Andrzej Leśnicki Bazy Danych, Wykład 2010 1/28 · 2010-04-26 · Andrzej Leśnicki Bazy Danych, Wykład 2010 6/28 Nazwa Aliasy Opis precyzja 15 cyfr dziesiętnych inet IPv4 lub

Andrzej Leśnicki Bazy Danych, Wykład 2010 1/28

PostgreSQL

1. Wstęp

1.1. Czym jest PostgreSQL? Standardy języka SQL: SQL-86: ANSI X3.135-1986 „Database Language SQL” SQL-89: ANSI X3.168-1989 „Database Language - Embedded SQL” ANSI X3.135-1989 „Database Language – SQL with Integrity Enhancement” SQL-92: ISO/IEC 9075:1992 “Database Language SQL” SQL-99: ISO/IEC 9075:1999 “Information Technology – Database Languages – SQL”

DDL DML DCL TTC CREATE ALTER DROP RENAME TRUNCTATE

SELECT INSERT UPDATE DELETE

GRANT REVOKE

COMMIT ROLLBACK SAVEPOINT

PostgreSQL podtrzymuje standard SQL i oferuje wiele nowoczesnych cech:

- zapytania złożone - klucze obce - trygery (wyzwalacze) - widoki - integralność transakcyjną - sterowanie współbieżnością wielu wersji

1.2. Architektura systemu klient - serwer 1.3. Zakładanie bazy danych $ createdb student123 createdb: command not found $ /usr/local/pgsql/bin/createdb student123


$ createdb $ dropdb student123 1.4. Dostęp do bazy danych $ psql student123 student123=> student123=# student123=> \q General \copyright show PostgreSQL usage and distribution terms \g [FILE] or ; execute query (and send results to file or | pipe) \h [NAME] help on syntax of SQL commands, * for all commands \q quit psql Query Buffer \e [FILE] edit the query buffer (or file) with external editor \ef [FUNCNAME] edit function definition with external editor \p show the contents of the query buffer \r reset (clear) the query buffer \s [FILE] display history or save it to file \w FILE write query buffer to file Input/Output \copy ... perform SQL COPY with data stream to the client host \echo [STRING] write string to standard output \i FILE execute commands from file \o [FILE] send all query results to file or | pipe \qecho [STRING] write string to query output stream (see \o) Informational (options: S = show system objects, + = additional detail) \d[S+] list tables, views, and sequences \d[S+] NAME describe table, view, sequence, or index


\da[+] [PATTERN] list aggregates \db[+] [PATTERN] list tablespaces \dc[S] [PATTERN] list conversions \dC [PATTERN] list casts \dd[S] [PATTERN] show comments on objects \dD[S] [PATTERN] list domains \des[+] [PATTERN] list foreign servers \deu[+] [PATTERN] list user mappings \dew[+] [PATTERN] list foreign-data wrappers \df[antw][S+] [PATRN] list [only agg/normal/trigger/window] functions \dF[+] [PATTERN] list text search configurations \dFd[+] [PATTERN] list text search dictionaries \dFp[+] [PATTERN] list text search parsers \dFt[+] [PATTERN] list text search templates \dg[+] [PATTERN] list roles (groups) \di[S+] [PATTERN] list indexes \dl list large objects, same as \lo_list \dn[+] [PATTERN] list schemas \do[S] [PATTERN] list operators \dp [PATTERN] list table, view, and sequence access privileges \ds[S+] [PATTERN] list sequences \dt[S+] [PATTERN] list tables \dT[S+] [PATTERN] list data types \du[+] [PATTERN] list roles (users) \dv[S+] [PATTERN] list views \l[+] list all databases \z [PATTERN] same as \dp Formatting \a toggle between unaligned and aligned output mode \C [STRING] set table title, or unset if none \f [STRING] show or set field separator for unaligned query output \H toggle HTML output mode (currently off) \pset NAME [VALUE] set table output option (NAME := {format|border|expanded|fieldsep|footer|null| numericlocale|recordsep|tuples_only|title|tableattr|pager}) \t [on|off] show only rows (currently off) \T [STRING] set HTML <table> tag attributes, or unset if none \x [on|off] toggle expanded output (currently off) Connection \c[onnect] [DBNAME|- USER|- HOST|- PORT|-] connect to new database (currently "student123") \encoding [ENCODING] show or set client encoding \password [USERNAME] securely change the password for a user Operating System \cd [DIR] change the current working directory \timing [on|off] toggle timing of commands (currently off)


\! [COMMAND] execute command in shell or start interactive shell Variables \prompt [TEXT] NAME prompt user to set internal variable \set [NAME [VALUE]] set internal variable, or list all if no parameters \unset NAME unset (delete) internal variable Large Objects \lo_export LOBOID FILE \lo_import FILE [COMMENT] \lo_list \lo_unlink LOBOID large object operations

