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复杂的MS Access Greatest-N-Per-Group问题（involved复杂的）

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在这里，我们将给大家分享关于复杂的MSAccessGreatest-N-Per-Group问题的知识，让您更了解involved复杂的的本质，同时也会涉及到如何更有效地(fields.E304)Rev

在这里，我们将给大家分享关于复杂的MS Access Greatest-N-Per-Group问题的知识，让您更了解involved复杂的的本质，同时也会涉及到如何更有效地(fields.E304) Reverse accessor for ''UserProfile.groups'' clashes with reverse accessor for...、5 Free Programs To Access Blocked US Online Stores、AccessType.FIELD，AccessType.PROPERTY和@Access的用途是什么、android – 执行aapt时出错：无法运行程序,CreateProcess error = 5,拒绝访问：CreateProcess error = 5,Access被拒绝的内容。

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复杂的MS Access Greatest-N-Per-Group问题（involved复杂的）

复杂的MS Access Greatest-N-Per-Group问题（involved复杂的）

我想将以下查询合并为一个，其中

  • scouting.jumpGate是整数，
  • scouting.astroLoc是一个字符串，
  • scouting.ownerguild是一个字符串，并且
  • scouting.galaxy是一个整数

交叉链接到另一个表（也是我的GROUP）：

    Select TOP 3         scouting.jumpGate,         scouting.astroLoc,         scouting.ownerGuild,         scouting.Galaxy FROM    scouting WHERE   scouting.Galaxy = 1 AND     scouting.ownerGuild = ''TEST'' ORDER BY    scouting.jumpGate DESC,             scouting.astroloc DESC;

和

    SELECT TOP 3         scouting.jumpGate,         scouting.astroLoc,         scouting.ownerGuild,         scouting.Galaxy FROM    scouting WHERE   scouting.Galaxy = 2 AND     scouting.ownerGuild = ''TEST'' ORDER BY    scouting.jumpGate DESC,             scouting.astroloc DESC;

和

    SELECT TOP 3         scouting.jumpGate,         scouting.astroLoc,         scouting.ownerGuild,         scouting.Galaxy FROM    scouting WHERE   scouting.Galaxy = 3 AND     scouting.ownerGuild = ''TEST'' ORDER BY    scouting.jumpGate DESC,             scouting.astroloc DESC;

持续到

    SELECT TOP 3         scouting.jumpGate,         scouting.astroLoc,         scouting.ownerGuild,         scouting.Galaxy FROM    scouting WHERE   scouting.Galaxy = 79 AND     scouting.ownerGuild = ''TEST'' ORDER BY    scouting.jumpGate DESC,             scouting.astroloc DESC;

在Microsoft网站上阅读此“每组最大N”问题后生成的代码如下：

Select  scouting.astroLoc,         scouting.galaxy,         scouting.jumpGate,         scouting.ownerGuild From    galaxy Inner Join         scouting On galaxy.[galaxy_ID] = scouting.galaxy Where   scouting.ownerGuild = ''SWARM'' AND     (scouting.jumpGate) In (Select Top 3 scouting.jumpGate From scouting Where scouting.galaxy = galaxy.[galaxy_ID] Order By scouting.jumpGate Desc) Order By    scouting.astroLoc Desc,             scouting.jumpGate Desc

基本上，这与我想要的非常接近。一切似乎都正常。但是，即使在盯着数据看之后，某些GROUPS仍未在输出中表示，每个组都有一条满足查询约束的记录。顺便说一句，如果我删除了scouting.ownerGuild=’SWARM’约束，它会很好地工作（但是我需要这个约束）。

答案1

小编典典

怎么样：

Select  scouting.astroLoc,         scouting.galaxy,         scouting.jumpGate,         scouting.ownerGuild From    galaxy Inner Join         scouting On galaxy.[galaxy_ID] = scouting.galaxy WHERE   (scouting.ID) In (             Select Top 3 scouting.ID             From scouting              Where scouting.galaxy = galaxy.[galaxy_ID]              And scouting.ownerGuild = ''SWARM''              Order By scouting.jumpGate Desc) Order By    scouting.astroLoc Desc,                 scouting.jumpGate Desc

否则，似乎前三名可能会包含一些

  where scouting.ownerGuild <> ''SWARM''

(fields.E304) Reverse accessor for ''UserProfile.groups'' clashes with reverse accessor for...

