Glossary
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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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