RE: true definition of a transaction

I would not say that the definition of a transaction varies with the technology, but with the application. Take the classic bank transfer transaction. In this case we're decrementing a savings account by x and incrementing the checking account by the same value. Depending on your point of view either part of the affair can be called a transaction or the whole is a transaction. It really depends on what your idea of the basic unit of work is. Traditionally a transaction is ended by a commit, but that's not always true.=20

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From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Leslie Tierstein Sent: Tuesday, May 03, 2005 5:15 PM
To: ryan_gaffuri_at_comcast.net; oracle-l_at_freelists.org Subject: RE: true definition of a transaction

In a data warehouse, "transaction" is typically used to indicate the lowest level of granularity of a base fact table. For example, I'm in the process of writing a paper in which I included a sentence like:

The main fact table, for Point of Sale (POS) data, is aggregated to the level of Item-Store-Date - we do not receive individual = transactions.=3D20

So, a transaction could be in a 1:1 correspondence with a row of a fact table maintained at the txn level of granularity -- which would be the case if our DW contained actual POS data. The row in the DW started life as an OLTP transaction, although, as you state, the DW DB did not actually issue any corresponding commits.

=3D20

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From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of ryan_gaffuri_at_comcast.net
Sent: Tuesday, May 03, 2005 4:39 PM
To: oracle-l_at_freelists.org
Subject: true definition of a transaction

Does the definition of a transaction vary depending on technology? The high level definition is basically a 'single unit of work'. However, in oracle a transaction is a commit, in J2EE EJB world a transaction can include an in memory change to a variable, in sql server, i think selects are included in the definition of a transaction.=3D20 I heard a guy on the radio who claims to run a company that 'implemented one the highest transaction data warehouses in the world'. To me that is an oxymoron. By definition data warehouses are read mostly, with period data loads.=3D20

has anyone else noticed this? any comments?=3D20

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http://www.freelists.org/webpage/oracle-l Received on Tue May 03 2005 - 17:26:23 CDT