Definitions

Underlined  terms apply to CIS 231. Terms appearing in red apply to the first CIS231 test. Bolded black terms apply to CIS 220 and subsequent courses. These definitions are placed here for the student's convenience for study outside the classroom. They are not characterized as all inclusive. Definitions may vary slightly between textbooks. Definitions listed here are acceptable to Mr. Stout's classes and his testing requirements. 

Page and figure references used refer to your CIS 220 textbook by Peter Rob and Elie Semaan.

1st NF  - a table is in first normal form if it does not contain repeating groups

2nd NF - a table is in second normal form if it is in first normal form and no nonkey attribute is dependent on only a portion of the primary key

3rd NF - a table is in third normal form if it is in second normal form and it contains no transitive dependencies

4th NF – a table is in fourth normal form if it is in 3rd NF and there are no multivalued dependencies

Ad hoc query – a query constructed by the user for one time execution

Append – to add or attach to the end

Append query – a query to attach or append data to an existing table

Atomic Key – an attribute that cannot be subdivided into meaningful lower components       

Attribute – also a field or column, the cumulative attributes identify a record. A characteristic of an entity.

BCNF – Boyce-Codd Normal Form, a special case of the 3rd Normal form.  A table is BCNF if it is in 3rd NF and there are not transitive dependencies and if the only determinant it contains is a candidate key. See transitive dependency, first, second and third normal form definitions to fully understand BCNF. 

Bit – a binary unit, 1 or 0, or at the lowest level a + or – mili-volt storing a data unit  

Bound text box - a text box linked to a field in a database table

Boyce-Codd NF - also BCNF, a table is in 3rd NF and there are no transitive dependencies    

Bridge table - a database table that is designed to connect or link two or more related tables. Such a table uses at least the primary key components of the tables to be linked. Also called a composite table.

Business rules – short and concise statements that establish the existence and composition of entities, attributes, relationship and constraints of a set of database relationships, defined by how an enterprise really works

Byte – 8 bits, or one character from a character set   

Case tool - computer assisted engineering, a class of software developed to assist in database and other software development, Oracle Designer and Visio are examples of case tools.

Calculated field – a field containing an expression to derives a value from other data sources or fields   

Candidate key – a potential primary key or a super key without redundancies but that is not selected to be the PK.

Cardinality   - defines the relationship between entities, 1:1, 1:M, M:M. The minimum and maximum values for the entity occurrences that occur in a related table.

Character - an alpha or numeric figure, in Oracle “Char” is a data type meaning text  

Chen methodology - an ER modeling annotation methodology similar to Crow's Foot, IDEFIX and Rein85. See Figure 1.28 and Figure P1.9 on pages 43-50.

Column – also a field or attribute, a unit of data in a record 

Compound Primary Key – a primary key composed of more than one field or column  

Composite attribute - an attribute that can be divided into meaningful components

Composite primary key - a primary key that is based on a combination of attributes

Computed field – a derived field, the named result of an expression

Concatenate – laid end to end such as the column of a compound primary key     

Context – data becomes information when give context and format, data viewed in relation to its environment

Convention – a set of rules      

Criteria – a set of criterion for selecting a subset of data

Criterion – a descriptive bases for selecting a subset of data

Data – text and values in the raw form, unprocessed

Data anomaly - any data that fails to conform to the general rules. Example: color entered as size

Data dictionary – contains metadata, data about data, fully describes all data in a table

Data integrity – reliable, uncorrupted data  

Data type - a characteristics that determines which field values can be used. Examples: text, value or number, ole, etc. The allowable data types is determined by the DBMS vender.

Database – data stored in structure with policies and procedures that enforce data integrity, a database ceases to exist as a database with it loses structure and data integrity

DB2 – an IBM DBMS

DBA – database administrator

DBMS – database management system such as Access and Oracle for creating, managing, maintaining and processing data into information

DDL – data definition language

Determinant – an attribute that determines another column is called a determinant  

Dependency - a condition that is established when the value of an attribute is dependent on the value of another attribute.

DML – data management language, a subset of SQL statements

Duplicate – repeated data

Entity – a table or relation containing a data set  

Entity integrity - a condition in which each relational database table row is uniquely identified through a primary key.

Entity set – a set of related records contained in a table

E-R model – a data model describing and configuring a database, includes relationships and data dictionary

ERD – entity relation diagram which uses symbols to indicate entity sets, relationships and relationship types to produce an easily read, easily organized and easily expanded database blueprint.

Expression – a formula or set of descriptive logic  

Existence dependent - a condition that exists when one entity cannot exist without the related entity's presence. Example: the entity dependent is DEPENDENT on the entity EMPLOYEE existing.

