Computer & IT

note!Answer: D) Tree.
The hierarchical model organizes records in a tree structure with parent-child relationships.

note!Answer: C) ellipse.
In E-R diagrams, entities are rectangles, and attributes are ellipses.

note!Answer: A) not Null
Entity integrity requires that the primary key cannot be NULL.

note!Answer: A) DML
DML is the language application programs use to request and manipulate data from the DBMS.

note!Answer: B) is a standard way of organizing information into accessible parts.
A logical schema is the logical organization of data; the physical schema describes storage on disk.

note!Answer: B) data record.
Related fields make up a record, and related records make up a file.

note!Answer: B) separate files.
A database environment replaces separate files with one integrated database, so separate files are not a component.

note!Answer: B) SQL.
SQL (Structured Query Language) is the standard language for interacting with relational databases.

note!Answer: A) rectangle.
In E-R diagrams, entities are drawn as rectangles, attributes as ellipses, and relationships as diamonds.

note!Answer: B) print files on paper.
A report generator formats data from files into printed reports.

note!Answer: D) All of the above.
All three statements describe key properties of a database: integration, consolidation, and data independence.

note!Answer: C) a tuple.
In relational terminology, a row is called a tuple, a table is a relation, and a column is an attribute.

note!Answer: C) sequential.
Sequential file organization stores records physically in order of a key field.

note!Answer: A) values.
COUNT returns the number of values in a column, including duplicates unless DISTINCT is specified.

note!Answer: C) data is integrated and can be accessed by multiple programs.
A key advantage of DBMS is integrated data that many programs can share, which reduces redundancy and program dependence.

note!Answer: B) hash.
Hashing applies a key transformation (hash function) to compute the storage address of a record.

note!Answer: D) both (B) and (C).
Data independence means programs are insulated from changes in data storage (physical) and data structure (logical).

note!Answer: A) Alter.
ALTER TABLE modifies the structure of an existing table, while UPDATE changes data values.

note!Answer: C) Doubly outlined rectangle
In E-R diagrams, a weak entity set is drawn as a double-outlined rectangle; a diamond represents a relationship.

note!Answer: A) Network Model
The network data model uses the SET construct to represent owner-member relationships.