Advantage of PERIOD FOR clause in 12c

Question

Hello,
I'm trying to understand the new PERIOD FOR clause in 12c. After reading several examples and documentation however I'm still not sure about its advantage. What can PERIOD FOR do that I cannot achieve with using a WHERE clause on normal start and end time columns?
Thanks!

Answer 1

I'm trying to understand the new PERIOD FOR clause in 12c. After reading several examples and documentation however I'm still not sure about its advantage. What can PERIOD FOR do that I cannot achieve with using a WHERE clause on normal start and end time columns?
It can do a whole lot more than what you can achieve yourself. If it couldn't Oracle wouldn't have invested so much time and money in it. (I'm pretty sure they knew the WHERE clause solution was already available )
What 'several examples and documentation' are you talking about? Post links to EXACTLY what you read.
The Oracle documentation discusses the topic pretty thoroughly.
Did you read ALL of Chapter 5, Managing and Maintaining Time-Based Information, in the VLDB and Partitioning Guide?
http://docs.oracle.com/cd/E16655_01/server.121/e17613/part_lifecycle.htm
That chapter is extensive and has some examples of using ILM and even Heat Map and ADO to implement ILM.
Did you read the 'Temporal Validity Support' section in the Database Development guide?
http://docs.oracle.com/cd/E16655_01/appdev.121/e17620/adfns_design.htm#CACHEBFC
Temporal Validity Support lets you associate one or more valid time dimensions with a table and have data be visible depending on its time-based validity, as determined by the start and end dates or time stamps of the period for which a given record is considered valid. Examples of time-based validity are the hire and termination dates of an employee in a Human Resources application, the effective date of coverage for an insurance policy, and the effective date of a change of address for a customer or client.
Temporal Validity Support is typically used with Oracle Flashback Technology (described in Chapter 16), for queries that specify the valid time period in AS OF and VERSIONS BETWEEN clauses. You can also use the DBMS_FLASHBACK_ARCHIVE.ENABLE_AT_VALID_TIME procedure (described in Oracle Database PL/SQL Packages and Types Reference) to specify an option for the visibility of table data: all table data (the default), data valid at a specified time, or currently valid data within the valid time period at the session level.
Temporal Validity Support is useful in Information Lifecycle Management (ILM) and any other application where it is important to know when certain data becomes valid (from the application's perspective) and when it becomes invalid (if ever).