PostgreSQL 系统表查看系统信息

lzf79

摘自http://www.alberton.info/postgresql_meta_info.html
测试数据

-- sample data to test PostgreSQL INFORMATION_SCHEMA
-- TABLE TEST
CREATE TABLE TEST (
TEST_NAME CHAR(30) NOT NULL,
TEST_ID INTEGER DEFAULT '0' NOT NULL,
TEST_DATE TIMESTAMP NOT NULL
);
ALTER TABLE TEST ADD CONSTRAINT PK_TEST PRIMARY KEY (TEST_ID);
-- TABLE TEST2 with some CONSTRAINTs and an INDEX
CREATE TABLE TEST2 (
ID INTEGER NOT NULL,
FIELD1 INTEGER,
FIELD2 CHAR(15),
FIELD3 VARCHAR(50),
FIELD4 INTEGER,
FIELD5 INTEGER,
ID2 INTEGER NOT NULL
);
ALTER TABLE TEST2 ADD CONSTRAINT PK_TEST2 PRIMARY KEY (ID2);
ALTER TABLE TEST2 ADD CONSTRAINT TEST2_FIELD1ID_IDX UNIQUE (ID, FIELD1);
ALTER TABLE TEST2 ADD CONSTRAINT TEST2_FIELD4_IDX UNIQUE (FIELD4);
CREATE INDEX TEST2_FIELD5_IDX ON TEST2(FIELD5);
-- TABLE NUMBERS
CREATE TABLE NUMBERS (
NUMBER INTEGER DEFAULT '0' NOT NULL,
EN CHAR(100) NOT NULL,
FR CHAR(100) NOT NULL
);
-- TABLE NEWTABLE
CREATE TABLE NEWTABLE (
ID INT DEFAULT 0 NOT NULL,
SOMENAME VARCHAR (12),
SOMEDATE TIMESTAMP NOT NULL
);
ALTER TABLE NEWTABLE ADD CONSTRAINT PKINDEX_IDX PRIMARY KEY (ID);
CREATE SEQUENCE NEWTABLE_SEQ INCREMENT 1 START 1;
-- VIEW on TEST
CREATE VIEW "testview"(
TEST_NAME,
TEST_ID,
TEST_DATE
) AS
SELECT *
FROM TEST
WHERE TEST_NAME LIKE 't%';
-- VIEW on NUMBERS
CREATE VIEW "numbersview"(
NUMBER,
TRANS_EN,
TRANS_FR
) AS
SELECT *
FROM NUMBERS
WHERE NUMBER > 100;
-- TRIGGER on NEWTABLE
CREATE FUNCTION add_stamp() RETURNS OPAQUE AS '
BEGIN
IF (NEW.somedate IS NULL OR NEW.somedate = 0) THEN
NEW.somedate := CURRENT_TIMESTAMP;
RETURN NEW;
END IF;
END;
' LANGUAGE 'plpgsql';
CREATE TRIGGER ADDCURRENTDATE
BEFORE INSERT OR UPDATE
ON newtable FOR EACH ROW
EXECUTE PROCEDURE add_stamp();
-- TABLEs for testing CONSTRAINTs
CREATE TABLE testconstraints (
someid integer NOT NULL,
somename character varying(10) NOT NULL,
CONSTRAINT testconstraints_id_pk PRIMARY KEY (someid)
);
CREATE TABLE testconstraints2 (
ext_id integer NOT NULL,
modified date,
uniquefield character varying(10) NOT NULL,
usraction integer NOT NULL,
CONSTRAINT testconstraints_id_fk FOREIGN KEY (ext_id)
REFERENCES testconstraints (someid) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE CASCADE,
CONSTRAINT unique_2_fields_idx UNIQUE (modified, usraction),
CONSTRAINT uniquefld_idx UNIQUE (uniquefield)
);

列出所有数据库中的表名

SELECT relname
FROM pg_class
WHERE relname !~ '^(pg_|sql_)'
AND relkind = 'r';
<!--
SELECT c.relname AS "Name"
FROM pg_class c, pg_user u
WHERE c.relowner = u.usesysid
AND c.relkind = 'r'
AND NOT EXISTS (
SELECT 1
FROM pg_views
WHERE viewname = c.relname
)
AND c.relname !~ '^(pg_|sql_)'
UNION
SELECT c.relname AS "Name"
FROM pg_class c
WHERE c.relkind = 'r'
AND NOT EXISTS (
SELECT 1
FROM pg_views
WHERE viewname = c.relname
)
AND NOT EXISTS (
SELECT 1
FROM pg_user
WHERE usesysid = c.relowner
)
AND c.relname !~ '^pg_';
-->
-- using INFORMATION_SCHEMA:
SELECT table_name
FROM information_schema.tables
WHERE table_type = 'BASE TABLE'
AND table_schema NOT IN
('pg_catalog', 'information_schema');

