uuid

According to the documentation, hibernate 3.6 should have support for the java.util.UUID type. But when I map it like: @Id protected UUID uuid; I get the following exception: Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [test-applicationContext.xml]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: persistenceUnit] Unable to build EntityManagerFactory at org.springframework.beans.factory.support

I wonder if Oracle's SYS_GUID() function returns a RFC 4122 compliant UUID . For example: SQL> select sys_guid() from dual; SYS_GUID() -------------------------------- A6C1BD5167C366C6E04400144FD25BA0 I know, that SYS_GUID() returns a 16 byte RAW datatype. Oracle uses RAWTOHEX() and probably TO_CHAR() to print out the above ID. Is it correct to interpret this as a UUID compliant string format like: A6C1BD51-67C3-66C6-E044-00144FD25BA0 I think it's not compliant to the RFC 4122 standard, because the definition says, that a valid UUID must name the UUID-Version within the UUID itself. Syntax for

Is it possible to use UUID values as a primary key in SQLite? I'm finding extremely limited information on the topic, so I'm not sure if SQLite even supports a UUID data type. Should I be storing a UUID as a string? SQLite allows to use any data type as primary key. UUIDs can be stored either as strings (which are human-readable) or as 16-byte BLOBs (which might be faster if the records are so small that the difference matters). CL's answer is correct but kind of skirts the issue at hand. As mentioned, a column (or multiple columns) of any type can be used as a primary key. So you could store

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. Take a look at http://commons.apache.org/sandbox/commons-id//index.html It has a LongGenerator that can give you exactly what you need. In addition if you are using Hibernate then you can ask it to generate IDs for you (it has

I'm creating a rails 3 application that will be decentralized and I need to use UUID as primary key for my tables, what would be the best gem, plugin for the Job. I also would like to know if it is possible to make in ActiveRecord polymorphic relationships without using the polymorphicable_type column for it, given the case that I'm using UUID. I have created a demo http://github.com/boriscy/uuidrails3 that uses UUID as keys, you should check the module UUIDHelper inside lib/ and also all the migrations. There is no need to add a primary key in the database, just an index, because primary keys

I was browing Stack and the internet for a simple solution to get the UUID of the device I'm currently using. I stumbled over posts like this but none of them seemed to help me. The doc tells me about this getUuids() function but when going through the doc for Android Bluetooth I end up having a BluetoothAdapter but I need a BluetoothDevice to execute this function. So I need to know the following: 1) Is the function returning really the device UUID ? Because the name saids plural (getUuid s ) 2) How do I get an instance of this BluetoothDevice ? Thanks! Using reflection you can invoke the

I have some UUIDs that are being generated in my program at random, but I want to be able to extract the timestamp of the generated UUID for testing purposes. I noticed that using the fields accessor I can get the various parts of the timestamp but I have no idea on how to combine them. Looking inside /usr/lib/python2.6/uuid.py you'll see def uuid1(node=None, clock_seq=None): ... nanoseconds = int(time.time() * 1e9) # 0x01b21dd213814000 is the number of 100-ns intervals between the # UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00. timestamp = int(nanoseconds/100) +