2. Opis języka

2.1. Wprowadzenie

{ }4321 ,,, ttttr = ( ) ( ) ( ) ({ }7.88,55,Wolski'',5.63,108,Dragan'',0.75,103,Jarosz'',8.55,101,'Kowalski' )

nazwisko numer_pokoju ciezar_pracownika Kowalski 101 55.8 Jarosz 103 75.0 Dragan 108 63.5 Wolski 55 88.7

znak - dane - informacja 2.2. Składnia języka CREATE TABLE --treść komentarza przedmioty(); CREATE TABLE --treść komentarza przedmioty(); lub taki zapis CREATE TABLE /*treść komentarza */ przedmioty();


Łańcuchy $function$ BEGIN RETURN ($1 ~ $q$[\t\r\n\v\\]$q$); END; $function$ Operatory + - * / < > = ~ ! @ # % ^ & | ‘ ? Operatory logiczne, to NOT, AND, OR. <> lub != not equal Znaki specjalne Typy danych

Nazwa Aliasy Opis

bigint int8 8-bajtowa liczba całkowita -9223372036854775808 do 9223372036854775807

bigserial serial8 8-bajtowa liczba naturalna z automatycznym przyrostem 1 do 9223372036854775807

bit [(n)] łańcuch bitów o stałej długości np. BIT(3) B’101’ →

bit varying [(n)] varbit łańcuch bitów o stałej długości boolean bool wartość logiczna (true/false)

box prostokąt na płaszczyźnie 32 bajty ((x1,y1),(x2,y2))

bytea dane binarne ("byte array") character varying [(n)] varchar [(n)] łańcuch znaków o zmiennej długości character [(n)] char [(n)] łańcuch znaków o stałej długości cidr IPv4 lub IPv6 adres sieciowy, 7 lub 19B

circle okrąg na płaszczyźnie, 24 bajty <(x,y),r> środek i promień

date data kalendarzowa (rok, miesiąc, dzień), 4 bajty, 4713BC do 5874897AD, dokł. 1dz

double precision float8 liczba zmiennoprzecinkowa o podwójnej precyzji (8 bajtów)


Nazwa Aliasy Opis precyzja 15 cyfr dziesiętnych

inet IPv4 lub IPv6 adres hosta, 7 lub 19B integer int, int4 4-bajtowa liczba całkowita

interval [fields] [(p)] przedział czasu, 12 bajtów, dokł. 1 , sµ-178000000 lat do 178000000 lat

line linia nieskończona na płaszczyźnie 32 bajty ((x1,y1),(x2,y2))

lseg odcinek linii na płaszczyźnie, 32 bajty, ((x1,y1),(x2,y2))

macaddr MAC (Media Access Control) adres, 6B money ilość waluty numeric [(p,s)] decimal[(p,s)] dokładna liczba o wybranej precyzji

path ścieżka geometryczna na płaszczyźnie ((x1,y1),...)

point punkt geometryczny na płaszczyźnie 16 bajtów, (x,y)

polygon zamknięta ścieżka geometryczna na płaszczyźnie ((x1,y1),...)

real float4 liczba zmiennoprzecinkowa o pojedynczej precyzji (4 bajty) precyzja 6 cyfr dziesiętnych

smallint int2 2-bajtowa liczba całkowita -32768 do +32767

serial serial4 4-bajtowa liczba naturalna z automatycznym przyrostem 1 do 2147483647

text łańcuch znaków o zmiennej długości time [(p)] [without time zone]

czas dnia (bez strefy czasu), 8 bajtów 00:00:00 do 24:00:00, dokł. 1 , 14 cyfr sµ

time [(p)] with time zone timetz czas dnia (ze strefą czasu), 12 bajtów 00:00:00+1459 do 24:00:00-1459 dokł. 1 , 14 cyfr sµ

timestamp [(p)] [without time zone]

data i czas (bez strefy czasu), 8 bajtów 4713BC do 294276AD, dokł. 1 , 14 cyfr sµ

timestamp [(p)] with time zone timestamptz data i czas (ze strefą czasu), 8 bajtów

4713BC do 294276AD, dokł.1 , 14 cyfr sµtsquery tekst szukania zapytania tsvector tekst szukania dokumentu txid_snapshot transakcja na poziomie użytkownika ID uuid universally unique identifier


Nazwa Aliasy Opis xml XML data Matematyczne operatory Operator Opis Przykład Wynik + dodawanie 2 + 3 5 - odejmowanie 2 - 3 -1 * mnożenie 2 * 3 6 / dzielenie(całkowite dzielenie obcina wynik) 4 / 2 2 % modulo (reszta) 5 % 4 1 ^ podnoszenie do potęgi 2.0 ^ 3.0 8 |/ pierwiastek kwadratowy |/ 25.0 5 ||/ pierwiastek sześcienny ||/ 27.0 3 ! silnia 5 ! 120 !! silnia (prefix operator) !! 5 120 @ wartość bezwzględna (moduł) @ -5.0 5 & bitwise AND 91 & 15 11 | bitwise OR 32 | 3 35 # bitwise XOR 17 # 5 20 ~ bitwise NOT ~1 -2 << bitwise shift left 1 << 4 16 >> bitwise shift right 8 >> 2 2

