Glossary

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Glossary

aggregate function	(SQL) Function that operates on a group of rows, for example, SUM.	sql/functions.php
aggregation	(UML) An association in which one class represents an assembly of components from one or more other class types. Components may also exist without being part of the assembly.	aggregate.php
alias	(SQL) An alternate, short name for a table in the FROM clause of a SELECT statement.	jointypes.php
ALTER TABLE	(SQL) Statement to change structure, constraints, or other properties of a table.	tables.php
AS	(SQL) Keyword to specify a column alias in the SELECT clause.	sql/functions.php
assignment rule	(RM) The association of each attribute in a scheme with its domain.	class.php
association	(UML) The way that two classes are functionally connected to each other.	association.php
association class	(UML) A class that contains attributes which are the properties of an association rather than a regular class.	manymany.php
association, many-to-many	See many-to-many association.	manymany.php
association, one-to-many	See one-to-many association.	association.php
association, recursive	See recursive association.	recursive.php
attribute	(UML,ER,RM) One piece of information that characterizes each member of a class.	class.php
attribute, derived	See derived attribute.	manymany.php
attribute, descriptive	See descriptive attribute.	class.php
attribute, discriminator	See discriminator attribute.	loan.php
attribute, multivalued	See multivalued attribute.	hobbies.php
attribute, repeated	See repeated attribute.	phone.php
base table	(SQL) A table that is referenced by a view definition.	sql/views.php
BCNF	(RM) Boyce-Codd normal form: a database with no subkey in any relation (with no exceptions).	subkeys.php
candidate key (CK)	(RM) A minimal super key, candidate to become primary key.	keys.php
cardinality	(ER) See multiplicity.	association.php
Cartesian product	(RA) The result of the join of two relations with no join attributes specified, as defined in set theory. See also cross join.	sql/join.php
check constraint	A Boolean condition that the database applies to a row whenever that row is updated or inserted.	constraints/check_constraints.php
child	(RM,TM) The relation on the "many" (FK) side of a one-to-many association.	association.php
class	(UML) Any "thing" in the enterprise that is to be represented in the database.	class.php
column	(TM) See attribute.	tables.php
COMMIT	(SQL) Statement to make changes to data permanent.	sql/ddldml.php
compatible	(RA) Two schemes are compatible if their intersection is null or if the intersection attributes inherit the same assignment rule from their respective schemes.	sql/join.php
complete specialization	(UML) All members of a superclass must also be members of at least one subclass.	subclass.php
composition	(UML) Stronger form of aggregation in which components cannot exist without being part of the assembly.	aggregate.php
constraint	(RM,TM) Any restriction on the values that can be entered in a table.	tables.php
CREATE TABLE	(SQL) Statement to do just what the name implies.	class.php
cross join	(SQL) Paste of every pair of tuples from each relation, disregarding join attributes. See also Cartesian product.	jointypes.php
data definition language (DDL)	(SQL) Statements to create and modify tables and other database objects.	sql/ddldml.php
data dictionary	(SQL) System tables that hold information about the structure of the database.	sql/ddldml.php
data integrity	(TM) In part, the value entered in each field of a table is consistent with its attribute domain.	domains.php
data manipulation language (DML)	(SQL) Statements to work with data in a table.	sql/ddldml.php
data types	(SQL) As in programming languages, the data type that an attribute can hold in a table. This is not the same as the domain of an attribute.	sql/ddldml.php
DELETE	(SQL) Statement to remove some or all rows from a table.	sql/ddldml.php
denormalization	(RM) Intentionally "breaking the rules" of normal forms.	normalize.php
derived attribute	(UML) An attribute that can be computed from data stored elsewhere in the database.	manymany.php
descriptive attribute	(UML) An attribute that provides real-world information, relevant to the enterprise, about the class that we are modeling.	class.php
design pattern	(UML) Modeling situations that you will encounter frequently in database design.	manymany.php
discriminator attribute	(RM,TM) An attribute that allows us to discriminate between multiple pairings of the same two individuals from each side of a many-to-many association.	loan.php
disjoint specialization	(UML) Each member of a superclass may be a member of no more than one subclass	subclass.php
DISTINCT	(SQL) Optional clause of the SELECT statement. Use when the SELECT attributes do not form a super key of the FROM clause.	sql/multijoin.php
domain	(RM) The set of legal values that may be assigned to an attribute.	class.php
domain, enumerated	See enumerated domain.	enum.php
DROP CONSTRAINT	(SQL) Optional clause of the ALTER TABLE statement.	sql/ddldml.php
