Re: Define "flatten database" ?
From: Tom Hester <thester_at_metadata.com>
Date: Fri, 28 Jan 2005 10:18:36 -0800
Message-ID: <35535$41fa8120$45033832$31722_at_msgid.meganewsservers.com>
>
>
> I would guess "normalize" is more likely. If the source dbms permits
> non-1NF structures, then the term "flatten" is sometimes used to mean that
> the data are put in1NF. Terms I might use as synonyms to "flatten" are
> "unnest", "explode", "normalize". It isn't quite the same as normalizing,
> however, because the embedded lists are not placed in a separate relation,
> but rather the "scalar" data are repeated in each row, while the list has
> one value per row. Reasons to flatten the structure would include a need to
> use a SQL-92-based tool or pour the data into a single Excel worksheet.
>
> If the source dbms is a SQL-based product, then the user might still be
> dumping tag-delimited lists in as attribute values (we all know there are
> people who do that, right?) or even using some non-1NF capabilities of the
> particular RDBMS.
>
> Example:
>
> Start with:
>
> (12345,DeSmith,John,{jsmith_at_aol.com,JohnSmith_at_yahoo.com})
> (23127,Meador,Beth,{beth_meador_at_msn.com,bmeador_at_hotmail.com,btm_at_ibm.org})
>
> Then flatten it to get:
>
> (12345,DeSmith,John,jsmith_at_aol.com)
> (12345,DeSmith,John,JohnSmith_at_yahoo.com)
> (23127,Meador,Beth,beth_meador_at_msn.com)
> (23127,Meador,Beth,bmeador_at_hotmail.com)
> (23127,Meador,Beth,btm_at_ibm.org)
>
> That's my best guess. --dawn
>
>
>
>
>
Received on Fri Jan 28 2005 - 19:18:36 CET
Date: Fri, 28 Jan 2005 10:18:36 -0800
Message-ID: <35535$41fa8120$45033832$31722_at_msgid.meganewsservers.com>
People that I know that use it mean denormalize.
Dawn M. Wolthuis wrote:
> "DA Morgan" <damorgan_at_x.washington.edu> wrote in message
> news:1106859773.807419_at_yasure...
>
>>silversw2000_at_yahoo.com wrote: >> >> >>>I had a database analyst interview yesterday on the phone, and the >>>interviewer brought up the phrase: "I flattened the database". >>> >>>I did not obfuscate in replying to her thread, but was able to avoid >>>having to know what she meant by that term. >>> >>>Can someone define "flatten database" for me, in 100 words or less (OK >>>500 words is fine). >>> >>>Fred Z. >>> >> >>Denormalize.
>
>
> I would guess "normalize" is more likely. If the source dbms permits
> non-1NF structures, then the term "flatten" is sometimes used to mean that
> the data are put in1NF. Terms I might use as synonyms to "flatten" are
> "unnest", "explode", "normalize". It isn't quite the same as normalizing,
> however, because the embedded lists are not placed in a separate relation,
> but rather the "scalar" data are repeated in each row, while the list has
> one value per row. Reasons to flatten the structure would include a need to
> use a SQL-92-based tool or pour the data into a single Excel worksheet.
>
> If the source dbms is a SQL-based product, then the user might still be
> dumping tag-delimited lists in as attribute values (we all know there are
> people who do that, right?) or even using some non-1NF capabilities of the
> particular RDBMS.
>
> Example:
>
> Start with:
>
> (12345,DeSmith,John,{jsmith_at_aol.com,JohnSmith_at_yahoo.com})
> (23127,Meador,Beth,{beth_meador_at_msn.com,bmeador_at_hotmail.com,btm_at_ibm.org})
>
> Then flatten it to get:
>
> (12345,DeSmith,John,jsmith_at_aol.com)
> (12345,DeSmith,John,JohnSmith_at_yahoo.com)
> (23127,Meador,Beth,beth_meador_at_msn.com)
> (23127,Meador,Beth,bmeador_at_hotmail.com)
> (23127,Meador,Beth,btm_at_ibm.org)
>
> That's my best guess. --dawn
>
>
>>-- >>Daniel A. Morgan >>University of Washington >>damorgan_at_x.washington.edu >>(replace 'x' with 'u' to respond)
>
>
>
Received on Fri Jan 28 2005 - 19:18:36 CET