Talk:Data dictionary

Photograph?

 * What would you photograph? The disk drive it sits on? RayGates 01:03, 23 August 2006 (UTC)
 * Hah now that's funny LOL. SqlPac 03:55, 9 June 2007 (UTC)
 * Probably referring to a dialog or table Elantrix 04:16, 13 June 2007 (UTC)

Example
Does anyone have an example of a Data Dictionary? —Preceding unsigned comment added by 205.213.72.2 (talk • contribs)

Or a template? —Preceding unsigned comment added by 233.109.211 (talk • contribs)

I have a few based off a DFD diagram, this is probably more complexity then needed, i will post then later when i get time.Elantrix 10:44, 27 August 2007 (UTC)

Datamanager was a data dictionary product independent of any DBMS. — Preceding unsigned comment added by 219.89.193.46 (talk) 02:03, 15 July 2011 (UTC)

Datamanager was a product developed by Management Systems & Programming Ltd. (MSP) of London. — Preceding unsigned comment added by 219.89.193.46 (talk) 02:09, 15 July 2011 (UTC)

DBMS Data Dictionary vs. an abstract Data Dictionary definition
The definition of a Data Dictionary in the context of a DBMS seems very similar to the one used by Oracle(r). Do other DBMSs have a similar definition of a Data Dictionary? That is, is this definition extensible to ther DBMSs?


 * specifically that section i.e. "The data Dictionary consists of record types (tables) created in the database by systems generated command files, tailored for each supported back-end DBMS. Command files contain SQL Statements for CREATE TABLE, CREATE UNIQUE INDEX, ALTER TABLE (for referential integrity), etc., using the specific statement required by that type of database." is confusing because the just stating The data dictionary does not suffice to introduce the narrow DBMS context.--Joelemaltais (talk) 10:18, 19 September 2011 (UTC)

The statement "...it may include both semantics and representational definitions for data elements" seems to me to be part of a definition of a more abstract data dictionary (than one just within a DBMS).

May be the more abstract definition a Data Dictionary would be better appearing before the more detailed definition of one within the context of a DBMS.

Martin 17:33, 28 December 2005 (UTC)

A bit of history...
The idea of databases was beginning to appear by the early 1970s. It soon became obvious that a database application would have so many components that it might be useful to have a parallel BoM (bill-of-materials) database to keep track of the real database. Thus was born the "data dictionary."

In the early days there was debate as to whether or not the dictionary should be "active" (100% in sync with the database) or "passive" (separate from the database & updated via separate (likely manual) processes. Cullinet's IDMS/IDD is an example of an "active" dictionary (IDD - integrated data dictionary) 100% tied to the DBMS.  IBM's IMS dictionary is a DBMS with a "passive" dictionary.  To use the IMS DBMS, it is not necessary to use the separate IMS data dictionary product.  An "active" dictionary would be tightly coupled to its DMBS engine.  Passive dictionaries could be more flexible in supporting the many different DBMSs & file types in use in a typical organization.

In the late 1980s, IBM's abortive AD/Cycle, RepositoryManager effort effectively changed the name of data dictionary to "metadata repository." Duly note that by the mid 2010s, "repository" is now often used to simply mean a database.

The precise meaning of "data dictionary" is difficult to pin down since it depends on how an organization chooses to use it. Some experience the dictionary as just a list of tables & data elements. A full, robust data dictionary will keep track of data elements, data structures, programs, systems & other components relevant to a portfolio of software applications.

While the original intent of data dictionaries was to document databases/files/software portfolios, they have been used for many other purposes.

As a BoM "database" the dictionary—if properly populated with accurate systems information—could easily answer "where used" & "provenance" questions.

Data dictionaries enjoyed their heyday during the reign of the central mainframe, but have largely fallen into obscurity with the rise of heavily distributed computing. DEddy (talk) 11:32, 19 September 2018 (UTC)DEddy (talk) 21:51, 19 September 2011 (UTC)