( ) ( )210 10000032 = ( ) ( )210 113 = Funkcje matematyczne

Funkcja Zwraca Typ Opis Przykład Wynik

abs(x) (same as input)

wartość bezwzględna

abs(-17.4) 17.4

cbrt(dp) dp 3 cbrt(27.0) 3

ceil(dp or numeric)

(same as input)

najmniejsza liczba całkowita nie mniejsza niż argument

ceil(-42.8) -42

ceiling(dp or numeric)

(taki sam jak typ alias dla ceil ceiling(-95.3) -95



wejścia)

degrees(dp) dp radiany na stopnie

degrees(0.5) 28.6478897565412

div(y numeric, x numeric) numeric Część całkowita

z y/x div(9,4) 2

exp(dp or numeric)

(taki sam jak typ wejścia)

exponential exp(1.0) 2.71828182845905

floor(dp or numeric)


największa liczba całkowita nie większa niż argument

floor(-42.8) -43

ln(dp or numeric)


naturalny logarytm

ln(2.0) 0.693147180559945

log(dp or numeric)


podstawa 10 logarytm

log(100.0) 2

log(b numeric, x numeric) numeric logarytm o

podstawie b log(2.0, 64.0) 6.0000000000

mod(y, x) (taki sam jak typ wejścia)

reszta z y/x modulo mod(9,4) 1

pi() dp stała "π" pi() 3.14159265358979 power(a dp, b dp) dp potęga a b power(9.0, 3.0) 729

power(a numeric, b numeric) numeric potęga a b power(9.0, 3.0) 729

radians(dp) dp stopnie na radiany

radians(45.0) 0.785398163397448

random() dp Wartość przypadkowa z przedziału 0.0 <= x < 1.0

random()

round(dp or numeric)


zaokrąglenie do najbliższej liczby całkowitej

round(42.4) 42

round(v numeric, s int) numeric

zaokrąglenie do s-tego miejsca po przecinku

round(42.4382, 2) 42.44

setseed(dp) void ziarno dla funkcji

setseed(0.54823)



random() (wartość pomiędzy -1.0 and 1.0, włącznie)

sign(dp or numeric)


znak argumentu (-1, 0, +1)

sign(-8.4) -1

sqrt(dp or numeric)


2 sqrt(2.0) 1.4142135623731

trunc(dp or numeric)


Obcięcie w kierunku zera

trunc(42.8) 42

trunc(v numeric, s int) numeric

Obcięcie do s-tego miejsca po przecinku

trunc(42.4382, 2) 42.43

width_bucket(op numeric, b1 numeric, b2 numeric, count int)

int

return the bucket to which operand would be assigned in an equidepth histogram with count buckets, in the range b1 to b2

width_bucket(5.35, 0.024, 10.06, 5)

3

width_bucket(op dp, b1 dp, b2 dp, count int)

int

return the bucket to which operand would be assigned in an equidepth histogram with count buckets, in the range b1 to b2

width_bucket(5.35, 0.024, 10.06, 5)

3

Funkcje trygonometryczne

Funkcja Opis acos(x) arcus cos asin(x) arcus sin atan(x) arcus tangens atan2(y, x) arcus tangens z y/x


Funkcja Opis cos(x) cos cot(x) cotangents sin(x) sin tan(x) tangens Funkcje agregujące ogólnego przeznaczenia


Funkcja Argumentu Typ Zwraca Typ Opis

array_agg(expression) any array of the argument type input values concatenated into an array

avg(expression)

smallint, int, bigint, real, double precision, numeric, or interval

numeric for any integer-type argument, double precision for a floating-point argument, otherwise the same as the argument data type

the average (arithmetic mean) of all input values

bit_and(expression) smallint, int, bigint, or bit

same as argument data type

the bitwise AND of all non-null input values, or null if none

bit_or(expression) smallint, int, bigint, or bit


the bitwise OR of all non-null input values, or null if none

bool_and(expression) bool bool true if all input values are true, otherwise false

bool_or(expression) bool bool true if at least one input value is true, otherwise false

count(*) bigint number of input rows

count(expression) any bigint

number of input rows for which the value of expression is not null

every(expression) bool bool equivalent to bool_and

max(expression) any array, numeric, string, or date/time type

same as argument type maximum value of expression across all input values

min(expression) any array, numeric, string, or date/time type

same as argument type minimum value of expression across all input values

sum(expression)


bigint for smallint or int arguments, numeric for bigint arguments, double precision for floating-point arguments, otherwise the same as the argument data type

