• Django 数据库查询


    #!/usr/bin/python
    #coding:utf-8
    
    from django.shortcuts import render;
    from django.shortcuts import render_to_response;
    from django.http import HttpResponse;
    from django.template import loader,Context, Template;
    from django.http import HttpResponseRedirect;
    from django.views.decorators.csrf import csrf_exempt;
    import time, datetime;
    from django.db import connection,transaction;
    
    from blog.models import Blog;
    from blog.models import Entry;
    from blog.models import Author;
    from blog.models import AuthorBlog;
    
    
    def saveBlog(request):
        try:
            blog=Blog();
            blog.name="python";
            blog.tagline="Python是一种解释型、面向对象、动态数据类型的高级程序设计语言。自从20世纪90年代初Python语言诞生至今,它逐渐被广泛应用于处理系统管理任务和Web编程。";
            blog.save();
            return HttpResponse("save blog success");
        except BaseException, e:
            return HttpResponse("save blog failure:"+e);
            
    def updateBlog(request):
        try:
            blog=Blog.objects.get(id=4);
            blog.tagline="Python是一种解释型、面向对象、动态数据类型的高级程序设计语言。";
            blog.save();
            return HttpResponse("update blog success");
        except BaseException, e:
            return HttpResponse("update blog failure:"+e);
    
    def delBlog(request):
        try:
            blog=Blog.objects.get(id=4);
            #blog.delete();
            return HttpResponse("delete blog success");
        except BaseException, e:
            return HttpResponse("delete blog failure:"+e);
    
    ###一对多添加###
    def saveEntry(request):
        try:
            blog=Blog.objects.get(id=4); #python
            entry=Entry();   
            entry.headline="django";
            entry.body_text="Django是一个开放源代码的Web应用框架,由Python写成。";
            entry.pub_date=datetime.date.today();
            entry.blog=blog;
            entry.save();
            return HttpResponse("save entry success");
        except BaseException, e:
            return HttpResponse("save entry failure:"+e);
    
    ###多对多添加###
    def saveAuthorBlog(request):
        try:
            author=Author.objects.get(id=1);
            blog=Blog.objects.get(id=4);
            ab=AuthorBlog();
            ab.author=author;
            ab.blog=blog;
            ab.created_at=datetime.date.today();
            ab.save();
            return HttpResponse("save AuthorBlog success");
        except BaseException, e:
            return HttpResponse("save AuthorBlog failure:"+e);
          
    def queryBlog(request):
        #检索所有的对象
        blogs = Blog.objects.all();
        for blog in blogs:
            print blog.name;
        print "=======";
        
        #多对一查询
        entrys=Entry.objects.all();
        for entry in entrys:
            print entry.headline+", "+entry.blog.id+", "+entry.blog.name;
        print "=======";
        
        return HttpResponse("queryBlog");
        
    ###执行原生查询并返回模型实例###
    def rawBlog(request):
        raw_sql = 'select * from blog_Blog';
        blogs=Blog.objects.raw(raw_sql); #xx.objects.raw()执行原始sql
        print blogs;
        for blog in blogs:
            print blog.name;
        print "======";
        
        raw_sql = 'select * from blog_Blog o where o.name=%s'; #带参数
        blogs=Blog.objects.raw(raw_sql, ["j2ee"]); #xx.objects.raw()执行原始sql
        print blogs;
        for blog in blogs:
            print blog.name;
        return HttpResponse("rawBlog");
        
    def sqlBlog(request):
        cursor=connection.cursor(); #获得一个游标(cursor)对象
        
        #更新操作
        cursor.execute('update blog_Blog set name="hadoop168" where id=%s', [1]); #执行sql语句
        transaction.commit_unless_managed(); #提交到数据库
        
        #查询操作
        cursor.execute('select * from blog_Blog where id=%s', [1]);
        blogs = cursor.fetchone(); #或使用 #raw = cursor.fetchall();返回的结果集是个元组
        for blog in blogs:
            print blog;
        print "======";
        
        cursor.execute('select * from blog_Blog');
        blogs = cursor.fetchall(); #返回的结果集是个元组
        for blog in list(blogs):
            print str(blog[0])+", "+blog[1]+", "+blog[2];
        print "======";
        
        return HttpResponse("sqlBlog");
    
    def querySqlBlog(request):
        sql="select b.name as blog_name, e.headline from blog_Blog b, blog_Entry e where b.id=e.blog_id";
        cursor=connection.cursor(); #获得一个游标(cursor)对象
        cursor.execute(sql);
        blogs = cursor.fetchall(); #返回的结果集是个元组
        
        records=[]
        for blog in blogs:
            dic={}
            dic['blog_name']=blog[0]
            dic['headline']=blog[1]
            records.append(dic);
        
        for record in records:
            print record["blog_name"]+", "+record["headline"];
        return HttpResponse("sqlBlog");
        
    def searchBlog(request):
        #检索所有的对象
        #blogs = Blog.objects.all(); #使用all()方法返回数据库中的所有对象
        
        #检索特定的对象,使用以下两种方法: 
        #fileter()  返回一个与参数匹配的QuerySet,相当于等于(=)
        #exclude()  返回一个与参数不匹配的QuerySet,相当于不等于(!=)
        
        #blogs=Blog.objects.filter(name='python'); 等同于:slect * from blog_Blog where name='python' 
        #不使用Blog.objects.all().filter(name='python'),虽然也能运行,all()最好再获取所有的对象时使用。 
        blogs=Blog.objects.filter(name='python');
        for blog in list(blogs):
            print str(blog.id)+", "+blog.name+", "+blog.tagline;
        print "======";
        
        return HttpResponse("searchBlog");
        
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  • 原文地址:https://www.cnblogs.com/chengJAVA/p/4432053.html
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