Added foreign_key table constraint

include/sqlite3.hrl

@@ -31,7 +31,7 @@
 -type column_constraint() :: non_null | primary_key | {primary_key, pk_constraints()}
                              | unique | {default, sql_value()}.
 -type column_constraints() :: column_constraint() | [column_constraint()].
--type table_constraint() :: {primary_key, [atom()]} | {unique, [atom()]}.
+-type table_constraint() :: {primary_key, [atom()]} | {foreign_key, {[atom()], atom(), [atom()]}} | {unique, [atom()]}.
 -type table_constraints() :: table_constraint() | [table_constraint()].
 -type table_info() :: [{column_id(), sql_type()} | {column_id(), sql_type(), column_constraints()}].
 

src/sqlite3_lib.erl

@@ -376,7 +376,14 @@ table_constraint_sql(TableConstraint) ->
         {unique, Columns} ->
             ["UNIQUE(",
              map_intersperse(fun indexed_column_sql/1, Columns, ", "), ")"];
-        %% TODO: foreign key
+        {foreign_key, {Columns, Parent, ParentColumns}} ->
+            ["FOREIGN KEY(",
+             map_intersperse(fun indexed_column_sql/1, Columns, ", "),
+             ") REFERENCES ",
+             atom_to_list(Parent),
+             "(",
+             map_intersperse(fun indexed_column_sql/1, ParentColumns, ", "),
+             ")"];
         {raw, S} when is_list(S) -> S;
         _ when is_list(TableConstraint) ->
             map_intersperse(fun table_constraint_sql/1, TableConstraint, ", ")