# engine=innodb
create table product (
category int not null,
id int not null,
price decimal,
primary key(category, id))
engine=innodb;
create table customer (
id int not null,
primary key (id))
engine=innodb;
create table product_order (
no int not null auto_increment,
product_category int not null,
product_id int not null,
customer_id int not null,
primary key(no),
index (product_category, product_id),
constraint fk1 foreign key (product_category, product_id)
references product(category, id)
on update restrict on delete cascade,
index (customer_id),
constraint fk2 foreign key (customer_id) references customer(id))
engine=innodb;
create table emp (
id int primary key auto_increment,
manager int,
key (manager),
constraint emp_fk1 foreign key (manager) references emp (id))
engine=innodb;
select *
from information_schema.table_constraints
where table_schema = 'test'
order by table_name, constraint_type, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_SCHEMA	TABLE_NAME	CONSTRAINT_TYPE	ENFORCED
def	test	PRIMARY	test	customer	PRIMARY KEY	YES
def	test	emp_fk1	test	emp	FOREIGN KEY	YES
def	test	PRIMARY	test	emp	PRIMARY KEY	YES
def	test	PRIMARY	test	product	PRIMARY KEY	YES
def	test	fk1	test	product_order	FOREIGN KEY	YES
def	test	fk2	test	product_order	FOREIGN KEY	YES
def	test	PRIMARY	test	product_order	PRIMARY KEY	YES
COL	ORDINAL_POSITION	POSITION_IN_UNIQUE_CONSTRAINT	REFERENCED_COL
customer.id	1	NULL	
emp.id	1	NULL	
emp.manager	1	1	emp.id
product.category	1	NULL	
product.id	2	NULL	
product_order.customer_id	1	1	customer.id
product_order.no	1	NULL	
product_order.product_category	1	1	product.category
product_order.product_id	2	2	product.id
drop table product_order, customer, product, emp;
create database mydb1;
create database mydb2;
create table mydb1.t1 (
a1 int not null,
b1 int not null,
primary key using hash (a1),
unique key xb1 (b1)
) engine=innodb;
Warnings:
Note	3502	This storage engine does not support the HASH index algorithm, storage engine default was used instead.
create table mydb2.t2 (
a2 int not null,
b2 int not null,
primary key using hash (a2),
unique key xb2 (b2)
) engine=innodb;
Warnings:
Note	3502	This storage engine does not support the HASH index algorithm, storage engine default was used instead.
alter table mydb1.t1
add constraint fk_b1a1 foreign key (b1) references mydb1.t1 (a1),
add constraint fk_b1b2 foreign key (b1) references mydb2.t2 (b2);
alter table mydb2.t2
add constraint fk_b2a2 foreign key (b2) references mydb2.t2 (a2),
add constraint fk_b2b1 foreign key (b2) references mydb1.t1 (b1);
select *
from information_schema.referential_constraints
order by constraint_schema, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	UNIQUE_CONSTRAINT_CATALOG	UNIQUE_CONSTRAINT_SCHEMA	UNIQUE_CONSTRAINT_NAME	MATCH_OPTION	UPDATE_RULE	DELETE_RULE	TABLE_NAME	REFERENCED_TABLE_NAME
def	mydb1	fk_b1a1	def	mydb1	PRIMARY	NONE	NO ACTION	NO ACTION	t1	t1
def	mydb1	fk_b1b2	def	mydb2	xb2	NONE	NO ACTION	NO ACTION	t1	t2
