是否有一种方法使用SQL列出给定表的所有外键?我知道表名/模式,我可以把它插入。
当前回答
$1 ('my_schema')是模式,$2 ('my_table')是表名:
SELECT ss.conname constraint_name, a.attname column_name, ss.refnamespace fk_table_schema, ss.reflname fk_table_name, af.attname fk_column_name
FROM pg_attribute a, pg_attribute af,
(SELECT r.oid roid, c.conname, rf.relname reflname, information_schema._pg_expandarray(c.conkey) x,
nrf.nspname refnamespace, rf.oid rfoid, information_schema._pg_expandarray(cf.confkey) xf
FROM pg_namespace nr, pg_class r, pg_constraint c,
pg_namespace nrf, pg_class rf, pg_constraint cf
WHERE nr.oid = r.relnamespace
AND r.oid = c.conrelid
AND rf.oid = cf.confrelid
AND c.conname = cf.conname
AND nrf.oid = rf.relnamespace
AND nr.nspname = $1
AND r.relname = $2) ss
WHERE ss.roid = a.attrelid AND a.attnum = (ss.x).x AND NOT a.attisdropped
AND ss.rfoid = af.attrelid AND af.attnum = (ss.xf).x AND NOT af.attisdropped
ORDER BY ss.conname, a.attname;
其他回答
这个查询也适用于组合键:
select c.constraint_name
, x.table_schema as schema_name
, x.table_name
, x.column_name
, y.table_schema as foreign_schema_name
, y.table_name as foreign_table_name
, y.column_name as foreign_column_name
from information_schema.referential_constraints c
join information_schema.key_column_usage x
on x.constraint_name = c.constraint_name
join information_schema.key_column_usage y
on y.ordinal_position = x.position_in_unique_constraint
and y.constraint_name = c.unique_constraint_name
order by c.constraint_name, x.ordinal_position
在PostgreSQL提示符上发出\d+ tablename,除了显示表列的数据类型外,它还会显示索引和外键。
检查ff帖子的解决方案,不要忘记标记这个,当你认为这是有帮助的
http://errorbank.blogspot.com/2011/03/list-all-foreign-keys-references-for.html
SELECT
o.conname AS constraint_name,
(SELECT nspname FROM pg_namespace WHERE oid=m.relnamespace) AS source_schema,
m.relname AS source_table,
(SELECT a.attname FROM pg_attribute a WHERE a.attrelid = m.oid AND a.attnum = o.conkey[1] AND a.attisdropped = false) AS source_column,
(SELECT nspname FROM pg_namespace WHERE oid=f.relnamespace) AS target_schema,
f.relname AS target_table,
(SELECT a.attname FROM pg_attribute a WHERE a.attrelid = f.oid AND a.attnum = o.confkey[1] AND a.attisdropped = false) AS target_column
FROM
pg_constraint o LEFT JOIN pg_class f ON f.oid = o.confrelid LEFT JOIN pg_class m ON m.oid = o.conrelid
WHERE
o.contype = 'f' AND o.conrelid IN (SELECT oid FROM pg_class c WHERE c.relkind = 'r');
这是我目前使用的,它将列出一个表,它的fkey约束[删除表子句,它将列出当前目录中的所有表]:
SELECT
current_schema() AS "schema",
current_catalog AS "database",
"pg_constraint".conrelid::regclass::text AS "primary_table_name",
"pg_constraint".confrelid::regclass::text AS "foreign_table_name",
(
string_to_array(
(
string_to_array(
pg_get_constraintdef("pg_constraint".oid),
'('
)
)[2],
')'
)
)[1] AS "foreign_column_name",
"pg_constraint".conindid::regclass::text AS "constraint_name",
TRIM((
string_to_array(
pg_get_constraintdef("pg_constraint".oid),
'('
)
)[1]) AS "constraint_type",
pg_get_constraintdef("pg_constraint".oid) AS "constraint_definition"
FROM pg_constraint AS "pg_constraint"
JOIN pg_namespace AS "pg_namespace" ON "pg_namespace".oid = "pg_constraint".connamespace
WHERE
--fkey and pkey constraints
"pg_constraint".contype IN ( 'f', 'p' )
AND
"pg_namespace".nspname = current_schema()
AND
"pg_constraint".conrelid::regclass::text IN ('whatever_table_name')
SELECT conrelid::regclass AS table_name,
conname AS foreign_key,
pg_get_constraintdef(oid)
FROM pg_constraint
WHERE contype = 'f'
AND connamespace = 'public'::regnamespace
ORDER BY conrelid::regclass::text, contype DESC;
https://soft-builder.com/how-to-list-all-foreign-keys-in-postgresql-database
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