Structured Query Language (SQL)

the most popular query language used for interacting with a database. It allows people to perform complicated searches by using relatively simple statements or key words.

"SELECT"

typical key word to choose a desired attribute

"FROM"

Typical key word to specify the table or tables to be used

"WHERE"

Typical key word to specify conditions to apply in the query.

query by example (QBE)

Another way to find information in a database is to use _____________________________ in which the user fills out a grid or template to construct a sample of a description of the data desired.

form

a grid or template

Entity Relationship diagram

document that shows data entities and attributes and relationships among them

business rules

precise descriptions of policies, procedures, or principles in any organization that stores and uses data to generate information

data dictionary

The ______________________ provides information on each attribute such as its name, if it is a key, part of a key, or a non-key attribute, the type of data expected, and valid values.

relationships

illustrate an association between entities

degree of a relationship

the _________________________ indicates the number of entities associated with a relationship

unary relationship

a _____________________________ exists when an association is maintained within a single entity

binary relationship

exists when two entities are associated

ternary relationship

exists when three entities are associated

connectivity

describes the relationship classification

cardinality

refers to the maximum number of times an instance of one entity can be associated with an instance in the related entity

cardinality

can be mandatory single, optional single, mandatory many, or optional many

1. mandatory single
2. optional single
3. mandatory many
4. optional many

what are the 4 possible cardinality symbols?

one-to-one

in a __________________________, a single-entity instance of one type is related to a single-entity instance of another type

Normalization

A method for analyzing and reducing a relational database to its most streamlined form for minimum redundancy, maximum data integrity, and best processing performance.

Functional Dependencies

means of expressing that the value of one particular attribute is associated with a specific single value of another attribute

join operation

combines records from two or more tables in a database to obtain information that is located in different tables