列出所有视图

-- with postgresql 7.2:
SELECT viewname
FROM pg_views
WHERE viewname !~ '^pg_';
-- with postgresql 7.4 and later:
SELECT viewname
FROM pg_views
WHERE schemaname NOT IN
('pg_catalog', 'information_schema')
AND viewname !~ '^pg_';
-- using INFORMATION_SCHEMA:
SELECT table_name
FROM information_schema.tables
WHERE table_type = 'VIEW'
AND table_schema NOT IN
('pg_catalog', 'information_schema')
AND table_name !~ '^pg_';
-- or
SELECT table_name
FROM information_schema.views
WHERE table_schema NOT IN ('pg_catalog', 'information_schema')
AND table_name !~ '^pg_';
<!--
# show only the VIEWs referencing a given table
SELECT viewname
FROM pg_views
NATURAL JOIN pg_tables
WHERE tablename ='test';
-->

列出所有用户

SELECT usename
FROM pg_user;

列出某表中得所有字段

SELECT a.attname
FROM pg_class c, pg_attribute a, pg_type t
WHERE c.relname = 'test2'
AND a.attnum > 0
AND a.attrelid = c.oid
AND a.atttypid = t.oid
-- with INFORMATION_SCHEMA:
SELECT column_name
FROM information_schema.columns
WHERE table_name = 'test2';

列出某表字段的信息

SELECT a.attnum AS ordinal_position,
a.attname AS column_name,
t.typname AS data_type,
a.attlen AS character_maximum_length,
a.atttypmod AS modifier,
a.attnotnull AS notnull,
a.atthasdef AS hasdefault
FROM pg_class c,
pg_attribute a,
pg_type t
WHERE c.relname = 'test2'
AND a.attnum > 0
AND a.attrelid = c.oid
AND a.atttypid = t.oid
ORDER BY a.attnum;
-- with INFORMATION_SCHEMA:
SELECT ordinal_position,
column_name,
data_type,
column_default,
is_nullable,
character_maximum_length,
numeric_precision
FROM information_schema.columns
WHERE table_name = 'test2'
ORDER BY ordinal_position;

List INDICES
Here's the query that will return the names of the INDICES defined in the TEST2 table. Unfortunately I have no idea how to extract them from the INFORMATION_SCHEMA. If you do, please let me know.
NB: the CONSTRAINTs are not listed

SELECT relname
FROM pg_class
WHERE oid IN (
SELECT indexrelid
FROM pg_index, pg_class
WHERE pg_class.relname='test2'
AND pg_class.oid=pg_index.indrelid
AND indisunique != 't'
AND indisprimary != 't'
);


列出表的索引信息

SELECT relname, indkey
FROM pg_class, pg_index
WHERE pg_class.oid = pg_index.indexrelid
AND pg_class.oid IN (
SELECT indexrelid
FROM pg_index, pg_class
WHERE pg_class.relname='test2'
AND pg_class.oid=pg_index.indrelid
AND indisunique != 't'
AND indisprimary != 't'
);
SELECT t.relname, a.attname, a.attnum
FROM pg_index c
LEFT JOIN pg_class t
ON c.indrelid  = t.oid
LEFT JOIN pg_attribute a
ON a.attrelid = t.oid
AND a.attnum = ANY(indkey)
WHERE t.relname = 'test2'
AND a.attnum = 6; -- this is the index key

