Posts tagged lock
How Oracle Database uses internal locks to make statement level constraint validation robust at the transaction level0
Data Constraints are essential in protecting the integrity of the data in any relational database. The Oracle Database provides four types of declarative constraints that help implement various types of data rules. These are: Primary Key, Unique Key, Foreign Key and Check Constraint. Although these constraints can be configured to be enforced at transaction time (when the transaction is committed) by setting them to be deferred, the default behavior of the constraints is to enforce the integrity rule at statement level. That means that when a transaction performs multiple DML statements, the constraints are validated during execution of the statement. When the statement is done, the integrity is ensured (otherwise the statement would have failed) and additional statements can be executed.
In the multi session environment that is the Oracle Database, you could be wondering – as was I – how the Oracle Database ensures that other sessions executing DML operations can not undermine the integrity of the data touched by the current transaction. And how it can do so without needlessly preventing other sessions to perform data manipulation using various forms of locking.
It turns out that More >
I have just completed my first ever presentation on the Expertezed.com network – http://www.expertezed.com/ , a reprise from my session on Oracle OpenWorld 2012. This presentation includes a number of slides regarding 12c features, based on the session and slides from Tom Kyte (Top 12 new features) and my notes from the excellent session CON8511 – Temporal Database Capabilities with the Latest Generation of Database Technology that I attended during the conference.
You can download the slides from this presentation here:Expertezed_OOW2012_TheVeryVeryLatestInDatabaseDevelopment.pptx .