MIS 380 Database Management

Unary relationship

A relationship between instances of a single entity type.

Binary relationship

A relationship between the instances of two entity types.

Constraint

A rule that cannot be violated by database users.

Star schema

A simple database design in which dimensional data are separated from fact or event data. A dimensional model is another name for a star schema.

Ternary relationship

A simultaneous relationship among the instances of three entity types.

Entity instance

A single occurrence of an entity type.

Database management system (DBMS)

A software system that is used to create, maintain, and provide controlled access to user databases

Business rule

A statement that defines or constrains some aspect of the business. It is intended to assert business structure or to control or influence the behavior of the business

Function

A stored subroutine that returns one value and has only input parameters.

Data warehouse:

A subject-oriented, integrated, time-variant, non-updateable collection of data used in support of management decision-making processes.

Informational system

A system designed to support decision making based on historical point-in-time and prediction data for complex queries or data-mining applications.

Operational system

A system that is used to run a business in real time, based on current data. Also called a system of record.

Extensible Markup Language (XML)

A text-based scripting language used to describe data structures hierarchically, using HTML-like tags.

Reconciled data

Detailed, current data intended to be the single, authoritative source for all decision support applications.

Data model

Graphical systems used to capture the nature and relationships among data

Embedded SQL

Hard-coded SQL statements included in a program written in another language, such as C or Java.

Correlated subquery

In SQL, a sub-query in which processing the inner query depends on data from the outer query.

Conformed dimension

One or more dimension tables associated with two or more fact tables for which the dimension tables have the same business meaning and primary key with each fact table.

Application program interface (API)

Sets of routines that an application program uses to direct the performance of procedures by the computer's operating system.

Degree

The number of entity types that participate in a relationship.

Application partitioning

The process of assigning portions of application code to client or server partitions after it is written to achieve better performance and interoperability (ability of a component to function on different platforms)

Identifying relationship

The relationship between a weak entity type and its owner.

Logical schema

The representation of a database for a particular data management technology.

Systems development life cycle (SDLC)

The traditional methodology used to develop, maintain, and replace information systems.

Attribute

A property or characteristic of an entity or relationship type that is of interest to the organization.

Derived attribute

An attribute whose values can be calculated from related attribute values.

Strong entity type

An entity that exists independently of other entity types.

Associative entity

An entity type that associates the instances of one or more entity types and contains attributes that are peculiar to the relationship between those entity instances.

Weak entity type

An entity type whose existence depends on some other entity

Snowflake schema

An expanded version of a star schema in which dimension tables are normalized into several related tables.

Data warehouse

An integrated decision support database whose content is derived from the various operational databases

Prototyping

An iterative process of systems development in which requirements are converted to a working system that is continually revised through close work between analysts and users.

Database

An organized collection of logically related data.

Transient data

Data in which changes to existing records are written over previous records, thus destroying the previous data content.

Periodic data

Data that are never physically altered or deleted once they have been added to the store.

Metadata

Data that describe the properties or characteristics of end-user data and the context of those data.

Information

Data that has been processed in such a way as to increase the knowledge of the person who uses the data.

Derived data

Data that have been selected, formatted, and aggregated for end user decision support application.

Trigger

A named set of SQL statements that are considered (triggered) when a data modification (i.e., INSERT, UPDATE, DELETE) occurs or if certain data definitions are encountered. If a condition stated within a trigger is met, then a prescribed action is taken.

Entity

A person, a place, an object, an event, or a concept in the user environment about which the organization wishes to maintain data

User view

A logical description of some portion of the database that is required by a user to perform some task

Project

A planned undertaking of related activities to reach an objective that has a beginning and an end

Entity-relationship model (E-R model)

A logical representation of the data for an organization or for a business area, using entities for categories of data and relationships for associations between entities

Relationship type

A meaningful association between (or among) entity types.

Java servlet

A Java program that is stored on the server and contains the business and database logic for a Java-based application.

Repository

A centralized knowledge base of all data definitions, data relationships, screen and report formats, and other system components

Fat client

A client PC that is responsible for processing presentation logic, extensive application and business rules logic, and many DBMS functions

Three-tier architecture

A client/server configuration that includes three layers: a client layer and two server layers. Although the nature of the server layers differs, a common configuration contains an application server and a database server.

Entity type

A collection of entities that share common properties or characteristics.

Procedure

A collection of procedural and SQL statements that are assigned a unique name within the schema and stored in the database.

Database server

A computer that is responsible for database storage, access, and processing in a client/server environment. Some people also use this term to describe a two-tier client/server application.

Relational database

A database that represents data as a collection of tables in which all data relationships are represented by common values in related tables.

Conceptual schema

A detailed, technology-independent specification of the overall structure of organizational data.

Entity-relationship diagram (E-R diagram, or ERD)

A graphical representation of an entity-relationship model.

Outer join

A join in which rows that do not have matching values in common columns are nevertheless included in the result table.

Equi-join

A join in which the joining condition is based on equality between values in the common columns. Common columns appear (redundantly) in the result table.

Natural join

A join that is the same as an equi-join except that one of the duplicate columns is eliminated in the result table.

Term

A word or phrase that has a specific meaning for the business

Database application

An application program (or set of related programs) that is used to perform a series of database activities (create, read, update, and delete) on behalf of database users

Open database connectivity (ODBC)

An application programming interface that provides a common language for application programs to access and process SQL databases independent of the particular DBMS that is accessed.

Thin client

An application where the client (PC) accessing the application primarily provides the user interfaces and some application processing, usually with no or limited local data storage.

Relationship instance

An association between (or among) entity instances where each relationship instance associates exactly one entity instance from each participating entity type.

Fact

An association between two or more terms.

Identifier

An attribute (or combination of attributes) whose value distinguishes instances of an entity type

Simple (or atomic) attribute

An attribute that cannot be broken down into smaller components that are meaningful to the organization.

Composite attribute

An attribute that has meaningful component parts (attributes).

Optional attribute

An attribute that may not have a value for every entity (or relationship) instance with which it is associated.

Multivalued attribute

An attribute that may take on more than one value for a given entity (or relationship) instance.

Required attribute

An attribute that must have a value for every entity (or relationship) instance with which it is associated.

Middleware

Software that allows an application to interoperate with other software without requiring the user to understand and code the low-level operations necessary to achieve interoperability.

Dynamic SQL

Specific SQL code generated on the fly while an application is processing.

Physical schema

Specifications for how data from a logical schema are stored in a computer's secondary memory by a database management system

Data

Stored representations of objects and events that have meaning and importance in the user's environment.

Identifying owner

The entity type on which the weak entity type depends

Enterprise data modeling

The first step in database development, in which the scope and general contents of organizational databases are specified

Grain

The level of detail in a fact table, determined by the intersection of all the components of the primary key, including all foreign keys and any other primary key elements.