列出表的约束

SELECT c.conname AS constraint_name,
CASE c.contype
WHEN 'c' THEN 'CHECK'
WHEN 'f' THEN 'FOREIGN KEY'
WHEN 'p' THEN 'PRIMARY KEY'
WHEN 'u' THEN 'UNIQUE'
END AS "constraint_type",
CASE WHEN c.condeferrable = 'f' THEN 0 ELSE 1 END AS is_deferrable,
CASE WHEN c.condeferred = 'f' THEN 0 ELSE 1 END AS is_deferred,
t.relname AS table_name,
array_to_string(c.conkey, ' ') AS constraint_key,
CASE confupdtype
WHEN 'a' THEN 'NO ACTION'
WHEN 'r' THEN 'RESTRICT'
WHEN 'c' THEN 'CASCADE'
WHEN 'n' THEN 'SET NULL'
WHEN 'd' THEN 'SET DEFAULT'
END AS on_update,
CASE confdeltype
WHEN 'a' THEN 'NO ACTION'
WHEN 'r' THEN 'RESTRICT'
WHEN 'c' THEN 'CASCADE'
WHEN 'n' THEN 'SET NULL'
WHEN 'd' THEN 'SET DEFAULT'
END AS on_delete,
CASE confmatchtype
WHEN 'u' THEN 'UNSPECIFIED'
WHEN 'f' THEN 'FULL'
WHEN 'p' THEN 'PARTIAL'
END AS match_type,
t2.relname AS references_table,
array_to_string(c.confkey, ' ') AS fk_constraint_key
FROM pg_constraint c
LEFT JOIN pg_class t  ON c.conrelid  = t.oid
LEFT JOIN pg_class t2 ON c.confrelid = t2.oid
WHERE t.relname = 'testconstraints2'
AND c.conname = 'testconstraints_id_fk';
-- with INFORMATION_SCHEMA:
SELECT tc.constraint_name,
tc.constraint_type,
tc.table_name,
kcu.column_name,
tc.is_deferrable,
tc.initially_deferred,
rc.match_option AS match_type,
rc.update_rule AS on_update,
rc.delete_rule AS on_delete,
ccu.table_name AS references_table,
ccu.column_name AS references_field
FROM information_schema.table_constraints tc
LEFT JOIN information_schema.key_column_usage kcu
ON tc.constraint_catalog = kcu.constraint_catalog
AND tc.constraint_schema = kcu.constraint_schema
AND tc.constraint_name = kcu.constraint_name
LEFT JOIN information_schema.referential_constraints rc
ON tc.constraint_catalog = rc.constraint_catalog
AND tc.constraint_schema = rc.constraint_schema
AND tc.constraint_name = rc.constraint_name
LEFT JOIN information_schema.constraint_column_usage ccu
ON rc.unique_constraint_catalog = ccu.constraint_catalog
AND rc.unique_constraint_schema = ccu.constraint_schema
AND rc.unique_constraint_name = ccu.constraint_name
WHERE tc.table_name = 'testconstraints2'
AND tc.constraint_name = 'testconstraints_id_fk';


列出所有序列

SELECT relname
FROM pg_class
WHERE relkind = 'S'
AND relnamespace IN (
SELECT oid
FROM pg_namespace
WHERE nspname NOT LIKE 'pg_%'
AND nspname != 'information_schema'
);


列出所有触发器

SELECT trg.tgname AS trigger_name
FROM pg_trigger trg, pg_class tbl
WHERE trg.tgrelid = tbl.oid
AND tbl.relname !~ '^pg_';
-- or
SELECT tgname AS trigger_name
FROM pg_trigger
WHERE tgname !~ '^pg_';
-- with INFORMATION_SCHEMA:
SELECT DISTINCT trigger_name
FROM information_schema.triggers
WHERE trigger_schema NOT IN
('pg_catalog', 'information_schema');
SELECT trg.tgname AS trigger_name
FROM pg_trigger trg, pg_class tbl
WHERE trg.tgrelid = tbl.oid
AND tbl.relname = 'newtable';
-- with INFORMATION_SCHEMA:
SELECT DISTINCT trigger_name
FROM information_schema.triggers
WHERE event_object_table = 'newtable'
AND trigger_schema NOT IN
('pg_catalog', 'information_schema');

列出所有触发器的信息

SELECT trg.tgname AS trigger_name,
tbl.relname AS table_name,
p.proname AS function_name,
CASE trg.tgtype & cast(2 as int2)
WHEN 0 THEN 'AFTER'
ELSE 'BEFORE'
END AS trigger_type,
CASE trg.tgtype & cast(28 as int2)
WHEN 16 THEN 'UPDATE'
WHEN  8 THEN 'DELETE'
WHEN  4 THEN 'INSERT'
WHEN 20 THEN 'INSERT, UPDATE'
WHEN 28 THEN 'INSERT, UPDATE, DELETE'
WHEN 24 THEN 'UPDATE, DELETE'
WHEN 12 THEN 'INSERT, DELETE'
END AS trigger_event,
CASE trg.tgtype & cast(1 as int2)
WHEN 0 THEN 'STATEMENT'
ELSE 'ROW'
END AS action_orientation
FROM pg_trigger trg,
pg_class tbl,
pg_proc p
WHERE trg.tgrelid = tbl.oid
AND trg.tgfoid = p.oid
AND tbl.relname !~ '^pg_';
-- with INFORMATION_SCHEMA:
SELECT *
FROM information_schema.triggers
WHERE trigger_schema NOT IN
('pg_catalog', 'information_schema');


