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ITSS 230 - Fundamentals of Databases > Week 2 -Chapter 3 > Flashcards

Week 2 -Chapter 3 Flashcards

1
Q

Used extensively in mathematics to provide a framework in which an assertion (statement of fact) can be verified as either true or false

A

Predicate Logic

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2
Q

A part of mathematical science that deals with sets, or groups of things, and is used as the basis for data manipulation in the relational model

A

Set Theory

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3
Q

In data modeling, the construct used to organize and describe and attirbutes set of possible values

A

Attribute Domain

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4
Q

Also known as an attibute domain. It is the set of allowable values for an attribute.

A

Domain

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5
Q

In the relational model, an identifier composed of one or more attributes that uniquely identifies a row, also a candidate key selected as a unique entity identifier

A

Primary Key PK

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6
Q

One or more attributes that determine other attributes.

A

Key

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7
Q

The role of a key. In the context of a database table, the statement “A determines B” inidicates that knowing the value of attribute A means that the value of attribute B can be looked up.

A

Determination

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8
Q

Within a relation R, an attribute B is functionally dependent on an attribute A if and only if a given value of attibute A determines exactly one value of attribute B. The relationship “B is dependent on A” is equivalent to “A determines B” and is written as A -> B

A

Functional Dependence

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9
Q

Any attribute in a specific row whose value directly determines other values in that row

A

determinant

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10
Q

Any attribute whose value is determined by another attribute

A

Dependent

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11
Q

A condition in which an attribute is functionally dependent on a composite key but not on any subset of the key

A

Full functional dependence

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12
Q

A multiple attribute key

A

Composite key

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13
Q

An attribute that is part of a primary key

A

Key attribute

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14
Q

An attribute or attributes that uniquely identify each entity in a table

A

superkey

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15
Q

A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey

A

candidate key

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16
Q

The property of a relational table that guarantees each entity has a unique value in a primary key and that the key has no null values

A

Entity Integrity

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17
Q

The absence of an attribute value. Note that a ____ is not a blank

A

Null

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18
Q

A primary key from one table that is placed into another table to create a common attribute. The values in the __________ must be constrained to ensure referential integrity.

A

Foreign key FK

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19
Q

A condition by which a dependent tables foreign key entry must have either a null entry or a matching entry in the primary key of the related table.

A

referential integrity

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20
Q

A key used strictly for data retrieval purposes that does not require a functional dependency. For example, customers are not likely to know their customer number (PK), but the combination of last name, first name, mi, and telephone number will probably match the appropriate table row.

A

Secondary Key

21
Q

Special codes implemented by designers to trigger a required response, alert end users to specified conditions, or encode values. ____ may be used to prevent nulls by bringing attention to the absence of a value in a table.

A

Flags

22
Q

A set of mathematical principles that form the basis for manipulating relational table contents; the eight main functions are: SELECT, PROJECT, JOIN, INTERSECT, UNION, DIFFERENCE, PRODUCT, DIVIDE

A

RELATIONAL ALGREBRA

23
Q

Short for relation variable, a variable that holds a relation. A _____ is a container (variable) for holding relation data, not the relation itself.

A

RELVAR

24
Q

A property of relational operators that permits the use of relational algebra operators on existing tables (relations) to produce new relations

A

Closure

25
Q

A SQL command that yields the values of all rows or a subset of rows in a table. The ______ statement is used to retrieve data from tables. In relational algebra, ______ is an operator used to ____ a subset of rows. aka RESTRICT

A

SELECT

26
Q

In relational algebra an operator used to select a subset of columns.

A

PROJECT

27
Q

In relational algebra, an operator used to merge (append) two tables into a new table, dropping the duplicate rows. The tables must be union-compatible.

A

UNION

28
Q

Two or more tables that have the same number of colums and the corresponding columns have compatible domains.

A

Union-Compatible

29
Q

In relational algebra, an operator used to yield only the rows that are common to two union compatible tables.

A

INTERSECT

30
Q

In relational algebra, an operator used to yield all rows from one table that are not found in another union-compatible table.

A

DIFFERENCE

31
Q

In relational algebra, an operator used to yield all possible pairs of rows from two tables

A

PRODUCT

32
Q

In relational algebra, a type of operator used to yield rows from two tables based on criteria. There are many types of ____ natural, theta equi___, and outer

A

JOIN

33
Q

A relational operation that yields a new table composed of only the rows with common values in their common attributes.

A

natural join

34
Q

Columns that are used in the criteria of join operations. The ________ generally share similar values

A

join columns

35
Q

A join operator that links tables based on an equality condition that compares specified columns of the tables

A

equijoin

36
Q

A join operator that links tables using an inequality comparison operator (<. >, <=, >=) in the join condition.

A

theta join

37
Q

A join operation in which only rows that meet a given criterion are selected. The criterion can be an equality condition (natural join or equijoin) or an inequality condition (theta join). The most commonly used type of join.

A

Inner Join

38
Q

A join operation that produces a table in which all unmatched pairs are retained; unmatched values in the table are left null.

A

Outer Join

39
Q

A join operation that yields all the rows in the left table, including those that have no matching values in the other table.

A

left outer join

40
Q

A join operation that yields all of the rows in the right table, including the ones with no matching values in the other table.

A

right outer join

41
Q

In relational algebra, an operator that answers queries about one set of data being associated with all values of data in another set of data.

A

DIVIDE

42
Q

A detailed system data dictionary that describes all objects in a database

A

System Catalog

43
Q

The use of the same name to label different attributes. Should generally be avoided.

A

Homonyms

44
Q

The use of different names to identify the same object, such as an entity, an attribute, or a relationship; should generally be avoided

A

Synonyms.

45
Q

An entity designed to transform an M:N relationship into two 1:M relationships. The composite entity’s primary key comprises at least the primary keys of the entities that it connects.

A

Composite entity, associative entity, bridge entity

46
Q

In the relational model, a table that implements an M:N relationship

A

Linking table

47
Q

An ordered array of index key values and row ID values (pointers). ______ are generally used to speed up and facilitate data retrieval

A

Index, Index Key

48
Q

An index in which the index key can have only one associated pointer value (row)

A

Unique index

ITSS 230 - Fundamentals of Databases (3 decks)

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