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
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');
扩展到ollyc配方:
CREATE VIEW foreign_keys_view AS
SELECT
tc.table_name, kcu.column_name,
ccu.table_name AS foreign_table_name,
ccu.column_name AS foreign_column_name
FROM
information_schema.table_constraints AS tc
JOIN information_schema.key_column_usage
AS kcu ON tc.constraint_name = kcu.constraint_name
JOIN information_schema.constraint_column_usage
AS ccu ON ccu.constraint_name = tc.constraint_name
WHERE constraint_type = 'FOREIGN KEY';
然后:
SELECT * FROM foreign_keys_view WHERE table_name='YourTableNameHere';
$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;
我认为你想要的和@ollyc写的很接近的是:
SELECT
tc.constraint_name, tc.table_name, kcu.column_name,
ccu.table_name AS foreign_table_name,
ccu.column_name AS foreign_column_name
FROM
information_schema.table_constraints AS tc
JOIN information_schema.key_column_usage AS kcu
ON tc.constraint_name = kcu.constraint_name
JOIN information_schema.constraint_column_usage AS ccu
ON ccu.constraint_name = tc.constraint_name
WHERE constraint_type = 'FOREIGN KEY' AND ccu.table_name='YourTableNameHere';
这将列出所有使用指定表作为外键的表
选择的答案不为我工作,所以张贴我的sql工作。
select
con.conname as constraint_name,
src_schema.nspname as source_schema,
source.relname as source_table,
source_col.attname as source_column,
trg_schema.nspname as target_schema,
target.relname as target_table,
target_col.attname as target_column
from
pg_constraint con
inner join
pg_class source on source.oid = con.conrelid
inner join
pg_attribute source_col on source_col.attrelid = con.conrelid and source_col.attnum = con.conkey[1] and source_col.attisdropped = false
inner join
pg_namespace src_schema on src_schema.oid = source.relnamespace
inner join
pg_class target on target.oid = con.confrelid
inner join
pg_attribute target_col on target_col.attrelid = con.confrelid and target_col.attnum = con.confkey[1] and source_col.attisdropped = false
inner join
pg_namespace trg_schema on trg_schema.oid = target.relnamespace
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