WinRDBI Windows-based Relational DataBase Interpreter: WinRDBI Windows-based Relational DataBase Interpreter http://www.eas.asu.edu/~winrdbi
An educational tool that provides an interactive approach to learning relational database query languages.
Relational algebra
Domain Relational Calculus (DRC)
Tuple Relational Calculus (TRC)
SQL
WinRDBI Online Demonstrations: WinRDBI Online Demonstrations Look for online demonstrations of the software on the WinRDBI web:
http://www.eas.asu.edu/~winrdbi
Getting Started with WinRDBI
Creating a Database in WinRDBI
Additional demonstrations will be added over time.
User Interface: User Interface Multiple Query Panes: one query language is associated with each pane; result of queries displayed in the bottom subwindow of the query pane
One Schema Pane: displays the schema and instance of the currently opened relational database
ICONS: ICONS
Syntax Conventions: Syntax Conventions Since the heart of WinRDBI is written in Prolog (with Java used for the graphical user interface), the following Prolog conventions are assumed:
constants: numeric constants and single-quoted strings
relation and attribute names: identifiers starting with a lowercase letter
variable names: identifiers starting with an uppercase letter
Relational Algebra Syntax Summary: Relational Algebra Syntax Summary Fundamental Operators
(r) { t | t r and }
ai,…,aj(r) { t.ai, …, t.aj | t r }
r s { t | t r or t s }
r - s { t | t r and t s}
q × r { tqtr | tq q and tr r } Additional Operators
r s r - ( r - s )
p q (p × q)
p q P Q( (p × q) ) where = (p.ai=q.ai and … and p.aj=q.aj) P Q = {ai, …, aj}
p q P - Q (p) - P - Q ((P - Q (p) × q) - p)
Relational Algebra WinRDBI Syntax Summary: Relational Algebra WinRDBI Syntax Summary WinRDBI
select condition (r)
project ai, …, aj (r)
r union s
r difference s
q product r
r intersect s
p njoin q
: WinRDBI does not provide division and -join operators to encourage the use of the fundamental relational algebra operators. Formal Relational Algebra
condition(r)
ai,…,aj(r)
r s
r - s
q × r
r s
p q
Domain Relational Calculus Syntax Summary: Domain Relational Calculus Syntax Summary { D1, …, Dn | F (D1, …, Dn) }
F describes the properties of the data to be retrieved.
The output schema of F is given by the domain variables D1, …, Dn that act as global variables in F.
The result of the DRC expression gives the set of all tuples (d1, d2, …, dn) such that when di is substituted for Di (1 =< i =< n), F is true.
Domain Relational Calculus Atoms & Formulas: Domain Relational Calculus Atoms & Formulas Let Di be a domain variable c be a domain constant be a comparison operator
Atoms
r(D1, D2, …, Dn)
Di Dj
Di c
Let F, F1 and F2 be formulas
Formulas
( F )
not F
F1 and F2
F1 or F2 Let D be free* in F(D)
(exists D) F(D)
(forall D) F(D) * a variable is free in a formula if it is not quantified by exists or forall
Domain Relational Calculus Valid Expression: Domain Relational Calculus Valid Expression { D1, …, Dn | F (D1, …, Dn) }
is a valid DRC expression if it has only the variables appearing to the left of the vertical bar | free in F. Any other variable appearing in F must be bound.
free vs. bound variables
free (global): variable is not explicitly quantified
bound (free): variable is declared explicitly through quantification and its scope is the quantified formula
Domain Relational Calculus Relational Completeness: Domain Relational Calculus Relational Completeness condition (r): { R1, …, Rn | r(R1, …, Rn) and condition}
ai,…,aj(r):
{ Ri, …, Rj | r(R1, …, Ri, …, Rj, …, Rn)}
r s:
{ D1, …, Dn | r(D1, …, Dn) or s(D1, …, Dn) }
r - s:
{ D1, …, Dn | r(D1, …, Dn) and not s(D1, …, Dn) }
q × r :
{ Q1, …, Qm, R1, …, Rn | q(Q1, …, Qm) and r(R1, …, Rn) }
Tuple Relational Calculus Syntax Summary: Tuple Relational Calculus Syntax Summary { T1, …, Tn | F (T1, …, Tn) }
F describes the properties of the data to be retrieved.
