The Use of a Data Dictionary

Week Four Individual Assignment
DBM502 Database Management
14 May 2012
prof Saqib Jamshed

The use of a entropy mental lexicon
A info dictionary is basically a list used to catalogue everything in databases, such as the number of records, the names, and type of each playing field contained within them. According to the oracle documents site, there be three primary uses of a data dictionary:
* To find cultivation about users, schema objects, and storage structures.
* To modify the data dictionary every time a data definition wrangle (DDL) is issued.
* As a read-only reference for reading about the database that is come-at-able to users.

Data dictionaries hold the definitions of the data coifs, tables, and data elements within the database(s), also information about storage locations, user access and privileges, and occurrences (how often the data is accessed) whether it is hourly, daily, or weekly (HNComputing, 2007a). Each of these three levels is defined by a set of attributes, the core set of which corresponds to ISO 11179 standard for describing data elements (Data dictionary -, 2012). Because the entire attribute set is flexible, they plunder be added/removed from/to the system respectively.



(Data dictionary -, 2012)
in that respect are two classes of data elements in a data dictionary: Non-common elements are unique and are only in one database table exclusively, whereas common elements are universal; they are things like State/Country codes that may be in more than one table.
The information a database dictionary is the set of tables that provide all the information about the database(s), such as:
* The definitions of all schema objects in the database (tables, views, indexes, clusters, synonyms, sequences, procedures, functions, packages, triggers, and so forth)
* How much quadruplet has been allocated for, and is currently used by, the schema objects
* Default values for columns
* one constraint information...If you want to get a full essay, invest it on our website: Orderessay



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