1 1 vote Spot the wrong statement. Subschema is related with external view only. Data dictionary is a tool used exclusively by the database administrator. To define a schema DDL, DML and DCL are comulsory. SET concept is used in network model Unknown Category databases + – sh!va 1.2k views answer comment Share Follow Print 0 reply Please log in or register to add a comment.
1 1 vote I think C) is incorrect . A). External level deals only that portion which is concerned to the user or application programmer which is also known as external schema or subschema . TRUE B). A set of information describing the contents, format, and structure of a database and the relationship between its elements, used to control access to and manipulation of the database.Hence, to manipulate and control the database , which database admin only has rights to do uses data dictionary to ease the access . TRUE https://en.wikipedia.org/wiki/Data_dictionary C). DDL statements are used to alter/modify a database or table structure and schema. http://www.tech-recipes.com/rx/55356/dml-ddl-dcl-and-tcl-statements-in-sql-with-examples/ D). Set concept is used in network database model.TRUE http://people.cs.pitt.edu/~chang/156/18network.html Kapil answered Jul 17, 2016 Kapil comment Share Follow See all 2 Comments 2 2 Comments reply sh!va commented Jul 17, 2016 reply Follow flag Can you please tell what are all compulsory to define a schema? 0 0 replyShare Kapil commented Jul 17, 2016 i edited by Kapil Jul 17, 2016 reply Follow flag schema uses all .. but DCL is not compulsory.. 1 1 replyShare Please log in or register to add a comment.