def	mydb2	fk_b2a2	def	mydb2	PRIMARY	NONE	NO ACTION	NO ACTION	t2	t2
def	mydb2	fk_b2b1	def	mydb1	xb1	NONE	NO ACTION	NO ACTION	t2	t1
select *
from information_schema.table_constraints
where table_schema like 'mydb%'
order by table_name, constraint_type, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_SCHEMA	TABLE_NAME	CONSTRAINT_TYPE	ENFORCED
def	mydb1	fk_b1a1	mydb1	t1	FOREIGN KEY	YES
def	mydb1	fk_b1b2	mydb1	t1	FOREIGN KEY	YES
def	mydb1	PRIMARY	mydb1	t1	PRIMARY KEY	YES
def	mydb1	xb1	mydb1	t1	UNIQUE	YES
def	mydb2	fk_b2a2	mydb2	t2	FOREIGN KEY	YES
def	mydb2	fk_b2b1	mydb2	t2	FOREIGN KEY	YES
def	mydb2	PRIMARY	mydb2	t2	PRIMARY KEY	YES
def	mydb2	xb2	mydb2	t2	UNIQUE	YES
select *
from information_schema.key_column_usage
where table_schema like 'mydb%'
order by constraint_schema, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	COLUMN_NAME	ORDINAL_POSITION	POSITION_IN_UNIQUE_CONSTRAINT	REFERENCED_TABLE_SCHEMA	REFERENCED_TABLE_NAME	REFERENCED_COLUMN_NAME
def	mydb1	fk_b1a1	def	mydb1	t1	b1	1	1	mydb1	t1	a1
def	mydb1	fk_b1b2	def	mydb1	t1	b1	1	1	mydb2	t2	b2
def	mydb1	PRIMARY	def	mydb1	t1	a1	1	NULL	NULL	NULL	NULL
def	mydb1	xb1	def	mydb1	t1	b1	1	NULL	NULL	NULL	NULL
def	mydb2	fk_b2a2	def	mydb2	t2	b2	1	1	mydb2	t2	a2
def	mydb2	fk_b2b1	def	mydb2	t2	b2	1	1	mydb1	t1	b1
def	mydb2	PRIMARY	def	mydb2	t2	a2	1	NULL	NULL	NULL	NULL
def	mydb2	xb2	def	mydb2	t2	b2	1	NULL	NULL	NULL	NULL
alter table mydb1.t1
drop foreign key fk_b1a1,
drop foreign key fk_b1b2;
alter table mydb2.t2
drop foreign key fk_b2a2,
drop foreign key fk_b2b1;
drop table mydb1.t1;
drop table mydb2.t2;
drop database mydb1;
drop database mydb2;
# engine=ndb
create table product (
category int not null,
id int not null,
price decimal,
primary key(category, id))
engine=ndb;
create table customer (
id int not null,
primary key (id))
engine=ndb;
create table product_order (
no int not null auto_increment,
product_category int not null,
product_id int not null,
customer_id int not null,
primary key(no),
index (product_category, product_id),
constraint fk1 foreign key (product_category, product_id)
references product(category, id)
on update restrict on delete cascade,
index (customer_id),
constraint fk2 foreign key (customer_id) references customer(id))
engine=ndb;
create table emp (
id int primary key auto_increment,
manager int,
key (manager),
constraint emp_fk1 foreign key (manager) references emp (id))
engine=ndb;
select *
from information_schema.table_constraints
where table_schema = 'test'
order by table_name, constraint_type, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_SCHEMA	TABLE_NAME	CONSTRAINT_TYPE	ENFORCED
def	test	PRIMARY	test	customer	PRIMARY KEY	YES
def	test	emp_fk1	test	emp	FOREIGN KEY	YES
def	test	PRIMARY	test	emp	PRIMARY KEY	YES
def	test	PRIMARY	test	product	PRIMARY KEY	YES
def	test	fk1	test	product_order	FOREIGN KEY	YES
def	test	fk2	test	product_order	FOREIGN KEY	YES
def	test	PRIMARY	test	product_order	PRIMARY KEY	YES
COL	ORDINAL_POSITION	POSITION_IN_UNIQUE_CONSTRAINT	REFERENCED_COL
