uuid | 易学教程

How to insert a specific UUID in h2 database?

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问题 I need to insert some default data in my database. I am using Spring Boot with the Flyway integration. For testing, I use H2. For production MySQL will be used. I have made separate Flyway migration scripts so I can use database specific stuff for the default data (Creating the tables is done in a common script). For MySQL, I have something like this: INSERT INTO survey_definition (id, name, period) VALUES (0x2D1EBC5B7D2741979CF0E84451C5BBB1, 'disease-activity', 'P1M'); How can I do the same

Android. How do I set UUID Beacon value to proper textview?

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问题 This is a silly question, but I have a code which is giving me list of beacons with their names, addresses, uuids, majors and minors in TextView. I'm calculating uuid, major and minor values(in code below). And when I'm setting these three values into TextView they are swaping with other beacon values. So my question is, how do I set proper uuid, major and minor value to the proper beacon? Link with the example: http://i.stack.imgur.com/vlepI.jpg I have got two beacons. Names and adresses are

android 蓝牙socket（spp）用法

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1 综述蓝牙socket连接必须实现服务器端和客户端的机制。一个设备必须打开一个Server Socket，而另一个必须发起连接（使用服务器端设备的MAC地址发起连接）。当服务器端和客户端在同一个RFCOMM信道上都有一个BluetoothSocket时，则两端就建立了连接。此刻，每个设备都能获得一个输入输出流，进行数据传输。下面分别介绍服务器端和客户端的实现。 2 服务器端服务器端有两个线程，一个是accept线程负责监听来自client的连接请求，一个是connected线程负责与client 进行数据传输。 accept线程首先创建一个server socket, 通过调用listenUsingRfcommWithServiceRecord(String, UUID)方法得到一个BluetoothServerSocket对象。[注: 用此方法listenUsingRfcommWithServiceRecord(String, UUID)创建的socket,需要双方进行配对确认，之后双方在一个加密且鉴权过的通信信道上通信。而用listenUsingInsecureRfcommWithServiceRecord（String, UUID）创建的socket不需要双方进行配对确认，通信信道上没有鉴权过的link key,容易受到MITM（Man-in-the-Middle

How to get UUID generated by MySQL into a C# variable

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问题 Here is the query: string query = @"INSERT INTO session (PK_Id, user_id, login_time, machine_ip, machine_fingerprint) VALUES (UUID(), @UId, @LogInTime, @MIp, @MFingerPrint); "; Now I need this last inserted id back, which is a UUID generated by MySQL. As far as I read there is no select_last_insert_id() function for UUIDs!! And I read for php you could assign UUID() function first to a variable and then return that value. But how to go about that in C#? Something like this, but not exactly:

Symfony2 & FOSRestBundle: Getting UUID packed in a BINARY(16) field from MySQL

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问题 I am facing a weird problem relating to UUIDs. I have developed a REST API using Symfony2+FOSRestBundle+JMSSerializer. As I need to update some tables from two sources I thought of using UUID as primary key for one entity. I did a doctrine:mapping:import to generate entities in my Symfony project. Everything correct. I ended up with the following entity (only exposing the key field and generated getter for simplicity): <?php namespace Stardigita\TgaAPIBundle\Entity; use Doctrine\ORM\Mapping

generate UUID automatically for all records in Cassandra for an existing dataset

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问题 I have an existing dataset with around 700000 records in a CSV format. I have imported that data file into apache Cassandra table. The problem is primary key. How can I automatically generate (upsert) uuid into my primary key column for all of my records? I am using Cassandra 3.10. 回答1: Unfortunately, if you're using the COPY command you don't really have any options for generating UUIDs on the fly for your rows. I think you really have two options, both of which involve doing things

How unique and random are javascript generated uuids?

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问题 I'm considering generating unique identifiers for data in javascript using one of the uuid methods discussed here. Most likely something along the lines of this one since it uses window.crypto if it's available. These id's don't need to be globally unique, only unique per user. Will this generate sufficiently unique ids for a large scale application? Is there any reason to think this will result in id collisions? Can javascript generate a sufficiently random uuid for this to work? It looks

Problem with UUID and GUID

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问题 Please don't mark this as duplicate. I have gone through all posts on this topic but couldn't solve my problem. I have an application in J2ME that searches for bluetooth services with a particular UUID: UUID[] uuidSet = { new UID("100000",true) }; int[] attrSet = {0x0100, 0x0003, 0x0004}; int transID = agent.searchServices(attrSet,uuidSet,remoteDevice,this); I have a desktop application in VB.NET using 32feet.NET library that creates a new bluetooth service with a particular GUID. Sub

What does “clock sequence” mean?

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问题 RFC 4122 ( A Universally Unique IDentifier (UUID) URN Namespace ) uses the term "clock sequence": 4.1.5. Clock Sequence For UUID version 1, the clock sequence is used to help avoid duplicates that could arise when the clock is set backwards in time or if the node ID changes. If the clock is set backwards, or might have been set backwards (e.g., while the system was powered off), and the UUID generator can not be sure that no UUIDs were generated with timestamps larger than the value to which

Unique serial number in a java web application

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问题 I've been wondering what's the correct practice for generating unique ids? The thing is in my web app I'll have a plugin system, when a user registers a plugin I want to generate a unique serial ID for it. I've been thinking about storing all numbers in a DB or a file on the server, generating a random number and checking whether it already exists in the DB/file, but that doesn't seem that good. Are there other ways to do it? Would using the UUID be the preferred way to go? 回答1: If the ids