Re: [libreoffice-users] definition of flat/relational database

Hi John,

John R. Sowden schrieb:
> Why do the Libreoffice powers that be define dbase/xbase as  a flat file
> database, not a relational database.  The below definitions from the
> Base Intro documentation demonstrate what I am saying:

Do you have a direct link?

> *Flat databases*
>
> A flat database contains one or more tables, each containing one or more
> fields. Each table is completely independent of all the other tables in
> the database. For example, I have an address database with seven tables
> in it. One has my family's contacts, another has my business contacts,
> and another has my wife's family contacts. While some contacts are
> contained in more than one table, different tables may not have the same
> information about the same person.
>
> dBase is a flat database program. LibreOffice and several database
> programs can also create flat databases.
>
> *Relational databases*
>
> Relational databases contain one or more tables with one or more
> relationships; each relaltionship is defined by a pair of fields. One
> field of each pair belongs to one table and the second field belongs to
> the same or a different table. Where relationships exist between fields
> in the same or different tables, a flat database could still be used,
> but it provides no mechanism for defining the relationship. Instead the
> same data must be entered in both fields, making data entry errors more
> likely. A well designed relational database requires the data to be
> entered only once, reducing possible errors.

I think, it is a wrong definition of the term 'relational database'. The 
word 'relation' in 'relational database' means the mathematical 
definition of 'relation', which is connected to 'tupel', a organization 
of data in rows and columns. It is not about a 'relationship'.

Another database model is a hierarchical model for example, which is 
tree-like.

http://en.wikipedia.org/wiki/Relational_database.
http://en.wikipedia.org/wiki/Database_model
http://de.wikipedia.org/wiki/Datenbankmodell

It seems, that 'Flat database' is used for a database with one single 
table. But such a database would still be a relational database. My 
German text book does not have any term which would correspond to 'Flat 
database'. And the German Wikipedia article has no database model 'Flat 
database'.

> dbase is a relational database per the above definition.  I link 2
> tables with 1 field so I can refer to data in the second database so
> data does not have to bbe entered multiple times.  In our alarm
> monitoring station, when a police dept. changes its phone number, we
> change 1 field in 1 database.  Hundreds of subscriber records refer to
> that field to populate the data screen.  It seems that LO ptb either
> have a problem with dbase/xbase, or they are (were) uninformed of the
> facts.

dBase is a relational database application because the data is organized 
in tables.

I think, there is no need to introduce the term 'flat database' at all. 
The distinction is in the management system. For files in dBase-format 
and for spreadsheets, LibreOffice itself is the database management 
system. For all other database connections, it uses an external database 
management system.

Kind regards
Regina


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