现有的答案都没有给出我想要的结果。这是我的(庞大的)查询，用于查找有关外键的信息。

注意事项:

The expressions used to generate from_cols and to_cols could be vastly simplified on Postgres 9.4 and later using WITH ORDINALITY rather than the window-function-using hackery I'm using. Those same expressions are relying on the query planner not altering the returned order of results from UNNEST. I don't think it will, but I don't have any multiple-column foreign keys in my dataset to test with. Adding the 9.4 niceties eliminates this possibility altogether. The query itself requires Postgres 9.0 or later (8.x didn't allow ORDER BY in aggregate functions) Replace STRING_AGG with ARRAY_AGG if you want an array of columns rather than a comma-separated string.

-

SELECT
    c.conname AS constraint_name,
    (SELECT n.nspname FROM pg_namespace AS n WHERE n.oid=c.connamespace) AS constraint_schema,

    tf.name AS from_table,
    (
        SELECT STRING_AGG(QUOTE_IDENT(a.attname), ', ' ORDER BY t.seq)
        FROM
            (
                SELECT
                    ROW_NUMBER() OVER (ROWS UNBOUNDED PRECEDING) AS seq,
                    attnum
                FROM
                    UNNEST(c.conkey) AS t(attnum)
            ) AS t
            INNER JOIN pg_attribute AS a ON a.attrelid=c.conrelid AND a.attnum=t.attnum
    ) AS from_cols,

    tt.name AS to_table,
    (
        SELECT STRING_AGG(QUOTE_IDENT(a.attname), ', ' ORDER BY t.seq)
        FROM
            (
                SELECT
                    ROW_NUMBER() OVER (ROWS UNBOUNDED PRECEDING) AS seq,
                    attnum
                FROM
                    UNNEST(c.confkey) AS t(attnum)
            ) AS t
            INNER JOIN pg_attribute AS a ON a.attrelid=c.confrelid AND a.attnum=t.attnum
    ) AS to_cols,

    CASE confupdtype WHEN 'r' THEN 'restrict' WHEN 'c' THEN 'cascade' WHEN 'n' THEN 'set null' WHEN 'd' THEN 'set default' WHEN 'a' THEN 'no action' ELSE NULL END AS on_update,
    CASE confdeltype WHEN 'r' THEN 'restrict' WHEN 'c' THEN 'cascade' WHEN 'n' THEN 'set null' WHEN 'd' THEN 'set default' WHEN 'a' THEN 'no action' ELSE NULL END AS on_delete,
    CASE confmatchtype::text WHEN 'f' THEN 'full' WHEN 'p' THEN 'partial' WHEN 'u' THEN 'simple' WHEN 's' THEN 'simple' ELSE NULL END AS match_type,  -- In earlier postgres docs, simple was 'u'nspecified, but current versions use 's'imple.  text cast is required.

    pg_catalog.pg_get_constraintdef(c.oid, true) as condef
FROM
    pg_catalog.pg_constraint AS c
    INNER JOIN (
        SELECT pg_class.oid, QUOTE_IDENT(pg_namespace.nspname) || '.' || QUOTE_IDENT(pg_class.relname) AS name
        FROM pg_class INNER JOIN pg_namespace ON pg_class.relnamespace=pg_namespace.oid
    ) AS tf ON tf.oid=c.conrelid
    INNER JOIN (
        SELECT pg_class.oid, QUOTE_IDENT(pg_namespace.nspname) || '.' || QUOTE_IDENT(pg_class.relname) AS name
        FROM pg_class INNER JOIN pg_namespace ON pg_class.relnamespace=pg_namespace.oid
    ) AS tt ON tt.oid=c.confrelid
WHERE c.contype = 'f' ORDER BY 1;

使用Key所引用的主键的名称并查询information_schema:

select table_name, column_name
from information_schema.key_column_usage
where constraint_name IN (select constraint_name
  from information_schema.referential_constraints 
  where unique_constraint_name = 'TABLE_NAME_pkey')

这里'TABLE_NAME_pkey'是外键引用的主键的名称。

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');

你可以使用PostgreSQL系统目录。也许您可以查询pg_constraint来请求外键。 您还可以使用信息模式

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_from,
    conname,
    pg_get_constraintdef(oid) as condef    
    FROM pg_catalog.pg_constraint r

也适用于所有约束条件。例如，使用pysql: