Database System

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.

note!Answer: C) Procedural query Language
Relational algebra is a procedural query language because it specifies the operations and their order to obtain results.

note!Answer: C) Foreign Key
A foreign key is an attribute in one table that references the primary key of another table, linking them.

note!Answer: D) both (A) and (B)
A DBMS provides data independence and centralized control of data, which are key advantages of database systems.

note!Answer: C) (A) and (B) both are true
In a relational model, rows have no inherent order and every row must be distinct, so both statements are true.

note!Answer: D) independent of both hardware and software.
The conceptual model describes data and relationships at a logical level, independent of any hardware or software.

note!Answer: B) Binary
A relationship between two entities is called a binary relationship. Unary involves one entity, and ternary involves three.

note!Answer: A) PROJECTION
The projection operation selects specific columns from a table. Selection picks rows instead.

note!Answer: D) All of the above
CHARACTER, NUMERIC and FLOAT are all standard SQL data types.