Here is an example of how to create and use Oracle Change tables. This is part of what Oracle refers to as “change data capture” or CDC.

Oracle change tables allow you to capture what has changed in a specific table over a period of time. This can be useful if you are attempting to keep data updated with a source. Typically CDC is used as part of the “extract” process in an extract-transform-load procedure for loading a data warehouse.

There are many sties and articles on this topic that go into much more depth than I will here, however I have never found a fully functional demonstration of an entire CDC cycle.

Change table example code

For more information on change data capture I recommend Oracle’s Data Warehousing Guide. More on data warehousing in general can be found at Mark Rittman’s Oracle Weblog.

A new feature in Oracle 10g called ‘streams’ offers an alternative to this type of CDC, however I (and I’m sure many others) are still dealing with change tables on a regular basis.

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