referential_constraints

The view information_schema.referential_constraints contains all referential constraints (aka foreign keys) in the database.

SELECT * FROM information_schema.referential_constraints;
SELECT constraint_schema, constraint_name, fk_table_name, uc_table_name
 FROM information_schema.referential_constraints;

information_schema.referential_constraints

column nametyperemarks
constraint_catalogVARCHARAlways NULL
constraint_schemaVARCHAR
constraint_nameVARCHAR
unique_constraint_catalogVARCHARAlways NULL
unique_constraint_schemaVARCHAR
unique_constraint_nameVARCHAR
match_optionVARCHARFULL or PARTIAL or NONE, currently always FULL
update_ruleVARCHARCASCADE or RESTRICT or SET DEFAULT or SET NULL or NO ACTION
delete_ruleVARCHARCASCADE or RESTRICT or SET DEFAULT or SET NULL or NO ACTION
fk_schema_idINTEGERreference to sys.schemas.id
fk_table_idINTEGERreference to sys.tables.id
fk_table_nameVARCHARname of table which contains the foreign key
fk_key_idINTEGERreference to sys.fkeys.id
uc_schema_idINTEGERreference to sys.schemas.id
uc_table_idINTEGERreference to sys.tables.id
uc_table_nameVARCHARname of table referenced by the foreign key
uc_key_idINTEGERreference to sys.keys.id

Note: The last 8 columns (fk_schema_id, fk_table_id, fk_table_name, fk_key_id, uc_schema_id, uc_table_id, uc_table_name and uc_key_id) are extensions to the view as defined by ISO standard. They provide useful information and simplify filtering and joins with system tables/views in sys schema when needed.