Re: What is this thing that is called a "Data Dictionary?"
От | Jim Stalewski |
---|---|
Тема | Re: What is this thing that is called a "Data Dictionary?" |
Дата | |
Msg-id | 2EA705769274A24C9637C6686F0B53E4011967A8@OE.OG.local обсуждение исходный текст |
Ответ на | Re: What is this thing that is called a "Data Dictionary?" (Richard Broersma Jr <rabroersma@yahoo.com>) |
Список | 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@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. > > > > ---------------------------(end of > > broadcast)--------------------------- > > TIP 3: Have you checked our extensive FAQ? > > > > http://www.postgresql.org/docs/faq > > > ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend This email and any files transmitted with it are confidential and intended solely for the use of the individual or entityto whom they are addressed. If you have received this email in error please notify the sender and delete it. Pleasenote that any views or opinions presented in this email are solely those of the author and do not necessarily representthose of the company. No employee or agent is authorized to conclude any binding agreement on behalf of Visa Lighting with another party by emailwithout express written confirmation by an authorized representative of the Company. Finally, the recipient should check this email and any attachments for the presence of viruses. The company accepts no liabilityfor any damage caused by any virus transmitted by this email.
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