Database Quiz 2

Relational Database Model

represents information by storing data in tables which are related together using keys

Data Table

stores information about a thing

Data Subset Table

stores additional information for a thing that is stored in a Data Table

Linking Table

used to implement a many to many relationship between two tables

Validation Table

defines the valid values that may be used in a column of another table

Functional Dependency

a relationship where the value of an attribute (or set of attributes) uniquely determines the values of another attribute (or set of attributes)

Determinant

a Functional Dependency is an attribute whose value uniquely determines the value of another attribute (the Dependent)

Dependent

of a Functional Dependency is the attribute whose value is determined by another

attribute’s value

Augmentation

a functional dependency remains true when the same attribute is added as both a determinant and a dependent

Transitivity

a rule stating that if A determines B, and B determines C, then A must also determine C

Decomposition

provides that if ”A” determines “B” and “C”, then it is also true that “A” determines “B” by itself and “A” determines “C” by itself

Composition

provides that if “A” determines “B” by itself is true and “A” determines “C” by itself is true, then ”A” determines both “B” and “C” together is also true.

Multivalued Dependency

when one attribute can determine multiple values for another attribute

Full Functional Dependency

when you need the whole determinant, not just part of it, to determine the dependent

Trivial Functional Dependency

where the all dependent attributes are also determinant attributes.

Superkey

a set of one or more attributes that can uniquely identify each row in a table

Candidate Key

a minimal set of attributes that can uniquely identify each row in a table

Primary Key

the specific column (or set of columns) in a table that is chosen to uniquely identify

each row

Alternative Key

a Candidate Key which was not picked to be the Primary Key

Non-Key Field

any column in a database table that is not part of a key used to uniquely identify rows

Foreign Key

a column restricts its values to only those values which exist in the column that the Foreign Key refers to

Composite

when two or more columns combined function as a single unit

Surrogate Key (Artificial Key)

a unique identifier that has no real world meaning and is used solely to identify a row in a table

Auto-Incrementing

automatically assigns the next sequential number to a column whenever a new row

is inserted

Referential Integrity Constraint

a rule that ensures that a foreign key value in one table always corresponds to an existing primary key value in another table

Data Integrity

the Validity, Consistency and Accuracy of data

Validity

means that data follows the correct format is an allowed value

Consistency

means that data does not contradict other data

Accuracy

means that data is correct

Tuple

more formal term for a row in a database tabl

Multipart Field

a single column that combines multiple distinct pieces of information as a single value.

Duplicate Fields (Repeating Groups)

multiple columns that store non-distinct pieces of information

Multivalued Field

a single column that stores multiple non-distinct pieces of information

Calculated Field

column whose value is derived from the value of other columns

Anomaly

a data inconsistency, invalidity, or error that occurs when you insert, update, or deletedata in a table

Normalization

a process of restructuring a database table to minimize data redundancy and improve data integrity

Relation

a more formal term of a database table that meets conditions required to start the normalization process

Normal Form

set of specific rules that a table must satisfy as a stage in the normalization process