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
最快的验证直接在bash答案完全基于这个答案
IFS='' read -r -d '' sql_code << EOF_SQL_CODE
SELECT
o.oid
, 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
, ROW_NUMBER () OVER (ORDER BY o.oid) as rowid
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 1=1
AND o.contype = 'f'
AND o.conrelid IN (SELECT oid FROM pg_class c WHERE c.relkind = 'r')
EOF_SQL_CODE
psql -d my_db -c "$sql_code"
其他回答
从最流行的答案改进查询
因为对于postgresql 12+ information_schema是非常慢的
它帮助了我:
SELECT sh.nspname AS table_schema,
tbl.relname AS table_name,
col.attname AS column_name,
referenced_sh.nspname AS foreign_table_schema,
referenced_tbl.relname AS foreign_table_name,
referenced_field.attname AS foreign_column_name
FROM pg_constraint c
INNER JOIN pg_namespace AS sh ON sh.oid = c.connamespace
INNER JOIN (SELECT oid, unnest(conkey) as conkey FROM pg_constraint) con ON c.oid = con.oid
INNER JOIN pg_class tbl ON tbl.oid = c.conrelid
INNER JOIN pg_attribute col ON (col.attrelid = tbl.oid AND col.attnum = con.conkey)
INNER JOIN pg_class referenced_tbl ON c.confrelid = referenced_tbl.oid
INNER JOIN pg_namespace AS referenced_sh ON referenced_sh.oid = referenced_tbl.relnamespace
INNER JOIN (SELECT oid, unnest(confkey) as confkey FROM pg_constraint) conf ON c.oid = conf.oid
INNER JOIN pg_attribute referenced_field ON (referenced_field.attrelid = c.confrelid AND referenced_field.attnum = conf.confkey)
WHERE c.contype = 'f'
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';
您可以通过information_schema表来实现这一点。例如:
SELECT
tc.table_schema,
tc.constraint_name,
tc.table_name,
kcu.column_name,
ccu.table_schema AS foreign_table_schema,
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
AND tc.table_schema = kcu.table_schema
JOIN information_schema.constraint_column_usage AS ccu
ON ccu.constraint_name = tc.constraint_name
AND ccu.table_schema = tc.table_schema
WHERE tc.constraint_type = 'FOREIGN KEY' AND tc.table_name='mytable';
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
只需替换'您的表名'在下面的查询与您的表名。
简短但贴心的赞,如果对你有用的话。
select * from information_schema.key_column_usage
where constraint_catalog=current_catalog and table_name='your_table_name'
and position_in_unique_constraint notnull;
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