How do i get information about foreign keys in SQLite?

Question

The sqlite_master table seems to lack information. How can i get some extra information about my tables like constraint information etc. Any examples? Or is there some usefull library out there that i`ve never heard off?

Answer 1

Use

PRAGMA foreign_key_list(table);

which returns the foreign keys for a table.

Then, you can use

PRAGMA foreign_key_check; 
PRAGMA foreign_key_check(table);

to list the violations, instead of doing it yourself.

Answer 2

The sql column of sqlite_master contains the SQL used to create tables and thus includes foreign key information.

SELECT tbl_name,sql FROM sqlite_master WHERE sql LIKE('%REFERENCES%')

Would locate the rows for tables with foreign keys.

• REFERENCES , rather than FOREIGN , will include FOREIGN KEY s defined at the column level (as column-constraints), which only uses the foreign-key clause and as such does not include FOREIGN KEY .

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However, PRAGMA foreign_key_list(????) , where ???? is the name of the table to inspect, provides the information in a more usable format (as per example below).

eg extracting from sqlite_master could result in (line breaks added) :-

CREATE TABLE Match(id_Match INTEGER PRIMARY KEY AUTOINCREMENT, 
    id_Court INTEGER REFERENCES Court(id_Court), 
    id_Player INTEGER REFERENCES Player(id_Player), 
    id_Player1 INTEGER REFERENCES Player(id_Player))

whilst using PRAGMA foreign_key_list(Match) results in :-