列出所有函数

SELECT proname
FROM pg_proc pr,
pg_type tp
WHERE tp.oid = pr.prorettype
AND pr.proisagg = FALSE
AND tp.typname <> 'trigger'
AND pr.pronamespace IN (
SELECT oid
FROM pg_namespace
WHERE nspname NOT LIKE 'pg_%'
AND nspname != 'information_schema'
);
-- with INFORMATION_SCHEMA:
SELECT routine_name
FROM information_schema.routines
WHERE specific_schema NOT IN
('pg_catalog', 'information_schema')
AND type_udt_name != 'trigger';


Albe Laurenz sent me the following function that is even more informative: for a function name and schema, it selects the position in the argument list, the direction, the name and the data-type of each argument. This procedure requires PostgreSQL 8.1 or later.

CREATE OR REPLACE FUNCTION public.function_args(
IN funcname character varying,
IN schema character varying,
OUT pos integer,
OUT direction character,
OUT argname character varying,
OUT datatype character varying)
RETURNS SETOF RECORD AS $$DECLARE
rettype character varying;
argtypes oidvector;
allargtypes oid[];
argmodes "char"[];
argnames text[];
mini integer;
maxi integer;
BEGIN
/* get object ID of function */
SELECT INTO rettype, argtypes, allargtypes, argmodes, argnames
CASE
WHEN pg_proc.proretset
THEN 'setof ' || pg_catalog.format_type(pg_proc.prorettype, NULL)
ELSE pg_catalog.format_type(pg_proc.prorettype, NULL) END,
pg_proc.proargtypes,
pg_proc.proallargtypes,
pg_proc.proargmodes,
pg_proc.proargnames
FROM pg_catalog.pg_proc
JOIN pg_catalog.pg_namespace
ON (pg_proc.pronamespace = pg_namespace.oid)
WHERE pg_proc.prorettype <> 'pg_catalog.cstring'::pg_catalog.regtype
AND (pg_proc.proargtypes[0] IS NULL
OR pg_proc.proargtypes[0] <> 'pg_catalog.cstring'::pg_catalog.regtype)
AND NOT pg_proc.proisagg
AND pg_proc.proname = funcname
AND pg_namespace.nspname = schema
AND pg_catalog.pg_function_is_visible(pg_proc.oid);
/* bail out if not found */
IF NOT FOUND THEN
RETURN;
END IF;
/* return a row for the return value */
pos = 0;
direction = 'o'::char;
argname = 'RETURN VALUE';
datatype = rettype;
RETURN NEXT;
/* unfortunately allargtypes is NULL if there are no OUT parameters */
IF allargtypes IS NULL THEN
mini = array_lower(argtypes, 1); maxi = array_upper(argtypes, 1);
ELSE
mini = array_lower(allargtypes, 1); maxi = array_upper(allargtypes, 1);
END IF;
IF maxi < mini THEN RETURN; END IF;
/* loop all the arguments */
FOR i IN mini .. maxi LOOP
pos = i - mini + 1;
IF argnames IS NULL THEN
argname = NULL;
ELSE
argname = argnames[pos];
END IF;
IF allargtypes IS NULL THEN
direction = 'i'::char;
datatype = pg_catalog.format_type(argtypes, NULL);
ELSE
direction = argmodes;
datatype = pg_catalog.format_type(allargtypes, NULL);
END IF;
RETURN NEXT;
END LOOP;
RETURN;
END;$$ LANGUAGE plpgsql STABLE STRICT SECURITY INVOKER;
COMMENT ON FUNCTION public.function_args(character varying, character
varying)
IS $$For a function name and schema, this procedure selects for each
argument the following data:
- position in the argument list (0 for the return value)
- direction 'i', 'o', or 'b'
- name (NULL if not defined)
- data type$$;


列出所有存储过程

SELECT p.proname AS procedure_name,
p.pronargs AS num_args,
t1.typname AS return_type,
a.rolname AS procedure_owner,
l.lanname AS language_type,
p.proargtypes AS argument_types_oids,
prosrc AS body
FROM pg_proc p
LEFT JOIN pg_type t1 ON p.prorettype=t1.oid   
LEFT JOIN pg_authid a ON p.proowner=a.oid
LEFT JOIN pg_language l ON p.prolang=l.oid
WHERE proname = :PROCEDURE_NAME;