customer.id	1	NULL	
emp.id	1	NULL	
emp.manager	1	1	emp.id
product.category	1	NULL	
product.id	2	NULL	
product_order.customer_id	1	1	customer.id
product_order.no	1	NULL	
product_order.product_category	1	1	product.category
product_order.product_id	2	2	product.id
drop table product_order, customer, product, emp;
create database mydb1;
create database mydb2;
create table mydb1.t1 (
a1 int not null,
b1 int not null,
primary key using hash (a1),
unique key xb1 (b1)
) engine=ndb;
create table mydb2.t2 (
a2 int not null,
b2 int not null,
primary key using hash (a2),
unique key xb2 (b2)
) engine=ndb;
alter table mydb1.t1
add constraint fk_b1a1 foreign key (b1) references mydb1.t1 (a1),
add constraint fk_b1b2 foreign key (b1) references mydb2.t2 (b2);
alter table mydb2.t2
add constraint fk_b2a2 foreign key (b2) references mydb2.t2 (a2),
add constraint fk_b2b1 foreign key (b2) references mydb1.t1 (b1);
select *
from information_schema.referential_constraints
order by constraint_schema, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	UNIQUE_CONSTRAINT_CATALOG	UNIQUE_CONSTRAINT_SCHEMA	UNIQUE_CONSTRAINT_NAME	MATCH_OPTION	UPDATE_RULE	DELETE_RULE	TABLE_NAME	REFERENCED_TABLE_NAME
def	mydb1	fk_b1a1	def	mydb1	PRIMARY	NONE	NO ACTION	NO ACTION	t1	t1
def	mydb1	fk_b1b2	def	mydb2	xb2	NONE	NO ACTION	NO ACTION	t1	t2
def	mydb2	fk_b2a2	def	mydb2	PRIMARY	NONE	NO ACTION	NO ACTION	t2	t2
def	mydb2	fk_b2b1	def	mydb1	xb1	NONE	NO ACTION	NO ACTION	t2	t1
select *
from information_schema.table_constraints
where table_schema like 'mydb%'
order by table_name, constraint_type, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_SCHEMA	TABLE_NAME	CONSTRAINT_TYPE	ENFORCED
def	mydb1	fk_b1a1	mydb1	t1	FOREIGN KEY	YES
def	mydb1	fk_b1b2	mydb1	t1	FOREIGN KEY	YES
def	mydb1	PRIMARY	mydb1	t1	PRIMARY KEY	YES
def	mydb1	xb1	mydb1	t1	UNIQUE	YES
def	mydb2	fk_b2a2	mydb2	t2	FOREIGN KEY	YES
def	mydb2	fk_b2b1	mydb2	t2	FOREIGN KEY	YES
def	mydb2	PRIMARY	mydb2	t2	PRIMARY KEY	YES
def	mydb2	xb2	mydb2	t2	UNIQUE	YES
select *
from information_schema.key_column_usage
where table_schema like 'mydb%'
order by constraint_schema, constraint_name;
CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	COLUMN_NAME	ORDINAL_POSITION	POSITION_IN_UNIQUE_CONSTRAINT	REFERENCED_TABLE_SCHEMA	REFERENCED_TABLE_NAME	REFERENCED_COLUMN_NAME
def	mydb1	fk_b1a1	def	mydb1	t1	b1	1	1	mydb1	t1	a1
def	mydb1	fk_b1b2	def	mydb1	t1	b1	1	1	mydb2	t2	b2
def	mydb1	PRIMARY	def	mydb1	t1	a1	1	NULL	NULL	NULL	NULL
def	mydb1	xb1	def	mydb1	t1	b1	1	NULL	NULL	NULL	NULL
def	mydb2	fk_b2a2	def	mydb2	t2	b2	1	1	mydb2	t2	a2
def	mydb2	fk_b2b1	def	mydb2	t2	b2	1	1	mydb1	t1	b1
def	mydb2	PRIMARY	def	mydb2	t2	a2	1	NULL	NULL	NULL	NULL
def	mydb2	xb2	def	mydb2	t2	b2	1	NULL	NULL	NULL	NULL
alter table mydb1.t1
drop foreign key fk_b1a1,
drop foreign key fk_b1b2;
alter table mydb2.t2
drop foreign key fk_b2a2,
drop foreign key fk_b2b1;
drop table mydb1.t1;
drop table mydb2.t2;
drop database mydb1;
drop database mydb2;