uuid

How to identify iOS device uniquely instead of using UUID and UDID [duplicate]

由 别说谁变了你拦得住时间么 提交于 2019-12-18 03:32:20
问题 This question already has answers here : Unique Identification of iOS device for iOS 7.0 and above (6 answers) Closed 3 years ago . In my iOS app, I have to restrict the user to use iOS app per device. To do this I found a solution that we can use the UUID (Universally Unique Identifier) or UDID (Unique Device Identifier) . But according to this answer I can't use UUID, because if app gets deleted or reinstalled UUID has been getting changed and I don't want this. Also Apple rejects apps if

Convert ByteArray to UUID java

由 自作多情 提交于 2019-12-18 02:40:32
问题 Question is How do I convert ByteArray to GUID. Previously I converted my guid to byte array, and after some transaction I need my guid back from byte array. How do I do that. Although irrelevant but conversion from Guid to byte[] is as below public static byte[] getByteArrayFromGuid(String str) { UUID uuid = UUID.fromString(str); ByteBuffer bb = ByteBuffer.wrap(new byte[16]); bb.putLong(uuid.getMostSignificantBits()); bb.putLong(uuid.getLeastSignificantBits()); return bb.array(); } but how

UUIDs for DynamoDB?

由 て烟熏妆下的殇ゞ 提交于 2019-12-17 22:38:01
问题 Is it possible to get DynamoDB to automatically generate unique IDs when adding new items to a table? I noticed the Java API mentions @DynamoDBAutoGeneratedKey so I'm assuming there's a way to get this working with PHP as well. If so, does the application code generate these IDs or is it done on the DynamoDB side? 回答1: Good question - while conceptually possible, this seems not currently available as a DynamoDB API level feature, insofar neither CreateTable nor PutItem refer to such a

Cassandra: Generate a unique ID?

由 天涯浪子 提交于 2019-12-17 22:24:09
问题 I'm working on a distributed data base. I'm trying to generate a unique ID that will serve as a column family primary key in cassandra. I read some articles about doing this with Java using UUID but it seems like there is a probability for collision (even if it's very low). I wonder if there is a way to generate a unique ID based on time maybe? 回答1: You can use the TimeUUID type in Cassandra, which backs a Type 1 UUID . This uses the current time and the creator's MAC address and a sequence

Can we use Guid as a Primary Key in Sqlite Database

由 被刻印的时光 ゝ 提交于 2019-12-17 22:18:37
问题 Is is possible to use GUID as primary Keys in SQLITE Database?If Possible which datatype can be used? 回答1: SQLite itself does not support GUID as internal type. Except that, it does! (sort of). Remember, in SQLite any string can be used as type name, and that includes GUID or UUID (read more about SQLite datatypes). According to those rules, GUID type has affinity NONE , which is the same as for BLOB fields. With this in mind, you can create column of GUID type, and use following rules to

Generating a Hardware-ID on Windows

由 风流意气都作罢 提交于 2019-12-17 22:16:19
问题 What is the best way to generate a unique hardware ID on Microsoft Windows with C++ that is not easily spoofable (with for example changing the MAC Address)? 回答1: Windows stores a unique Guid per machine in the registry at: HKEY_LOCAL_MACHINE\Software\Microsoft\Cryptography\MachineGuid 回答2: This used to be the CPU serial number but today there are many types of motherboards and this factor is not accurate. MAC address can be easily forged. That leaves us with the internal hard drive serial

Linux软raid

由 拥有回忆 提交于 2019-12-17 18:52:17
1 什么是RAID RAID全称是独立磁盘冗余阵列（Redundant Array of Independent Disks），基本思想是把多个磁盘组合起来，组合一个磁盘阵列组，使得性能大幅提高。 RAID分为几个不同的等级，各个不同的等级均在数据可靠性及读写性能做了不同的权衡。实际工作中根据自己的业务需求选择不同的RAID方案。 2 RAID的实现方式 外接式磁盘阵列：通过扩展卡提供适配能力 内接式RAID：主板集成RAID控制器安装OS前在BIOS里配置 软件RAID：通过OS实现 3 标准的RAID 3.1 RAID0 RAID0称为条带化存储，将数据分段存储在各个磁盘中，读写均可以并行处理，因此读写速率为单个磁盘的N倍，没有冗余功能，任何一个磁盘的损坏就会导致的数据不可用。 3.2 RAID1 RADI1是镜像存储，没有数据校验，数据被同等的写入到2个或者多个磁盘中，写入速度相对慢， 但是读取速度比较快。 3.3 RAID 4 RADI4在RAID1的基础上，N个盘用于数据存储，另外加入了1个磁盘作为校验盘。一共N+1个盘，任何一个盘坏掉也不影响数据的访问 3.4 RAID 5 RAID5在RAID4的基础上，由原来的一个盘来存储校验数据，改为每个盘都有数据和校验信息的。 4 混合RAID 4.1 RAID01 先组成RAID0,然后组成RAID1. 4.2 RAID10

Are Java random UUID's predictable?

由 南楼画角 提交于 2019-12-17 18:45:38
问题 I would like to use a cryptographically secure primary key for sensitive data in a database - this cannot be guessable/predictable and it cannot be generated by the database (I need the key before the object is persisted). I understand Java uses a type 4 UUID with a cryptographically secure random number generator, however I know the UUID isn't completely random so my question is how safe is it to assume that uuids cannot be predicted from a set of existing ones? 回答1: Well if you want to know

Performance of Random UUID generation with Java 7 or Java 6

由 痞子三分冷 提交于 2019-12-17 18:35:31
问题 I have a web based Java application that generates random UUIDs for session information. One of our testers is claiming up to 350ms to generate UUIDs based upon his own profiling, but I have not yet been able to replicate his results. He points to this article http://www.cowtowncoder.com/blog/archives/2010/10/entry_429.html to help back up his results. I wanted to see if anyone else has ran into this limitation with Java's built-in UUID generation capability in either Java 6 or Java 7

How to generate unique positive Long using UUID

由 主宰稳场 提交于 2019-12-17 18:16:30
问题 I have a requirement to generate unique Long ids for my database primary key column. I thought i can use UUID.randomUUID().getMostSignificantBits() but sometimes its generating some negative long also which is problem for me. Is it possible to generate only positive long from UUID ?There will be like billions of entries so i want that each generated key must be unique. 回答1: Take a look at http://commons.apache.org/sandbox/commons-id//index.html It has a LongGenerator that can give you exactly
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