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)