Glossary

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Glossary
keyworddefinitionpage_link
scheme(RM) A set of attributes, with an assignment rule.class.php
select (in RA)(RA) Unary operator that picks tuples from a relation.queries.php
SELECT (in SQL)(SQL) Statement used to retrieve data from a table.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, completeSee complete specialization.subclass.php
specialization, disjointSee disjoint specialization.subclass.php
specialization, exclusiveSee disjoint specialization.subclass.php
specialization, incompleteSee incomplete specialization.subclass.php
specialization, overlappingSee overlapping specialization.subclass.php
specialization, partialSee 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.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.subqueries.php
subscheme(RA) A subset of the attributes in a scheme, preserving the assignment rule. Used in the RA project operation.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.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.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.views.php
view, materializedSee materialized view.views.php
weak entity(ER) An entity (UML class) type that can't exist without its parent entity type.phone.php

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