問題描述
Стварэнне парадкавага нумара ў mongoDB (Generating sequence number in mongoDB)
I am using java,Datanucleus,mongodb and JDO in my project.
I have a requirement where I should generate sequence number and store it in DB. I was going through various links and found that DataNucleus supports the automatic assignment of sequence values for object identities only for the following datastore:‑
Oracle
PostgreSQL
SAP DB
DB2
Firebird
HSQLDB
H2
Derby (from v10.6)
DB4O
So does that mean ‑> sequence generation can't be done for mongoDB? If it can be then please provide some useful link or guidance !
Note:I am already aware of the fact that mongoDB creates an object id on its own..but I want custom sequence number generation,store it in DB and use it.
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參考解法
方法 1:
DataNucleus‑MongoDB supports "INCREMENT" value strategy, as stated very clearly in the docs, and additionally supports many other strategies.
(by Abhinav、DataNucleus)