SQLite list ALL foreign keys in a database - sqlite

Question

Is there a way of listing ALL foreign keys in a SQLite database?
They don't seem to be stored in sqlite_master and PRAGMA foreign_key_list('table') only lists one at a time.
Alternatively, is there a way of listing what foreign keys reference a table?

Answer 1

It seems that all (or many) of the PRAGMA commands can be programatically selected with a little trick;
Usually the are called like:
PRAGMA table_info('my_table');
PRAGMA foreign_key_list('my_table');
But this can also be done:
SELECT * FROM pragma_table_info('my_table');
SELECT * FROM pragma_foreign_key_list('my_table');
And the schema can also be (more or less) obtained:
.schema pragma_table_info
/* pragma_table_info(cid,name,type,"notnull",dflt_value,pk) */;
.schema pragma_foreign_key_list
/* pragma_foreign_key_list(id,seq,"table","from","to",on_update,on_delete,"match") */
So, to get all the fks a JOIN between sqlite_master and pragma_foreign_key_list can do the trick:
SELECT
m.name
, p.*
FROM
sqlite_master m
JOIN pragma_foreign_key_list(m.name) p ON m.name != p."table"
WHERE m.type = 'table'
ORDER BY m.name
;
Just take care, that some fields of pragma_foreign_key_list like table, from, ... must be quoted;

Answer 2

With the SQLite shell, use the .schema instruction, and use GREP to filter lines containing REFERENCES.
From shell.c in the SQLite repository, today's version in the trunk, two queries:
SELECT sql
FROM (
SELECT sql sql, type type, tbl_name tbl_name, name name
FROM sqlite_master
UNION ALL
SELECT sql, type, tbl_name, name
FROM sqlite_temp_master
)
WHERE tbl_name LIKE shellstatic()
AND type != 'meta'
AND sql NOTNULL
ORDER BY substr(type, 2, 1), name
and
SELECT sql
FROM (
SELECT sql sql, type type, tbl_name tbl_name, name name
FROM sqlite_master
UNION ALL
SELECT sql, type, tbl_name, name
FROM sqlite_temp_master
)
WHERE type != 'meta'
AND sql NOTNULL
AND name NOT LIKE 'sqlite_%'
ORDER BY substr(type, 2, 1), name
The second one is probably what you are looking for.