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MIS 302-Final

Terms

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Star schema
data modeling technique used to map multidimensional decision support data into a relational database
Dimensions
qualifying characteristics that provide additional perspectives to a given fact
Attribute hierarchy
provides a top-down data organization that is used for two main purposes—aggregation and drill-down/roll-up data analysis
Full functional dependence
if the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that composite key (p66)
Derived attribute
an attribute who's value is calculated from other attribute; does not need to be physically stored in a database, it can be derived using an algorithm (p108)
Data store
a DSS database containing business data and business model data
Business rule
brief, precise, unambiguous description of a policy, procedure, or principle within a specific organization (p31)
Fact tables
contain facts that are linked through their dimensions
Data mining
process of analyzing data to uncover problems or opportunities hidden in the data and relationships, also form computer models based on their findings, and then use the models to predict business behavior
Primary key (PK)
an identifier composed of one or more attributes that uniquely identifies any given row (p64)
Information
the result of processing raw data to reveal its meaning (p6)
Ad hoc query
spur of the moment question, or request for data manipulation (p7)
Data models
relatively simple representations, usually graphical, of more complex real-world data structures (p29)
INTERSECT
statement used to combine rows from two queries, returning rows that appear in both sets
Metadata
data about data (p6)
MINUS
statement that combines rows from two queries and returns only the rows that appear in the first set but not in the second
First Normal Form (1NF)
level of normalization where all key attributes are defined and when all remaining attributes are dependent on the primary key; still contains partial and transitive dependencies
Completeness constraint
specifies whether each entity supertype occurrence must also be a member of at least one subtype; can be partial or total (p189)
Recursive query
a nested query that joins a table to itself; when employees manage other employees
Functional dependence
if each value in column A determines one and only one value in column B; attribute A determines attribute b if all of the rows in the table that agree in value for attribute A also agree in value for attribute B (p65)
Composite attribute
an attribute that can be further subdivided to yield additional attributes (p105)
End-user query tool
used by DA to create the queries that access the database
Data anomaly
when all of the required changes in redundant data are not made successfully (ex. Update anomalies, Insertion anomalies, and Deletion anomalies) (p17)
Total completeness
means that every supertype occurrence must be a member of at least one subtype (p189)
Dimension tables
places where dimensions are stored
Cardinality
expresses the minimum and maximum of entity occurrences associated with one occurrence of the related entity; a teacher can teach 0 to 5 classes (0, 5) (p109)
Statement-level trigger
trigger executed once, before or after the triggering statement is completed
Referential integrity
if the foreign key contains a value, the value refers to an existing valid row in another relation (p68)
Foreign key (FK)
an attribute whose values match the primary key values in the related table (p68)
UNION
statement that combines rows from two or more queries without including the duplicate rows
Data mart
small, single-subject data warehouse subset that provides decision support to a small group of people
Data redundancy
when the same data are stored unnecessarily at different places (p16)
Second Normal Form (2NF)
level of normalization where it is 1NF and contains no partial dependencies
Partial completeness
means that not every supertype occurrence is a member of a subtype; there may be some supertype occurrences that are not members of any subtype (p189)
Multi-valued attribute
can have many values; a car's color can be subdivided into many colors (roof body, and trim color) (p106)
Data warehouse
integrated, subject-oriented, time-variant, nonvolatile collection of data that provides support for decision making
Characteristics of a relational table
consists of intersecting rows and columns that represents a single value, each row is a single entity occurrence, a column represents an attribute and each one has a distinct name, all data in a column must be in the same format, order of rows and columns is immaterial to the DBMS, each table must have a key (p62)
Normalization
a process for evaluating and correcting table structures to minimize data redundancies, thereby reducing the likelihood of data anomalies
Data
raw facts that have not been processed to reveal their meaning (p5)
Data extraction/ filtering
component used to extract and validate data taken from the operational database and external data sources
Third Normal Form (3NF)
level of normalization where it is 2NF and contains no transitive dependencies
Transitive dependency
dependency of one nonprime attribute on another nonprime attribute
End-user presentation tool
used by the DA to organize and present the data
Inheritance
the ability of an object within the class hierarchy to inherit the attributes and methods of the classes above it (p42)
Overlapping subtypes
subtypes that contain non unique subsets of the supertype entity set; each entity instance of the supertype may appear in more than one subtype (p187)
Connectivity
term used to label the types of relationships (ex. 1:M, 1:1, M:N) (p39)
Correlated subquery
subquery that executes once for each row in the outer query
Facts
numeric measurements that represent a specific business aspect or activity
Inner join
a join operation in which only rows that meet a given criteria are selected (natural join)
Cross join
forms a relational product (or Cartesian product) of two tables
Composite key
a key that is composed of more than one attribute (p65)
Composite/ Bridge entity
table used to link the tables that originally were related in a M:N relationship (p84)
Persistent stored module (PSM)
block of code that is stored and executed at the DBMS server
Decision support system (DSS)
an arrangement of computerized tools used to assist managerial decision making within a business
Row-level trigger
trigger executed once for each row affected by the triggering statement
Procedural SQL (PS/SQL)
a language that makes it possible to use and store procedural code and SQL statements within the database
Outer join
a relational-algebra JOIN operation that produces a table in which all unmatched pairs are retained; unmatched values are left null (left and right join)
Determinant
any attribute in a specific row whose value directly determines other values in that row
Non-overlapping subtypes
subtypes that contain a unique subset of the supertype entity set; each entity instance of the supertype can appear in only one of the subtypes (p187)
Trigger
procedural SLA code that is automatically invoked by the RDBMS upon the occurrence of a given data manipulation event
Partial dependency
a dependency based on only part of a composite primary key
UNION ALL
statement used to produce a relation that retains duplicate rows
Index selectivity
a measure of how likely an index will be used in query processing
Subtype discriminator
the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related (p187)

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