uuid | 易学教程

How to generate uuid with PostgreSQL 8.4.4 on Ubuntu 10.04?

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问题 I am running PostgreSQL 8.4.4 with Ubuntu 10.04. I am trying to generate uuid but can't find a way to do it. I do have the uuid-ossp.sql in /usr/share/postgresql/8.4/contrib/uuid-ossp.sql When I try this is what I get : postgres=# SELECT uuid_generate_v1(); ERROR: function uuid_generate_v1() does not exist LINE 1: SELECT uuid_generate_v1(); ^ HINT: No function matches the given name and argument types. You might need to add explicit type casts. Any idea ? 回答1: The stuff in contrib aren't run

how to insert a record with a uuid array into a pg table using nodejs pg-promise library

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问题 i need to have a table in my db which contains a single column which is an array of uuid objects (uuid[] type) but when i try to insert into it using a nodejs library named pg-promise it fails i get the following error message telling me i need to rewrite the cast or the expression {"name":"error","length":206,"severity":"ERROR","code":"42804","hint":"You will need to rewrite or cast the expression.","position":"230","file":"src\\backend\\parse r\\parse_target.c","line":"510","routine":

When is it appropriate to use UUIDs for a web project?

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问题 I'm busy with the database design of a new project, and I'm not sure whether to use UUIDs or normal table-unique auto-increment ids. Up to now, the sites I've built have all run on a single server, and very heavy traffic has never been too much of a concern. However, this web application will eventually run concurrently on multiple servers, serve an API, and need to process thousands of requests per second, and I want to make sure that the design I choose now doesn't cripple any of those

Centos ifconfig显示网卡与/etc/sysconfig/network-sacripts/下显示网卡不一致问题解决

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ifconfig显示网卡与/etc/sysconfig/network-sacripts/下显示网卡不一致问题解决例如： ifconfig显示eth2,eth3,/etc/sysconfig/network-sacripts/为eth0、eth1,将eth2,eth3修改为eth0,eth1 1、查看网卡的UUID，并记录网卡UUID 查看网卡UUID命令：nmcli con 2、查看ifconfig -a 或者/etc/udev/rules.d/70-persistent-net.rules文件中的信息记录HWaddr地址 3、分别修改/etc/sysconfig/network-sacripts/中的ifcfg-eth0、ifcfg-eth1中的UUID、HWaddr为eth2、eth3的UUID、HWaddr 4、备份/etc/udev/rules.d/70-persistent-net.rules文件 5、重启服务器，重新生成70-persistent-net.rules文件来源： CSDN 作者： gangma2 链接： https://blog.csdn.net/vsxiaomage/article/details/80150732

Python multiprocessing doesn't play nicely with uuid.uuid4()

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问题 I'm trying to generate a uuid for a filename, and I'm also using the multiprocessing module. Unpleasantly, all of my uuids end up exactly the same. Here is a small example: import multiprocessing import uuid def get_uuid( a ): ## Doesn't help to cycle through a bunch. #for i in xrange(10): uuid.uuid4() ## Doesn't help to reload the module. #reload( uuid ) ## Doesn't help to load it at the last minute. ## (I simultaneously comment out the module-level import). #import uuid ## uuid1() does work

设置开机自动挂载

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继上次为重新磁盘分配空间后，过段时间开机却发现空间依然是满的，这就很让人疑惑了，之前不是设置的好好的么？ 1.发现问题 df 一下，并未发现之前设置好的 /dev/sda2和/dev/sda3 root@wzy:~# df 文件系统 1K-块已用可用已用% 挂载点 udev 736936 0 736936 0% /dev tmpfs 152212 1432 150780 1% /run /dev/sda1 10253588 9253136 459884 96% / tmpfs 761056 12 761044 1% /dev/shm tmpfs 5120 4 5116 1% /run/lock tmpfs 761056 0 761056 0% /sys/fs/cgroup /dev/loop1 3840 3840 0 100% /snap/gnome-system-monitor/100 /dev/loop2 43904 43904 0 100% /snap/gtk-common-themes/1313 /dev/loop3 15104 15104 0 100% /snap/gnome-characters/317 /dev/loop5 144128 144128 0 100% /snap/gnome-3-26-1604/92 /dev/loop4 4352 4352 0

How to use uuid with postgresql gist index type?

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问题 I can't use directly uuid with gist index CREATE INDEX idx_leaderboads_values_gist ON leaderboard_entry USING gist (id_leaderboard , value); And I got this error: ERROR: data type uuid has no default operator class for access method "gist" HINT: You must specify an operator class for the index or define a default operator class for the data type. 回答1: Postgres 10 or newer btree_gist now also covers the data type uuid , like Paul commented. (And some other data types, remarkably all enum types

搭建Websocket简易聊天室

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本文，我们通过Egret和Node.js实现一个在线聊天室的demo。主要包括：聊天，改用户名，查看其他用户在线状态的功能。大致流程为，用户访问网页，即进入聊天状态，成为新游客，通过底部的输入框，可以输入自己想说的话，点击发布，信息呈现给所有在聊天的人的页面。用户可以实时修改自己的昵称，用户离线上线都会实时广播给其他用户。体验链接 http://7hds.com:8888/ 下图为最终制作完成的聊天面板 WebSocket服务器可以用其他语言编写，本文采用的方法建立在Node.js上。在Node.js中我们使用ws第三方模块来实现服务器业务逻辑的快速搭建，还需使用uuid模块生成随机id，你需要使用npm包管理器来安装ws、uuid模块。使用以下命令： npm install ws -g npm install uuid -g 安装完成之后，使用终端工具进入服务器目录，开始编写代码： //引入ws模块 var WebSocket = require('ws'); //创建websocket服务，端口port为：**** var WebSocketServer = WebSocket.Server, wss = new WebSocketServer({port: 8180}); //引入uuid模块 var uuid = require('node-uuid'); /

Returning Hex UUID as default value for Django model charfield

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I tried to create a model with identifier generated from uuid4. But what I want instead of regular uuid, I want identifier has hex uuid format (without "-"). Here is what I tried: class Model(models.Model): identifier = models.CharField(max_length=32, primary_key=True, default=uuid.uuid4().hex, editable=False) created = models.DateTimeField(auto_now_add=True) modified = models.DateTimeField(auto_now=True) def __str__(self): return self.identifier class Meta: abstract = True instead of returning unique id every time inherited class instantiated, it returns the same id because of uuid4() . I

How do I represent a UUID in a protobuf message?

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问题 I want to attach a UUID to a field in my protobuf User message example. message User { // field containing id as UUID type required string email; optional string name; } I know that protobuf messages do not yet support the UUID type. I've read that the best approach is to have a UUID message type. So I'm guessing my User message would import my UUID message proto definition and use it as a field type like so: import "myproject/UUID.proto"; message User { required UUID id; required string