(fields.E304) Reverse accessor for ''UserProfile.groups'' clashes with reverse accessor for...

创建数据库models.py,在进行数据迁移时抛出一下异常:

E:\Project\GuoJia>python manage.py makemigrations
SystemCheckError: System check identified some issues:

ERRORS:
Fenxiao.UserProfile.groups: (fields.E304) Reverse accessor for ''UserProfile.groups'' clashes with reverse accessor for ''User.groups''.
        HINT: Add or change a related_name argument to the definition for ''UserProfile.groups'' or ''User.groups''.
Fenxiao.UserProfile.user_permissions: (fields.E304) Reverse accessor for ''UserProfile.user_permissions'' clashes with reverse accessor for ''User.user_permissions''.
        HINT: Add or change a related_name argument to the definition for ''UserProfile.user_permissions'' or ''User.user_permissions''.
auth.User.groups: (fields.E304) Reverse accessor for ''User.groups'' clashes with reverse accessor for ''UserProfile.groups''.
        HINT: Add or change a related_name argument to the definition for ''User.groups'' or ''UserProfile.groups''.
auth.User.user_permissions: (fields.E304) Reverse accessor for ''User.user_permissions'' clashes with reverse accessor for ''UserProfile.user_permissions''.
        HINT: Add or change a related_name argument to the definition for ''User.user_permissions'' or ''UserProfile.user_permissions''.

这是由于UserProfile扩展了内置的auth_user表，没有进行配置使用新定义的UserProfile表来做用户认证造成的异常

解决办法:

在settings.py中,添加使用UserProfile的配置选项: AUTH_USER_MODEL = "app名.扩展表的表明"

5 Free Programs To Access Blocked US Online Stores

5 Free Programs To Access Blocked US Online Stores

Ever wanted to do some online shopping only to find out that the online store does not allow you to access their website from a country outside of their own ? Many retailers (mainly from the United States or United Kingdom) do this; someti

ever wanted to do some online shopping only to find out that the online store does not allow you to access their website from a country outside of their own? many retailers (mainly from the united states or united kingdom) do this; sometimes you cannot browse the store products, while others don’t ship outside of the country.



(Image Source: Fotolia)

Well, in this mini-series we will teach you how to access, browse and shop from websites like these. In this first post, we’ll first show you how to browse these websites even if you aren’t within the country.

Editor’s Note: In future articles, we’ll give you some payment alternatives for when the website does not accept your local credit card and how to ship your purchases from the website to your doorstep when they do not offer international shipping.

Recommended Reading: 20+ Coupon Sites For The Best Shopping Deals And Bargains

1. TunnelBear

TunnelBear is a very simple to use program with an On/Off switch to surf on US or UK websites. Upon installation, you’ll have to register with an email address in order to start using it.

You’ll then have 500MB of free bandwidth to use per month (tracked by the program). This is plenty if you know what you want to buy and just want to click on that ‘Buy Now’ button.

Download: Windows | Mac | iOS | Android

TunnelBear

2. Tor Browser Bundle

The Tor Browser is a simple Firefox portable browser, modified with Tor to let you surf on websites that deny you access based on your location. Upon downloading the file and extracting its contents, just click on Start Tor Browser to begin surfing.

Don’t treat this as a replacement for your primary browser as the Tor Browser just allows basic usage without browser plugins.

Download: Windows | Mac | Linux

Tor Browser Bundle

3. HotspotShield

HotspotShield is a program that allows you to surf and shop on blocked sites. However, the free version is heavily ad-supported and you might have to click on some ads to continue surfing.

There is no registration required or bandwidth limitations. Once installed, it runs in the background and you can use your primary browser to surf.

Download: Windows | Mac | iOS | Android

HotspotSheild

4. PrivateTunnel

To download PrivateTunnel, you’ll have to first register for an account and download the program. You get 100MB monthly bandwidth but can earn more if you refer friends to get the program or when they make a purchase.

