Re: What is this thing that is called a "Data Dictionary?" - Mailing list pgsql-novice

I think you're right.

I also think that the equivalent in PGSQL may be the information_schema.
That's what MySQL is trumpeting that they've added to their structure
that is the same thing as a data dictionary.

It makes sense - information_schema is a standard SQL thing, that was
introduced back with SQL92.  Oracle uses information_schema too but has
their own set of "data dictionary" views that apparently are more
comprehensive ways to access the database's metadata.

Looking at PGSQL's information_schema schema, it does have a lot of that
kind of thing.

I wonder if pg_catalog and pg_toast also are part of the PGSQL "data
dictionary" implementation...

________________________________

From: Jasbinder Singh Bali [mailto:jsbali@gmail.com]
Sent: Wednesday, May 02, 2007 4:00 PM
To: Jim Stalewski
Cc: Richard Broersma Jr; Novice Postgresql-list
Subject: Re: [NOVICE] What is this thing that is called a "Data
Dictionary?"


I think data dictionary is automatically build by the DB.
Don't think that its a manual task.
Meta data is always build up automatically by the system intelligently.
Correct me if I'm wrong.

~Jas


On 5/2/07, Jim Stalewski < JStalewski@visalighting.com> wrote:

        I just went to wikipedia.  That's what they say - a data
dictionary is
        metadata, and they say that within a DBMS it's represented as a
set of
        read-only tables and views.
        http://en.wikipedia.org/wiki/Data_dictionary

        They seem to indicate it's something that you build, though, not
        something generated by the RDBMS.

        Innnteresting...

        -----Original Message-----
        From: pgsql-novice-owner@postgresql.org
        [mailto:pgsql-novice-owner@postgresql.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@gmail.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@yahoo.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.
        > >
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        > > broadcast)---------------------------
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        > >
        > >                 http://www.postgresql.org/docs/faq
<http://www.postgresql.org/docs/faq >
        > >
        >


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