sum of expression across all input values

xmlagg(expression) xml xml concatenation of XML values


Funkcje agregujące dla statystyki


corr(Y, X) double precision

double precision correlation coefficient

covar_pop(Y, X) double precision

double precision population covariance

covar_samp(Y, X) double precision

double precision sample covariance

regr_avgx(Y, X) double precision

double precision

average of the independent variable (sum(X)/N)

regr_avgy(Y, X) double precision

double precision

average of the dependent variable (sum(Y)/N)

regr_count(Y, X) double precision bigint

number of input rows in which both expressions are nonnull

regr_intercept(Y, X) double precision

double precision

y-intercept of the least-squares-fit linear equation determined by the (X, Y) pairs

regr_r2(Y, X) double precision

double precision

square of the correlation coefficient

regr_slope(Y, X) double precision

double precision

slope of the least-squares-fit linear equation determined by the (X, Y) pairs

regr_sxx(Y, X) double precision

double precision

sum(X^2) - sum(X)^2/N ("sum of squares" of the independent variable)

regr_sxy(Y, X) double precision

double precision

sum(X*Y) - sum(X) * sum(Y)/N ("sum of products" of independent times dependent variable)

regr_syy(Y, X) double precision

double precision

sum(Y^2) - sum(Y)^2/N ("sum of squares" of the dependent variable)

stddev(expression) smallint, int, bigint, real, double precision, or

double precision for floating-point arguments,

historical alias for stddev_samp


Funkcja Argumentu Typ Zwraca Typ Opis numeric otherwise

numeric

stddev_pop(expression)

smallint, int, bigint, real, double precision, or numeric

double precision for floating-point arguments, otherwise numeric

population standard deviation of the input values

stddev_samp(expression)



sample standard deviation of the input values

variance(expression)



historical alias for var_samp

var_pop(expression)



population variance of the input values (square of the population standard deviation)

var_samp(expression)



sample variance of the input values (square of the sample standard deviation)


Funkcje systemu informatycznego

Nazwa Zwraca Typ Opis

current_catalog name name of current database (called "catalog" in the SQL standard)

current_database() name name of current database current_schema[()] name name of current schema

current_schemas(boolean) name[] names of schemas in search path optionally including implicit schemas

current_user name user name of current execution context

current_query text text of the currently executing query, as submitted by the client (might contain more than one statement)

pg_backend_pid() int Process ID of the server process attached to the current session

inet_client_addr() inet address of the remote connection inet_client_port() int port of the remote connection inet_server_addr() inet address of the local connection inet_server_port() int port of the local connection

pg_my_temp_schema() oid OID of session's temporary schema, or 0 if none

pg_is_other_temp_schema(oid) boolean is schema another session's temporary schema?

pg_postmaster_start_time() timestamp with time zone

server start time

pg_conf_load_time() timestamp with time zone

configuration load time

session_user name session user name user name equivalent to current_user version() text PostgreSQL version information

Funkcje daty/czasu


age(timestamp, timestamp) interval

Odejmuje argumenty, dając “symboliczny” wynik z latami i miesiącami

age(timestamp '2001-04-10', timestamp '1957-06-13')

43 years 9 mons 27 days



age(timestamp) interval Odejmuje od current_date (o północy)

age(timestamp '1957-06-13')

43 years 8 mons 3 days

clock_timestamp() timestamp with time zone

Bieżąca data i czas (zmienia się w trakcie wykonywania polecenia)

current_date date Bieżąca data

current_time time with time zone Bieżący czas dnia

current_timestamp timestamp with time zone

Bieżąca data i czas (początek bieżącej transakcji)

date_part(text, timestamp) double precision Pobranie podpola (równoważne extract)

date_part('hour', timestamp '2001-02-16 20:38:40')

20

date_part(text, interval) double precision

Pobranie podpola (równoważne extract)

date_part('month', interval '2 years 3 months')

3

date_trunc(text, timestamp) timestamp Obcięcie do

zadanej precyzji date_trunc('hour', timestamp '2001-02-16 20:38:40')

2001-02-16 20:00:00

extract(field from timestamp)

double precision Pobranie podpola

extract(hour from timestamp '2001-02-16 20:38:40')

20

extract(field from interval)

double precision Pobranie podpola

extract(month from interval '2 years 3 months')

3

isfinite(date) boolean Testowanie, czy data jest skończona (not +/-infinity)

isfinite(date '2001-02-16') true

isfinite(timestamp) boolean Testowanie, czy jest skończony stempel czasu (not +/-infinity)

isfinite(timestamp '2001-02-16 21:28:30') true

isfinite(interval) boolean Testowanie, czy jest skończony przedział

isfinite(interval '4 hours') true

justify_days(interval) interval

Uporządkuj przedział tak, aby okresy 38-dniowe były przedst. jako miesiące

justify_days(interval '35 days')

1 mon 5 days



justify_hours(interval) interval

Uporządkuj przedział tak, aby okresy 24-godz. były przedst. jako dni

justify_hours(interval '27 hours')

1 day 03:00:00

justify_interval(interval) interval

Uporządkuj przedział używając justify_days i justify_hours, z dodatkowym znakiem uporządkowania

justify_interval(interval '1 mon -1 hour')

29 days 23:00:00

localtime time Bieżący lokalny czas dnia

localtimestamp timestamp Bieżąca data i lokalny czas (początek bieżącej transakcji)

now() timestamp with time zone

Bieżąca data i lokalny czas (początek bieżącej transakcji)

statement_timestamp() timestamp with time zone

Bieżąca data i lokalny czas (początek bieżącego polecenia)

timeofday() text

Bieżąca data i czas (podobnie jak clock_timestamp, ale z łańcuchem tekstu)

transaction_timestamp() timestamp with time zone

Bieżąca data i czas (początek bieżącej transakcji)

2.3. Zakładanie tabeli CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE table_name ( [ { column_name data_type [ DEFAULT default_expr ] [ column_constraint [ ... ] ] | table_constraint | LIKE parent_table [ { INCLUDING | EXCLUDING } { DEFAULTS | CONSTRAINTS | INDEXES } ] ... } [, ... ]


] ) [ INHERITS ( parent_table [, ... ] ) ] [ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ] [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ] [ TABLESPACE tablespace ] where column_constraint is: [ CONSTRAINT constraint_name ] { NOT NULL | NULL | UNIQUE index_parameters | PRIMARY KEY index_parameters | CHECK ( expression ) | REFERENCES reftable [ ( refcolumn ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE action ] [ ON UPDATE action ] } [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] and table_constraint is: [ CONSTRAINT constraint_name ] { UNIQUE ( column_name [, ... ] ) index_parameters | PRIMARY KEY ( column_name [, ... ] ) index_parameters | CHECK ( expression ) | FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE action ] [ ON UPDATE action ] } [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ] index_parameters in UNIQUE and PRIMARY KEY constraints are: [ WITH ( storage_parameter [= value] [, ... ] ) ] [ USING INDEX TABLESPACE tablespace ] lub w skrócie: CREATE TABLE <table name> (<column definition> [,...<last column definition] [<primary key definition>] [<foreign key definition>]); <column definition> jest zdefiniowane następująco: <column name> <data-type> [DEFAULT <value>] [NOT NULL] [UNIQUE] [<check constraint definition>] <check constraint definition> jest zdefiniowane następująco: CHECK (<search condition>) <primary key definition> jest zdefiniowane następująco: PRIMARY KEY (<column name> [, <column name>]) <foreign key definition> jest zdefiniowane następująco: FOREIGN KEY (<column name>) REFERENCES <table name>


DROP TABLE zabawki; DROP TABLE dzieci; 2.4. Modyfikowanie tabeli ALTER TABLE [ ONLY ] name [ * ] action [, ... ] ALTER TABLE [ ONLY ] name [ * ] RENAME [ COLUMN ] column TO new_column ALTER TABLE name RENAME TO new_name ALTER TABLE name SET SCHEMA new_schema where action is one of: ADD [ COLUMN ] column type [ column_constraint [ ... ] ] DROP [ COLUMN ] column [ RESTRICT | CASCADE ] ALTER [ COLUMN ] column [ SET DATA ] TYPE type [ USING expression ] ALTER [ COLUMN ] column SET DEFAULT expression ALTER [ COLUMN ] column DROP DEFAULT ALTER [ COLUMN ] column { SET | DROP } NOT NULL ALTER [ COLUMN ] column SET STATISTICS integer ALTER [ COLUMN ] column SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN } ADD table_constraint DROP CONSTRAINT constraint_name [ RESTRICT | CASCADE ] DISABLE TRIGGER [ trigger_name | ALL | USER ] ENABLE TRIGGER [ trigger_name | ALL | USER ] ENABLE REPLICA TRIGGER trigger_name ENABLE ALWAYS TRIGGER trigger_name DISABLE RULE rewrite_rule_name ENABLE RULE rewrite_rule_name ENABLE REPLICA RULE rewrite_rule_name ENABLE ALWAYS RULE rewrite_rule_name CLUSTER ON index_name SET WITHOUT CLUSTER SET WITH OIDS SET WITHOUT OIDS SET ( storage_parameter = value [, ... ] ) RESET ( storage_parameter [, ... ] ) INHERIT parent_table NO INHERIT parent_table OWNER TO new_owner SET TABLESPACE new_tablespace ALTER TABLE foo ALTER COLUMN foo_timestamp SET DATA TYPE timestamp with time zone USING timestamp with time zone 'epoch' + foo_timestamp * interval '1 second';