The program is easy to use and lets you surf on websites in the US, UK, Canada and Switzerland.

Download: Windows | Mac | iOS | Android

PrivateTunnel

5. OkayFreedom

You don’t have to register for an account if you can live with 500MB of bandwidth per month. However, you can earn 100 MB per recommendation and get a total of 1GB usage per month for free.

Once you’ve downloaded and installed the OkayFreedom, the icon sits on your PC taskbar for easy access. You can check how much you have used here. It allows you access to websites in the US, UK, Germany, France and Switzerland.

Download: Windows

OkayFreedom

Related posts:

  1. 5 Free Windows Programs To Monitor Your Internet Usage
  2. Organize Installed Programs On Windows 8 Modern UI Apps Menu Search
  3. How to Remotely Access Mac From Your Tablet
  4. 30 Online Stores To Shop For Geeky Gifts
5 Free Programs To Access Blocked US Online Stores

原文地址：5 Free Programs To Access Blocked US Online Stores, 感谢原作者分享。

AccessType.FIELD，AccessType.PROPERTY和@Access的用途是什么

AccessType.FIELD，AccessType.PROPERTY和@Access的用途是什么

我只想知道所有这些注释之间的区别。我们为什么使用这些…意味着它们没有任何作用，特别是在字段级别和属性级别上。

像这样使用混合级别注释的目的是什么：

@Entity@Access(AccessType.FIELD)class Employee {    // why their is a field level access     private int id;    // whats the purpose of transient here    @Transient                                   private String phnnumber;    // why its a property level access    @Access(AccessType.property)                 public String getPhnnumber() {        return "1234556";    }}

这堂课到底怎么说？

答案1

小编典典

默认情况下，访问类型由放置标识符注释（@Id）的位置定义。如果您将其放在场地上-
将会AccessType.FIELD，如果您将其放置在吸气剂上-
将会AccessType.PROPERTY。

有时，您可能不希望对字段进行注释，而要对属性进行注释（例如，因为您希望在getter中具有一些任意逻辑，或者因为您更喜欢这种方式。）在这种情况下，您必须定义getter并将其注释为AccessType.PROPERTY。

据我所记得，如果您指定任何一个AccessType.FIELD或AccessType.PROPERTY任何实体字段/方法，则必须指定整个类的默认行为。这就是为什么您需要AccessType.FIELD在类级别上进行设置（尽管这AccessType.FIELD是默认值）。

现在，如果你不会有@Transient对phnnumber领域，JPA会为您提供3列的表：

  • ID，
  • phnnumber，
  • getphnnumber。

这是因为它将AccessType.FIELD用于所有实体字段（id和phnnumber），同时将AccessType.PROPERTY用于getter（getPhnnumber()）。
您将在数据库中将电话号码映射两次。

因此，@Transient注释是必需的-这意味着实体不会将 字段 的值存储在基础存储中，而是将您的 getter
返回的值存储在基础存储中。

android – 执行aapt时出错：无法运行程序,CreateProcess error = 5,拒绝访问：CreateProcess error = 5,Access被拒绝

android – 执行aapt时出错：无法运行程序,CreateProcess error = 5,拒绝访问：CreateProcess error = 5,Access被拒绝

今天我刚刚使用Android SDK Manager更新了Windows 7上的Android SDK,并在Eclipse中构建期间开始出现错误

“Error executing aapt: Cannot run program … CreateProcess error=5,
Access is denied: CreateProcess error=5, Access is denied”

我正在使用Eclipse Juno和Kepler.我也尝试过Android SDK附带的捆绑Eclipse,但到处都遇到了同样的问题.

我正在使用Android构建工具版本18.0.1-

解决方法:

转到你的eclipse文件夹,打开eclipse.ini并添加这些行

-vm
C:\Program Files\Java\jdk1.6.0_29\jre\bin\server\jvm.dll

将jdk1.6.0_29替换为jdk的版本代码.这些行应在上面添加

-vmargs

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