()
#print (book)
cursor.execute (sql3)
#print (sql3)
results = cursor.fetchall()
#print (results)
except:
print ("error")
cursor.close()
db.close()
return render_template("listCopyBook.html",book = book,rs = results)

#对图书副本执行修改操作
@app.route("/updateCopyBook",methods=['GET','POST'])
def updateCopyBook():
copybookid = request.form['copybookid']
place = request.form['place']
status = request.form['status']
is_borrow = request.form['is_borrow']
id = request.form['bookid']

sql = "update imd_copybook set place='{}',copybookid='{}',status='{}',is_borrow='{}' where copybookid='{}'"
sql = sql.format(place,copybookid,status,is_borrow,copybookid)
print(sql)
db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()

try:
cursor.execute(sql)
except:
print ("error")
cursor.close()
db.close()
return redirect(url_for("listCopyBook",id=id))

#对图书副本执行删除操作
@app.route("/delCopyBook/<copybookid>")
def delCopyBook(copybookid):
sql = "delete from imd_copybook where copybookid='{}'"
sql = sql.format(copybookid)
db = pymysql.connect( hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
#print (sql)
cursor.execute(sql)
except:
print("error")
cursor.close()
db.close()
return redirect(url_for("listBook"))

@app.route("/bookListJson")
def bookListJson():
#获取参数
# 拼写sql
sql = "select * from imd_book"
# 连接数据库
db = pymysql.connect(hostName,userName,userPassword,dbName)
# 获取游标，执行sql
cursor = db.cursor()
try:
cursor.execute(sql)
results = cursor.fetchall()
except:
print ("error")
# 关闭游标，关闭数据库
cursor.close()
db.close()
# 跳转或重定向输出json
return json.dumps(results,ensure_ascii=False)

@app.route("/bookShowJson")
def bookShowJson():
id = request.args.get('id')
sql = "select * from imd_book where book_id = {}"
sql = sql.format(id)
db = pymysql.connect(hostName, userName, userPassword, dbName)
cursor = db.cursor()
try:
print(sql)
cursor.execute(sql)
results = cursor.fetchone()
except:
print("error")
cursor.close()
db.close()
return json.dumps(results, ensure_ascii=False)

if __name__ == '__main__':
app.run(host="0.0.0.0")

其中有一部分代码的目的是通过Json传递数据，实现前后端分离；

思路体现（有一个好得逻辑性很重要，最好整理下来，敲代码也方便）

下面这张图片就是我在做这个系统时所整理的思路（比较乱，但是我好歹还可以看懂）

浏览器返回400的错误

这样的错误一般都是出现在前后端数据不一致时，这时候需要检查的是sql语句和Python从数据库里面爬取到的数据有没有问题，大部分是在后端，因为后端比较乱，容易出错，可以让Python运行后输出sql语句，粘贴到数据库查询中来检查sql语句是否有误，因为Python并不会报数据库的错误；而如果数据没有问题，那么需要做的就是检查设置的变量是否有问题；

vue遇到的问题整理

1.在vue中，一次只可以运行一个标签，所以如果想要同时运行多个标签，不要忘记给整体加上一个

标签，这样做的目的就是让特曼同级。
2.如果报错信息显示，在xx.vue文件里，“Vue”定义了但是没有使用，那么大胆的注释掉就OK！