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Re: What is this thing that is called a "Data Dictionary?"

From: "Jim Stalewski" <JStalewski(at)VisaLighting(dot)com>
To: "Richard Broersma Jr" <rabroersma(at)yahoo(dot)com>,"Jasbinder Singh Bali" <jsbali(at)gmail(dot)com>
Cc: "Novice Postgresql-list" <pgsql-novice(at)postgresql(dot)org>
Subject: Re: What is this thing that is called a "Data Dictionary?"
Date: 2007-05-02 20:52:11
Message-ID: 2EA705769274A24C9637C6686F0B53E4011967A8@OE.OG.local (view raw or flat)
Thread:
Lists: pgsql-novice
FWIW, in my (admittedly limited) experience, a Data Dictionary is a
metatdata entity or concept, generated by the RDBMS.  It's essentially a
single source describing the schema - tables, relationships, views,
types, functions, triggers, stored procedures, etc.  The equivalent in
PGSQL *is* the schema, based on looking at the structure of a DB using
PGADMINIII. 

The Data Dictionary can be stored as a separate entity within an RDBMS's
structure, or it can be stored within the schema itself, as I believe it
to be in PGSQL.  

Please correct me if I'm wrong... ;)

The DBA would more likely use the Data Dictionary as a tool to help
document the database, generate ERD's, etc. as opposed to the DBA
creating the Data Dictionary as one form of documenting the database.

I should go dig up my old dusty SQL97 manual - I think data dictionary
may be mentioned there.

-----Original Message-----
From: pgsql-novice-owner(at)postgresql(dot)org
[mailto:pgsql-novice-owner(at)postgresql(dot)org] On Behalf Of Richard Broersma
Jr
Sent: Wednesday, May 02, 2007 3:29 PM
To: Jasbinder Singh Bali
Cc: Novice Postgresql-list
Subject: Re: [NOVICE] What is this thing that is called a "Data
Dictionary?"

Thanks Jas for the description,  it is very helpful.

Regards,
Richard Broersma Jr.

--- Jasbinder Singh Bali <jsbali(at)gmail(dot)com> wrote:

> AFAIK, data dictionary is just the metadata (read only set) that 
> contains the definitions of data elements like tables, views, 
> trigggers, SPs, roles, general DB structuring, space allocation 
> methodology of the DB etc (i mean any data element inside the DB).
> 
> It can be viewed as a simple read only file defining the basic 
> structure of the database actually, in lay men terms.
> 
> Also most of the times, i've observed that its hidden from the users 
> even though its read only. Only DBA should have access to such kind of

> file in secured systems. Thats how we implement it in our projects out
here.
> 
> Bookkeeping is just synonymous to a data dictionary that would not 
> contain the actual data but would essentially explain the way data 
> would be managed and how.
> 
> I hope this helps.
> 
> Thanks,
> ~Jas
> 
> On 5/2/07, Richard Broersma Jr <rabroersma(at)yahoo(dot)com> wrote:
> >
> > Many of the ERD and SQL books that have have read refer to a data 
> > dictionary.  However, I seem to be missing the point of what it 
> > acuatally is.  IIRC, some books refer to it as a kind of document 
> > created by a DB designer, and other suggest that it is a kind of 
> > RBDMS created metadata.
> >
> > Can anyone please offer a consise description or provide a link to 
> > that describes what it is?
> > Also, how is this information useful to a DBA?
> >
> > Thanks for the help!
> >
> > Regards,
> > Richard Broersma Jr.
> >
> > ---------------------------(end of 
> > broadcast)---------------------------
> > TIP 3: Have you checked our extensive FAQ?
> >
> >                http://www.postgresql.org/docs/faq
> >
> 


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Subject: Re: What is this thing that is called a "Data Dictionary?"
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