The mechanism how the database concurrency works

Could some body explain me how the database concurrency works? I am using HSQLDB.

For example, if there are two different users to insert a record at the same time from two different entry points, how does the database handle this? Are these开发者_如何学运维 two insert commands executed one by one? or at the same time?

Feel free to provide any other information if you know.

Many thanks!

Ike

Most databases worth knowing can handle requests from multiple sources. Each request is handled in turn as it comes in. The question is: how are they interleaved? This is where isolation and locking come into play. I'd recommend that you read up on ACID properties for relational databases. There's a lot of information available, both for relational and NoSQL databases.