DROP TABLE	(SQL) Statement to delete a table and all of its contents.	sql/ddldml.php
entity	(ER) See class.	class.php
entity-relationship (ER) model	An enterprise modeling tool used in database design.	models.html
enumerated domain	(RM) A domain that may be specified by a well-defined, reasonably-sized set of constant values.	enum.php
exclusive specialization	(UML) See disjoint specialization.	subclass.php
external key	(UML,RM) A surrogate or substitute key that has been defined by an external organization. May be treated as a descriptive attribute in your model.	keys.php
FD, partial	See partial FD.	subkeys.php
FD, transitive	See transitive FD.	subkeys.php
foreign key (FK)	(RM,TM) A set of attributes that is copied from the PK of a parent table into the scheme of a child table.	association.php
functional dependency (FD)	(RM) Formal definition of the super key property.	subkeys.php
generalization	(UML) (noun) A superclass. (verb) The process of designing superclasses from "bottom up."	subclass.php
grant	(SQL) Statement to assign privileges to a user.	sql/ddldml.php
HAVING	(SQL) Optional clause that selects aggregated group information in a SELECT statement.	sql/functions.php
incomplete specialization	(UML) Some members of a superclass might not be members of any subclass.	subclass.php
index	(SQL) A data structure that the database uses to find records within a table more quickly.	sql/views.php
inner join	(SQL) Join of two tables with join attributes specified by the programmer.	jointypes.php
INSERT INTO	(SQL) Statement to add a row of data to a table.	tables.php
join (RA)	(RA) Formal definition on which the SQL join is based, the pairwise paste of tuples from the relations being joined. Please see full definition on the page.	sql/join.php
join (SQL)	(SQL) Operation that links two tables, specified in the FROM clause of a SELECT statement. Please see full definition on the page.	sql/join.php
join attributes	Attributes whose values are matched during the join operation.	sql/join.php
join, cross	See cross join.	jointypes.php
join, natural	See natural join.	jointypes.php
join, non-equi-	See non-equi-join.	jointypes.php
join, outer	See outer join.	jointypes.php
join, self	See self join.	jointypes.php
junction table	(RM,TM) The table created to hold the linking attributes (FKs) from both sides of a many-to-many association.	manymany.php
key	See super key.	tables.php
key, candidate	See candidate key.	keys.php
key, external	See external key.	keys.php
key, foreign	See foreign key.	association.php
key, primary	See primary key.	tables.php
key, sub	See subkey.	subkeys.php
key, substitute	See substitute key.	keys.php
key, super	See super key.	tables.php
key, surrogate	See surrogate key.	keys.php
lossless join decomposition	Decomposition (breaking apart) of a relation scheme to eliminate a subkey. The original scheme’s information can be recreated with the join in a query.	subkeys.php
many-to-many association	(UML) An association with maximum multiplicity of *..*	manymany.php
materialized view	(SQL) A view that creates and stores a result table in advance of being used.	sql/views.php
MINUS	(RA,SQL) Operation as defined in set theory, returning the difference of the tuples/rows of two relations/tables over the same scheme.	sql/setops.php
multiplicity	(UML) The minimum and maximum number of individuals of one class that may be associated with a single member of another class.	association.php
multivalued attribute	(UML) An attribute that contains more than one value from its domain. This is a design error.	hobbies.php
named query	(SQL) A view.	sql/views.php
natural join	(SQL) Join of two tables with the intersection of their schemes used as join attributes.	jointypes.php
non-equi-join	(SQL) Join based on some condition other than equality of the join attributes.	jointypes.php
normal form, third	See third normal form.	subkeys.php
normal forms	(RM) A progression of rules for well-structured database design.	normalize.php
normalization	(RM) Following a set of rules to insure that a database is well designed. See also normal forms.	subkeys.php
NULL	(SQL) A special constant value, compatible with any data type, that means "this field does not have any value assigned to it."	phone.php
object	(UML) The instantiation of a class in OO programming languages.	class.php
one-to-many association	(UML) An association with maximum multiplicity of 1..*	association.php
outer join	(SQL) Join of two tables that retains unmatched join attributes from one or both sides.	jointypes.php
overlapping specialization	(UML) Any member of a superclass may be a member of more than one subclass.	subclass.php
parent	(RM,TM) The relation on the "one" (PK) side of a one-to-many association.	association.php
partial FD	(RM) A subkey that is part of the primary key of a relation.	subkeys.php
partial specialization	(UML) See incomplete specialization.	subclass.php
paste	(RA) Tuple operation on which the RA join is based. Please see full definition on the page.	sql/join.php
predicate	(RA) Conditional statement used in the RA select operstion.	sql/queries.php
primary key (PK)	(RM,TM) The SK set of attributes that the designer picks as the unique identifier for a database table.	tables.php