The output schema of F is given by the tuple variables T1, …, Tn that act as global variables in F.
Tuple Relational Calculus Atoms & Formulas: Tuple Relational Calculus Atoms & Formulas Let T and Ti be tuple variables aj be an attribute c be a domain constant be a comparison operator
Atoms
r(T)
Ti.am Tj.an
T.ai c
Let F, F1 and F2 be formulas
Formulas
( F )
not F
F1 and F2
F1 or F2 Let T be free* in F(T)
(exists T) F(T)
(forall T) F(T) * a variable is free in a formula if it is not quantified by exists or forall
Tuple Relational Calculus Valid Expression: Tuple Relational Calculus Valid Expression { T1, …, Tn | F (T1, …, Tn) }
is a valid TRC expression if it has only the variables appearing to the left of the vertical bar | free in F. Any other variable appearing in F must be bound.
free vs. bound variables
free (global): variable is not explicitly quantified
bound (free): variable is declared explicitly through quantification and its scope is the quantified formula
Tuple Relational Calculus Relational Completeness: Tuple Relational Calculus Relational Completeness condition (r): { R| r(R) and condition}
ai…,aj(r):
{ R.ai, …, R.aj | r(R)}
r s:
{ T | r(T) or s(T) }
r - s:
{ T | r(T) and not s(T) }
q × r :
{ Q, R | q(Q) and r(R) }
SQL Simple Query Syntax: SQL Simple Query Syntax select distinct a1,…,am
from r1, r2, …, rn
where condition
is equivalent to
a1,…,am ( condition (r1 × r2 × … × rn) )
SQL Relational Completeness: SQL Relational Completeness condition(r)
A (r)
r s
r - s
q × r
select * from r where condition
select distinct A from r
select * from r union select * from s
select * from r except select * from s
select * from q, r
SQL Query Syntax Summary: SQL Query Syntax Summary select [distinct] ATTRIBUTE-LIST
from TABLE-LIST
[where WHERE-CONDITION]
[group by GROUPING-ATTRIBUTES
[having HAVING-CONDITION]]
[order by COLUMN-NAME [asc | desc], … ]
SQL Data Definition Syntax Summary: SQL Data Definition Syntax Summary create table TABLE-NAME
(
COL-NAME COL-TYPE [ATTR-CONSTRAINT],
…
[TABLE-CONSTRAINT-LIST]
)
where
ATTR-CONSTRAINT:
not null or default value
TABLE-CONSTRAINT-LIST:
primary key, uniqueness and referential integrity (foreign key)
SQL Insert Syntax Summary: SQL Insert Syntax Summary insert into TABLE-NAME [ (ATTRIBUTE-LIST)]
SOURCE
where SOURCE is one of:
values ( EXPLICIT-VALUES)
SELECT-STATEMENT
SQL Update & Delete Syntax Summary: SQL Update & Delete Syntax Summary
update TABLE-NAME
set COLUMN-NAME = VALUE-EXPR, …
[where UPDATE-CONDITION]
delete from TABLE-NAME
[where DELETE-CONDITION]
SQL WinRDBI Syntax Summary: SQL WinRDBI Syntax Summary Since WinRDBI has an integrated GUI for defining and manipulating the database, WinRDBI SQL supports only the query language.
SQL-89 compatibility: no joined tables in the from clause
Does not support SQL-standard view definition: assumes intermediate table syntax across all query languages
Language simplification disallows aggregation in a nested subquery: use two queries instead ...
SQL Aggregation in Nested Queries: SQL Aggregation in Nested Queries SQL
select E.eID, E.eLast, E.eFirst, E.eTitle
from employee E
where E.eSalary =
(select min(S.eSalary)
from employee S ); WinRDBI
minimumSalary(minSalary) :=
select min(E.eSalary)
from employee E;
select E.eID, E.eLast, E.eFirst, E.eTitle
from employee E
where E.eSalary =
(select minSalary
from minimumSalary);