Database Relations Properties Quiz
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Database Relations Properties Quiz

Test your knowledge on the properties of relations in databases, including attributes, tuples, table structure, and more. Explore the distinct characteristics that define a well-structured database relation.

Created by
@DesirableToad

Questions and Answers

Match the following terms with their definitions:

Tuple = A record in a table Attribute = A column within a table File = A collection of records Field = A cell in a table

Match the following relational key concepts with their descriptions:

Superkey = Identifies a record uniquely within a table Candidate Key = Minimal superkey for a relation Primary Key = Selected to identify records uniquely within a table Foreign Key = Matches candidate key of another table

Match the following integrity concepts with their definitions:

Relational Integrity = Rules that define or constrain some aspect of the organization. Entity Integrity = In a base table, no column of a primary key can be null. Referential Integrity = If FK exists in a table, either FK value must match a candidate key value of some record in its home table. Business Rules = Rules that define or constrain some aspect of the organization.

Match the following statements with the correct representation:

<p>Each cell of a table contains exactly one atomic value. = Properties of Relations Order of columns has no significance. = Properties of Relations Represents value for a column that is currently unknown or not applicable for record. = Relational Integrity Two main languages: SQL (Structured Query Language), standardized by ISO. = Relational Languages</p> Signup and view all the answers

Match the following relational model components with their descriptions:

<p>Structural part = Part of the relational model that defines the tables and their columns Manipulative part = Part of the relational model that involves operations like insert, update, delete Integrity rules = Set of rules ensuring data consistency and accuracy in the relational model RM Terminology = Collection of terms used to describe the elements and operations in the relational model</p> Signup and view all the answers

Match the following relational integrity terms with their meanings:

<p>Null = Represents the absence of a value and is not the same as zero or spaces Foreign Key = Column within one table that matches candidate key of another table Alternate Keys = Candidate keys that are not selected to be primary key Primary Key = Candidate key selected to identify records uniquely within a table</p> Signup and view all the answers

Match the following database terms with their definitions:

<p>Relation = Table with columns and rows Attribute = Named column of a relation Domain = Set of allowable values for one or more attributes Tuple = A record of a relation</p> Signup and view all the answers

Match the following properties of relations with their characteristics:

<p>Each record is distinct; there are no duplicate records. = Properties of Relations Table name is distinct from all other table names in the database. = Properties of Relations Values of a column are all from the same domain. = Properties of Relations Each column has a distinct name. = Properties of Relations</p> Signup and view all the answers

Each cell in a table can contain multiple values.

<p>False</p> Signup and view all the answers

Primary Key is selected from Alternate Keys in a relation.

<p>False</p> Signup and view all the answers

Order of columns has significance in a relation.

<p>False</p> Signup and view all the answers

Null represents a value that is the same as zero or spaces.

<p>False</p> Signup and view all the answers

SQL and QBE are two main relational languages used to query databases.

<p>True</p> Signup and view all the answers

Entity Integrity states that in a base table, every column of a primary key can be null.

<p>False</p> Signup and view all the answers

Relational Integrity Business Rules are rules that define or constrain some aspect of the organization.

<p>True</p> Signup and view all the answers

Referential Integrity ensures that a Foreign Key (FK) must always match a Primary Key (PK) value in another table.

<p>True</p> Signup and view all the answers

A Tuple in the relational data model refers to a column of a relation.

<p>False</p> Signup and view all the answers

The Relational Database is a collection of denormalized relations with similar relation names.

<p>False</p> Signup and view all the answers

Study Notes

Alternative Terminology

  • Relation, attribute, tuple are equivalent to table, column, record
  • File, field, row are alternative terms
  • Combinations of these terms are used in different contexts

Properties of Relations

  • Table name is distinct from all other table names in the database
  • Each cell of table contains exactly one atomic (single) value
  • Each column has a distinct name
  • Values of a column are all from the same domain
  • Each record is distinct; there are no duplicate records
  • Order of columns has no significance
  • Order of records has no significance, theoretically

Relational Keys

  • Superkey: a column, or a set of columns, that uniquely identifies a record within a table
  • Candidate Key: a minimal superkey for a relation
  • Primary Key: a candidate key selected to identify records uniquely within a table
  • Alternate Keys: candidate keys that are not selected to be primary key
  • Foreign Key: a column, or set of columns, within one table that matches candidate key of some (possibly same) table

Relational Integrity

  • Null: represents a value for a column that is currently unknown or not applicable for a record
  • Deals with incomplete or exceptional data
  • Represents the absence of a value and is not the same as zero or spaces, which are values
  • Entity Integrity: in a base table, no column of a primary key can be null
  • Referential Integrity: if foreign key (FK) exists in a table, either FK value must match a candidate key value of some record in its home table

Relational Languages

  • Two main languages: SQL (Structured Query Language), standardized by ISO
  • QBE (Query-by-Example), an alternative graphical “point-and-click” way of querying a database

Relational Model

  • Describes the world as “a collection of relations (or tables)”
  • Data Model: an integrated collection of concepts for describing data, relationships between data, and constraints on the data
  • Has three components: a structural part; a manipulative part; a set of integrity rules

RM Terminology

  • Relation: table with columns and rows
  • Attribute: named column of a relation
  • Domain: set of allowable values for one or more attributes
  • Tuple: a record of a relation
  • Relational Database: a collection of normalized relations with distinct relation names

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