File – a named object stored on a medium, the pathname includes the filename, location and other descriptive parameters

Filter – a method of eliminating unwanted data, cannot be saved in Access as an object

Flat file – a self-contained table without relations

Foreign key – the primary key when repeated in a related table, an attribute in one table whose values must either match the primary key in another table or be null

Format – how data is formed for human application and use, a component of data processing

Functional dependency – a column (attribute) is functionally dependent on another column if a value in the second column determines a single value for the first at any one time

Hierarchical database - a database design concept designed along lines of major components composed of a hierarchy of subcomponents, developed to support the Saturn rocket program

HTML – hypertext markup language, the language of the Internet

Hyperlink – a method for linking objects and files using HTML

Indexing – functions similar to a card catalog that makes it possible to arrange records in a different order using a much smaller data set

Information – processed data

Inner Join – an SQL query operation that results in only those records for which the linking entity is found in all joined tables

Integer – a whole number, not a fraction or decimal

Intersect – a join that produces a listing that contains only the rows that appear in both tables

Join – a query that combines data from 2 or more tables or tables and queries

Logical operators – a set of symbols representing logical operations such as =, <>, >, <, >=, <=, ?, !, like, and, or,  not, between

Macro – in Access it is method for writing quick VBA programs to accomplish database manipulations

Macro-view – a larger view or generalized view

Mandatory – required for the function to work

Mathematical operators -  symbol indicating mathematical operations, in Access: + - / * and ^  

Metadata - data about data, the contents of the data dictionary

Maximum cardinality - the maximum units that can exist in the relationship consistent with the business rules.

Micro – a limited or highly detailed view of a data or functional set

Minimal Super Key - (see super key)

Minimum cardinality - the minimum units that can exist within the relationship without violating the business rules

Multivalued attribute - an attribute that can have many values, example: an instructor can have many degrees, therefore, attribute degree can many values. 

Naming convention – an agreed set of rules or guidelines for naming an object

Natural join – links tables by selecting only the rows with common values in their common attributes

Network Database – an obsolete database concept similar to hierarchical containing multiple flat files

Nonkey attribute – an attribute is a nonkey attribute if it is not a part of a primary key

Normal Form – a label that is used to indicate the nature of the dependencies that exist between the attributes within an entity.

Normalization – a process that changes table structures to increase their normal form rating. Higher normal forms are required to minimize data redundancy. This process is most easily accomplished with the help of dependency diagrams.

Null – non-data, the absence of data

Number – a numerical character, could be text unless defined as a value

Object – an identifiable construction

OLE – object linking and embedding, digit data usually photographic or graphic. A protocol by which an object, such as a photograph, a spreadsheet, video, sound, etc., can be inserted into and used by an application.

Optional or optionality - having the quality of not required but possibly existing as regards the cardinality of a relationship between entities

Oracle 8i –Oracle Corporation DBMS product

Outer Join – an outer join is a structured query language (SQL) operation that preserves unmatched rows from one or more joined tables.

Parameter – a value that determines the outcome of a query, the parameter places a constraint on the output of the query

Pathname – a text string that names and describes a file and its stored location

Primary key – a field, column or attribute that uniquely defines a record

Product join – a join that lists all possible pairs of rows from two tables

Property – a quality that defines how an object looks and behaves

Protocol – a set of rules

QBE – query by example

Query – a join, a utility for selecting and manipulating one or more data sets

Record – a row or tuple in a table, relation or entity

Redundancy – repeated data most often unnecessarily

Relation – table or entity meaning a set of records

Relational algebra – a process of defining and building joins

Relationship – a table or tuple containing a data set

Reliability – a standard of expectations

Root – the base

Row – record or attribute

Schema – a diagram of relations similar to but less complete than an E-R model

Secondary key – an attribute or key used purely for data retrieval purposes

Select query – a query that selects a set of records from one or more tables based on some criteria

Set – a collection of records composing a table with like fields and formats

SQL (structured query language) – a set of 23 programming statements designed to create, edit and manipulate a database

SQL Server – a Microsoft DBMS similar to Access for large enterprises

Sub type – see super type, mechanics represent sub type in the relationship

Super key – an attribute that uniquely identifies each entity in a table

Super type – a 1:1 relationship in which one table contains all records in set and in which the related table contains only a subset or subtype. Example: Employees table (super type) contains all employees but mechanics table (sub type) holds only those employees who are mechanics

Switchboard – set of menus for users

Table – relation or entity meaning a set of records

Transitive dependency – exists only when a nonkey attribute determines another nonkey attribute. Example: Postal code and city when used an attributes but not as primary keys.

Trigger – a set of stimuli that cause a designed response in a database system. The stimuli may be an input in the client that “triggers” a change in the client that can be seen or evidenced in the client

Tuple – a record or row, an archaic name used in many textbooks for record

Union – combines all rows from two or more tables

Value – a numerical property relative to zero plus or minus

View – an image of database

Weak entity – an existence dependent entity, entity "dependents" is dependent on entity "employee" to exit.

Wizard – an application function that assists the user by offering questions with options or choices

Naming conventions:

Table: must concisely describe the data contained in the record set. Example: tblStudents where the table contains all students without further parametric qualification

Query: must describe how data is processed and cannot be the same name as a table. Example: qryMaleDayStudents where the data source contains all students but the criteria of the query results in only male day students who are male.

Fields: identify the table source of its determinant key with underscores to connect name components. Examples: stu_LNAME for last name found in tblStudent

Prefix: table = table, qry = query, form =  form and rpt = report