uuid

生成UUID使用sys_guid()函数即可 select sys_guid() from dual; 但是上面获取的是RAW类型, 我们通常需要的是VARCHAR2类型的字符串 select lower(RAWTOHEX(sys_guid())) from dual; 使用这个即可获取到转为小写的并且是字符串的UUID 如果是在存储过程中应用, 可以创建一个FUNCTION来返回对应的UUID, 方便我们调用 --返回不带'-'的UUID CREATE OR REPLACE FUNCTION get_uuid RETURN VARCHAR IS guid VARCHAR(50); BEGIN guid := lower(RAWTOHEX(sys_guid())); RETURN guid; END get_uuid; --返回带'-'的UUID CREATE OR REPLACE FUNCTION get_uuid RETURN VARCHAR IS guid VARCHAR(50); BEGIN guid := lower(RAWTOHEX(sys_guid())); RETURN substr(guid, 1, 8) || '-' || substr(guid, 9, 4) || '-' || substr(guid, 13,4) || '-' || substr(guid,

I am using UUID v1 as the primary key. I would like to sort on UUID v1 timestamp. Right now if I do something like select id, title from table order by id desc Postgresql does not sort records by UUID timestamp, but by UUID string representation, which ends up with unexpected sorting result in my case. Am I missing something, or there is not a built in way to do this in Postgresql? The timestamp is one of the parts of a v1 UUID. It is stored in hex format as hundreds nanoseconds since 1582-10-15 00:00 . This function extracts the timestamp: create or replace function uuid_v1_timestamp (_uuid

I am wondering about the format UUIDs are by default represented in CouchDB. While the RFC 4122 describes UUIDs like 550e8400-e29b-11d4-a716-446655440000 , CouchDB uses continuously chars like 3069197232055d39bc5bc39348a36417 . I've searched some time in both their wiki and their documentation what this actually is, however without any result. Do you know whether this is either a non RFC-conform format omitting all - or is this a completely different representation of the 128 bits. The background is that I'm using Java UUIDs which are formatted as noted in the RFC. I see the advantage that the

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am making android BLE app. As per the Documents, I make application. My Problem is that sometime the app will work good , but sometime it throw the errors .There is 2 logs, one for success and 2nd for the errors. Every time bluetooth disconnect, i am send close method. I don't know where I am stuck. 1st success log 2nd log As in above Logs , the 1st display the data but in 2nd i got the issue of status 8 , it will happen after 3 or 4 successful connection .My thought is that, If there is issue in the code then it is not given me single

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: i am trying to convert the Column in the Dataset from varchar to UUID using the custom datatype in Spark SQL. But i see the conversion not happening. Please let me know if i am missing anything here. val secdf = sc.parallelize( Array(("85d8b889-c793-4f23-93e9-ea18db640039","Revenue"), ("85d8b889-c793-4f23-93e9-ea18db640038","Income:123213"))).toDF("id", "report") val metadataBuilder = new MetadataBuilder() metadataBuilder.putString("database.column.type", "uuid") metadataBuilder.putLong("jdbc.type", java.sql.Types.OTHER) val metadata =

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: One of the reasons, and probably the main one, to use UUID is to avoid having a "centralized" point responsible for creating and assigning ids to resources. That means that, for REST APIs, the clients could (and should) be able to generate, and give the UUID for a certain resource when they POST that specific resource for the first time. That would minimize problems related with successfully posting a resource for the first time but not getting the ID back as response (connectivity problems for example). That can result in a new

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm trying to take a uuid and convert it back into the bytes it was generated from. I've been studying the SecureRandom source to see if I can reverse engineer the UUID back into bytes, but I'm having a hard time with it. What I need to do is basically the inverse of this: def self.uuid ary = self.random_bytes(16).unpack("NnnnnN") ary[2] = (ary[2] & 0x0fff) | 0x4000 ary[3] = (ary[3] & 0x3fff) | 0x8000 "%08x-%04x-%04x-%04x-%04x%08x" % ary end So I have this uuid: "4b6d2066-78ac-49db-b8c4-9f58d8e8842f" Which started out as this string of bytes

I try to make a uuid (v 3.0.1) package work in Node/Typescript app, but I'm not sure what should I import and how to use it. This is index.d.ts (from @types/uuid v 2.0.29): declare namespace uuid { interface V1Options { node?: number[]; clockseq?: number; msecs?: number | Date; nsecs?: number; } type V4Options = { random: number[] } | { rng: () => number[]; } interface UuidStatic { (options?: V4Options): string; (options: V4Options | null, buffer: number[], offset?: number): number[]; (options: V4Options | null, buffer: Buffer, offset?: number): Buffer; v1(options?: V1Options): string; v1