2.5. Wstawianie i modyfikowanie danych w tabeli INSERT INTO table [ ( column [, ...] ) ] { DEFAULT VALUES | VALUES ( { expression | DEFAULT } [, ...] ) [, ...] | query } [ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ] COPY tablename [ ( column [, ...] ) ] FROM { 'filename' | STDIN } [ [ WITH ] [ BINARY ] [ OIDS ] [ DELIMITER [ AS ] 'delimiter' ] [ NULL [ AS ] 'null string' ] [ CSV [ HEADER ] [ QUOTE [ AS ] 'quote' ] [ ESCAPE [ AS ] 'escape' ] [ FORCE NOT NULL column [, ...] ] COPY { tablename [ ( column [, ...] ) ] | ( query ) } TO { 'filename' | STDOUT } [ [ WITH ] [ BINARY ] [ OIDS ] [ DELIMITER [ AS ] 'delimiter' ] [ NULL [ AS ] 'null string' ] [ CSV [ HEADER ] [ QUOTE [ AS ] 'quote' ] [ ESCAPE [ AS ] 'escape' ] [ FORCE QUOTE column [, ...] ] UPDATE [ ONLY ] table [ [ AS ] alias ] SET { column = { expression | DEFAULT } | ( column [, ...] ) = ( { expression | DEFAULT } [, ...] ) } [, ...] [ FROM fromlist ] [ WHERE condition | WHERE CURRENT OF cursor_name ] [ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ] 2.6. Zapytania SELECT [ WITH [ RECURSIVE ] with_query [, ...] ] SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ] * | expression [ [ AS ] output_name ] [, ...] [ FROM from_item [, ...] ] [ WHERE condition ] [ GROUP BY expression [, ...] ] [ HAVING condition [, ...] ] [ WINDOW window_name AS ( window_definition ) [, ...] ] [ { UNION | INTERSECT | EXCEPT } [ ALL ] select ] [ ORDER BY expression [ ASC | DESC | USING operator ] [ NULLS { FIRST | LAST } ] [, ...] ] [ LIMIT { count | ALL } ] [ OFFSET start [ ROW | ROWS ] ]


[ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY ] [ FOR { UPDATE | SHARE } [ OF table_name [, ...] ] [ NOWAIT ] [...] ] where from_item can be one of: [ ONLY ] table_name [ * ] [ [ AS ] alias [ ( column_alias [, ...] ) ] ] ( select ) [ AS ] alias [ ( column_alias [, ...] ) ] with_query_name [ [ AS ] alias [ ( column_alias [, ...] ) ] ] function_name ( [ argument [, ...] ] ) [ AS ] alias [ ( column_alias [, ...] | column_definition [, ...] ) ] function_name ( [ argument [, ...] ] ) AS ( column_definition [, ...] ) from_item [ NATURAL ] join_type from_item [ ON join_condition | USING ( join_column [, ...] ) ] and with_query is: with_query_name [ ( column_name [, ...] ) ] AS ( select ) TABLE { [ ONLY ] table_name [ * ] | with_query_name } Cross join (złączenie krzyżowe) T1 CROSS JOIN T2 Qualified joins (kwalifikowane złączenia) T1 {[INNER]|{LEFT|RIGHT|FULL}[OUTER]} JOIN T2 ON boolean_expression

T1 {[INNER]|{LEFT|RIGHT|FULL}[OUTER]} JOIN T2 USING (join column list) T1 NATURAL {[INNER]|{LEFT|RIGHT|FULL}[OUTER]} JOIN T2

<SELECT . . . > UNION[ALL] <SELECT . . . > <SELECT . . . > INTERSECT[ALL] <SELECT . . . > <SELECT . . . > EXCEPT[ALL] <SELECT . . . > 2.7. Widoki (perspektywy) CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW name [ ( column_name [, ...] ) ] AS query ALTER VIEW name ALTER [ COLUMN ] column SET DEFAULT expression ALTER VIEW name ALTER [ COLUMN ] column DROP DEFAULT ALTER VIEW name OWNER TO new_owner ALTER VIEW name RENAME TO new_name ALTER VIEW name SET SCHEMA new_schema


DROP VIEW [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ] 2.8. Operatory i funkcje Operatory logiczne i porównania

a b a AND b a OR b TRUE TRUE TRUE TRUE TRUE FALSE FALSE TRUE TRUE NULL NULL TRUE FALSE FALSE FALSE FALSE FALSE NULL FALSE NULL NULL NULL NULL NULL

a NOT a TRUE FALSE FALSE TRUE NULL NULL Operator Description < less than > greater than <= less than or equal to >= greater than or equal to = equal <> or != not equal expression IS NULL expression IS NOT NULL expression ISNULL expression NOTNULL expression IS DISTINCT FROM expression expression IS NOT DISTINCT FROM expression


expression IS TRUE expression IS NOT TRUE expression IS FALSE expression IS NOT FALSE expression IS UNKNOWN expression IS NOT UNKNOWN