project (in RA)	(RA) Unary operator that picks attributes from a relation.	sql/queries.php
property	(UML) See attribute.	class.php
query	A request to retrieve data from the database. See SELECT (SQL).	sql/queries.php
query, stored	See stored query.	sql/views.php
query, sub	See subquery.	sql/subqueries.php
recursive association	(UML) An association between a single class type (in one role) and itself (in another role).	recursive.php
referential integrity	(RM,TM) A constraint on a table that does not allow an FK value to be entered without a matching PK value.	association.php
relation	(RM) A set of tuples over the same scheme.	tables.php
relational algebra (RA)	The formal language used to sympolically manipulate objects of the RM.	models.html
relational model (RM)	The formal mathematical model of a relational database.	models.html
relationship	(ER) See association.	association.php
repeated attribute	(UML) An attribute that occurs more than once in the same class definition; it may also have attributes of its own. This is a design error.	phone.php
result set	(SQL) The intermediate table that results from execution of the FROM clause of a SELECT statement.	sql/queries.php
role	(SQL) A name for a group of database users who have been granted the same privileges.	sql/views.php
ROLLBACK	(SQL) Statement to discard changes that have not been made permanent.	sql/ddldml.php
row	(TM) The information about one individual in a database table. See also tuple.	tables.php
scheme	(RM) A set of attributes, with an assignment rule.	class.php
select (in RA)	(RA) Unary operator that picks tuples from a relation.	sql/queries.php
SELECT (in SQL)	(SQL) Statement used to retrieve data from a table.	sql/queries.php
self join	(SQL) Join of one table to itself.	jointypes.php
specialization	(UML) (noun) A subclass. (verb) The process of designing subclasses from "top down."	subclass.php
specialization constraints	(UML) Description of subclass membership (incomplete versus complete, disjoint versus overlapping).	subclass.php
specialization, complete	See complete specialization.	subclass.php
specialization, disjoint	See disjoint specialization.	subclass.php
specialization, exclusive	See disjoint specialization.	subclass.php
specialization, incomplete	See incomplete specialization.	subclass.php
specialization, overlapping	See overlapping specialization.	subclass.php
specialization, partial	See incomplete specialization.	subclass.php
stereotype	(UML) A designator before a class name that specifies the type of the class.	enum.php
stored query	(SQL) A view.	sql/views.php
structured query language (SQL)	The language used to build and manipulate relational databases.	models.html
subclass	(UML) A class that inherits common attributes from a parent class, but contains unique attributes of its own. See also superclass and specialization.	subclass.php
subkey	(RM) A set of attributes that is a super key for some, but not all, of the attributes in a relation.	subkeys.php
subquery	(SQL) A query (SELECT statement) that is embedded in another query.	sql/subqueries.php
subscheme	(RA) A subset of the attributes in a scheme, preserving the assignment rule. Used in the RA project operation.	sql/queries.php
substitute PK	(RM) An artificial, somewhat meaningful, primary key made up by the database designer under certain limited conditions. See also surrogate PK.	keys.php
SUM	(SQL) Aggregate function to sum the values in a column.	sql/functions.php
super key (SK)	(RM,TM) Any set of attributes whose values, taken together, uniquely identify each row of a table.	tables.php
superclass	(UML) A class that contains attributes common to one or more child classes. See also subclass and generalization.	subclass.php
surrogate PK	(RM) An artificial, meaningless, primary key made up by the database designer under certain limited conditions. See also substitute PK.	keys.php
table	(TM) A set of rows. See also relation.	tables.php
table model (TM)	An informal set of terms for RM objects.	models.html
third normal form (3NF)	(RM) A database with no subkey in any relation (with rare exceptions). See also normal forms.	subkeys.php
transitive FD	(RM) A subkey that is not part of the primary key of a relation.	subkeys.php
tuple	(RM) A function that assigns a constant value from the attribute domain to each attribute in a relation scheme.	tables.php
unified modeling language (UML)	An enterprise modeling tool used in database design and software engineering.	models.html
UNION	(RA,SQL) Operation as defined in set theory, returning the union of the tuples/rows of two relations/tables over the same scheme.	sql/setops.php
UPDATE	(SQL) Statement to change existing data in a table.	tables.php
validation rule	(TM) An algorithm or procedure to separate good from bad data.	domains.php
view	(SQL) Any SELECT query that has been given a name and saved in the database.	sql/views.php
view, materialized	See materialized view.	sql/views.php
weak entity	(ER) An entity (UML class) type that cannot exist without its parent entity type.	phone.php

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