Computer & IT

note!Answer: B) Hashed File
Hashing applies a hash function to the key to compute the record's address. This is the defining feature of a hashed file.

note!Answer: A) Parent-Child relationship between the tables that connect them.
A primary key referenced by a foreign key forms a parent-child (one-to-many) relationship between the two tables.

note!Answer: B) Dashed ellipse
In E-R diagrams, derived attributes are drawn as dashed ellipses, while regular attributes are solid ellipses.

note!Answer: C) Binary Operator
The cross product (Cartesian product) combines two relations, so it is a binary operator.

note!Answer: A) mn
The maximum join size occurs when every tuple of R matches every tuple of S, giving m × n tuples.

note!Answer: C) Combination of selection and Cartesian product
A natural join is a Cartesian product followed by a selection on equal common attributes, and then removing duplicate columns by projection.

note!Answer: D) View never contains derived columns.
Views can contain derived columns, such as computed expressions or aggregates. The other three statements are true.

note!Answer: A) Parent-Child relationship between the tables that connect them.
A primary key referenced by a foreign key creates a parent-child relationship between the tables.

note!Answer: D) Diamond
In E-R diagrams, relationship types are drawn as diamonds, entities as rectangles, and attributes as ellipses.

note!Answer: A) Tree structure
The hierarchical model organizes data in a tree structure, with parent-child nodes.

note!Answer: C) ALTER
ALTER TABLE with DROP COLUMN removes a column from a table's structure. DROP removes the whole table, and DELETE removes rows.

note!Answer: C) IN
The IN operator checks whether a value matches any value in a specified list of literals. BETWEEN checks a range.

note!Answer: A) m
By definition, a B-tree of order m has at most m children per node. Each node can therefore hold at most m-1 keys.

note!Answer: B) MOD
MOD returns the remainder after dividing one number by another. For example, MOD(10,3) returns 1.

note!Answer: C) JOIN
JOIN combines records from two or more tables based on a related column. SELECT, PROJECT and PRODUCT do not combine records in this way.

note!Answer: D) Triangle
In an E-R diagram, generalization (and specialization) is shown as a triangle connecting the superclass to its subclasses. Entities are rectangles and attributes are ellipses.

note!Answer: A) View
A view is a virtual table defined by a SELECT query. It stores no data of its own and shows the result of that query.

note!Answer: B) Self Join
A self join joins a table to itself, usually using table aliases. It is used to compare rows within the same table.

note!Answer: A) RAW
In Oracle, the RAW data type stores binary or unstructured data. CHAR, NUMERIC and VARCHAR store character or numeric data.

note!Answer: A) Electronic Data Processing
EDP stands for Electronic Data Processing, the processing of data by electronic computers.