Funkcje agregujące



array_agg(expression) any array of the argument type input values concatenated into an array

avg(expression)


numeric for any integer-type argument, double precision for a floating-point argument, otherwise the same as the argument data type

the average (arithmetic mean) of all input values

bit_and(expression) smallint, int, bigint, or bit


the bitwise AND of all non-null input values, or null if none

bit_or(expression) smallint, int, bigint, or bit


the bitwise OR of all non-null input values, or null if none

bool_and(expression) bool bool true if all input values are true, otherwise false

bool_or(expression) bool bool true if at least one input value is true, otherwise false

count(*) bigint number of input rows

count(expression) any bigint

number of input rows for which the value of expression is not null

every(expression) bool bool equivalent to bool_and

max(expression) any array, numeric, string, or date/time type

same as argument type maximum value of expression across all input values

min(expression) any array, numeric, string, or date/time type

same as argument type minimum value of expression across all input values

sum(expression)


bigint for smallint or int arguments, numeric for bigint arguments, double precision for floating-point arguments, otherwise the same as the argument data type

sum of expression across all input values

xmlagg(expression) xml xml concatenation of XML values


Funkcje definiowane przez użytkownika CREATE [ OR REPLACE ] FUNCTION name ( [ [ argmode ] [ argname ] argtype [ { DEFAULT | = } defexpr ] [, ...] ] ) [ RETURNS rettype | RETURNS TABLE ( colname coltype [, ...] ) ] { LANGUAGE langname | WINDOW | IMMUTABLE | STABLE | VOLATILE | CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT | [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER | COST execution_cost | ROWS result_rows | SET configuration_parameter { TO value | = value | FROM CURRENT } | AS 'definition' | AS 'obj_file', 'link_symbol' } ... [ WITH ( attribute [, ...] ) ] ALTER FUNCTION name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) RENAME TO new_name ALTER FUNCTION name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) OWNER TO new_owner DROP FUNCTION [ IF EXISTS ] name ( [ [ argmode ] [ argname ] argtype [, ...] ] ) [ CASCADE | RESTRICT ] 2.9. Wyzwalacze CREATE TRIGGER name { BEFORE | AFTER } { event [ OR ... ] } ON table [ FOR [ EACH ] { ROW | STATEMENT } ] EXECUTE PROCEDURE funcname ( arguments ) : CREATE TRIGGER trigbefore BEFORE INSERT OR UPDATE OR DELETE ON tabtest FOR EACH ROW EXECUTE PROCEDURE funkcja_wyzwalacza( ); : CREATE TRIGGER trigafter AFTER INSERT OR UPDATE OR DELETE ON tabtest FOR EACH ROW EXECUTE PROCEDURE funkcja_wyzwalacza( );


ALTER TRIGGER name ON table RENAME TO newname DROP TRIGGER [ IF EXISTS ] name ON table [ CASCADE | RESTRICT ] Faza

Wydarzenie BEFORE

AFTER

INSERT

Jest możliwe zawetowanie wstawienia. Wstawiane wartości są dostępne w rekordzie NEW. Modyfikowanie zawartości NEW spowoduje wstawienie zmodyfikowanych danych. W przypadku braku weta funkcja wyzwalacza powinna zwrócić NEW.

Dane znajdują się już fizycznie w tabeli. Wstawione dane są dostępne w rekordzie NEW.

UPDATE

Jest możliwe zawetowanie uaktualnienia. Stare wartości są dostępne w rekordzie OLD, a nowe w NEW. Modyfikowanie zawartości NEW spowoduje wstawienie zmodyfikowanych danych. W przypadku braku weta funkcja wyzwalacza powinna zwrócić NEW.

Dane znajdują się już fizycznie w tabeli. Wstawione dane są dostępne w rekordzie NEW, stare są dostępne w OLD.

DELETE

Jest możliwe zawetowanie usunięcia. Nie ma możliwości uaktualnienia zamiast usunięcia. Skasowane wartości są dostępne w rekordzie OLD.

Rekord jest już fizycznie skasowany. Pola skasowanego rekordu są dostępne w OLD.

2.10. Transakcje Aby ułatwić zapamiętanie warunków jakie ma spełniać bezpieczna transakcja, warunki te nazwano w skrócie ACID (z ang. Atomic, Consistent, Isolated, Durable), czyli transakcja ma być atomowa, spójna, izolowana, trwała. BEGIN [ WORK | TRANSACTION ] [ transaction_mode [, ...] ] where transaction_mode is one of:

ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED }

READ WRITE | READ ONLY


START TRANSACTION [ transaction_mode [, ...] ] where transaction_mode is one of: ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED } READ WRITE | READ ONLY SET TRANSACTION transaction_mode [, ...] SET SESSION CHARACTERISTICS AS TRANSACTION transaction_mode [, ...] where transaction_mode is one of: ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED } READ WRITE | READ ONLY COMMIT [ WORK | TRANSACTION ] END [ WORK | TRANSACTION ] ROLLBACK [ WORK | TRANSACTION ] ROLLBACK [ WORK | TRANSACTION ] TO [ SAVEPOINT ] savepoint_name SAVEPOINT savepoint_name 2.11. Bezpieczeństwo w SQL ALTER TABLE table_name OWNER TO new_owner ; GRANT UPDATE ON pracownicy TO student123 ; GRANT ALL ON pracownicy TO PUBLIC ; REVOKE UPDATE ON pracownicy FROM student123 ; REVOKE ALL ON pracownicy FROM PUBLIC ; GRANT { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER } [,...] | ALL [ PRIVILEGES ] } ON [ TABLE ] tablename [, ...] TO { [ GROUP ] rolename | PUBLIC } [, ...] [ WITH GRANT OPTION ] GRANT { { SELECT | INSERT | UPDATE | REFERENCES } ( column [, ...] ) [,...] | ALL [ PRIVILEGES ] ( column [, ...] ) }


ON [ TABLE ] tablename [, ...] TO { [ GROUP ] rolename | PUBLIC } [, ...] [ WITH GRANT OPTION ] GRANT { { CREATE | CONNECT | TEMPORARY | TEMP } [,...] | ALL [ PRIVILEGES ] } ON DATABASE dbname [, ...] TO { [ GROUP ] rolename | PUBLIC } [, ...] [ WITH GRANT OPTION ] GRANT { EXECUTE | ALL [ PRIVILEGES ] } ON FUNCTION funcname ( [ [ argmode ] [ argname ] argtype [, ...] ] ) [, ...] TO { [ GROUP ] rolename | PUBLIC } [, ...] [ WITH GRANT OPTION ] GRANT { USAGE | ALL [ PRIVILEGES ] } ON LANGUAGE langname [, ...] TO { [ GROUP ] rolename | PUBLIC } [, ...] [ WITH GRANT OPTION ] REVOKE [ GRANT OPTION FOR ] { { SELECT | INSERT | UPDATE | DELETE | TRUNCATE | REFERENCES | TRIGGER } [,...] | ALL [ PRIVILEGES ] } ON [ TABLE ] tablename [, ...] FROM { [ GROUP ] rolename | PUBLIC } [, ...] [ CASCADE | RESTRICT ] REVOKE [ GRANT OPTION FOR ] { { SELECT | INSERT | UPDATE | REFERENCES } ( column [, ...] ) [,...] | ALL [ PRIVILEGES ] ( column [, ...] ) } ON [ TABLE ] tablename [, ...] FROM { [ GROUP ] rolename | PUBLIC } [, ...] [ CASCADE | RESTRICT ] REVOKE [ GRANT OPTION FOR ] { { CREATE | CONNECT | TEMPORARY | TEMP } [,...] | ALL [ PRIVILEGES ] } ON DATABASE dbname [, ...] FROM { [ GROUP ] rolename | PUBLIC } [, ...] [ CASCADE | RESTRICT ] REVOKE [ GRANT OPTION FOR ] { EXECUTE | ALL [ PRIVILEGES ] } ON FUNCTION funcname ( [ [ argmode ] [ argname ] argtype [, ...] ] ) [, ...] FROM { [ GROUP ] rolename | PUBLIC } [, ...] [ CASCADE | RESTRICT ] REVOKE [ GRANT OPTION FOR ] { USAGE | ALL [ PRIVILEGES ] } ON LANGUAGE langname [, ...] FROM { [ GROUP ] rolename | PUBLIC } [, ...] [ CASCADE | RESTRICT ]


2.12. Indeksy CREATE TABLE zabawki ( numer_zabawki int , nazwa_zabawki text , cena numeric ) ; SELECT nazwa_zabawki FROM zabawki WHERE cena<20 ; CREATE INDEX zabawki_cena_indeks ON zabawki(cena); CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] name ON table [ USING method ] ( { column | ( expression ) } [ opclass ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] ) [ WITH ( storage_parameter = value [, ... ] ) ] [ TABLESPACE tablespace ] [ WHERE predicate ] ALTER INDEX name RENAME TO new_name ALTER INDEX name SET TABLESPACE tablespace_name ALTER INDEX name SET ( storage_parameter = value [, ... ] ) ALTER INDEX name RESET ( storage_parameter [, ... ] ) DROP INDEX [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ] 2.13. Kursory DECLARE name [ BINARY ] [ INSENSITIVE ] [ [ NO ] SCROLL ] CURSOR [ { WITH | WITHOUT } HOLD ] FOR query FETCH [ direction { FROM | IN } ] cursorname where direction can be empty or one of: NEXT PRIOR FIRST LAST ABSOLUTE n RELATIVE n count ALL FORWARD FORWARD n FORWARD ALL BACKWARD BACKWARD n BACKWARD ALL MOVE [ direction { FROM | IN } ] cursorname MOVE n CLOSE { name | ALL }

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