information_schema.check_constraints Inconsistencies

Hello,

I am writing with regards to some wrong results I keep on receiving when
using check_constraints view from information_schema:

(1) First, it shows constraints grouped by name, regardless of the relation
used: when having two constraints with the same name in different tables,
it shows both in both tables, regardless of their belonging;
(2) Second, it also lists NOT NULL constraints, even though they are not
created as check constraints.

See, for example, the following select:
select *
from information_schema.table_constraints c
join information_schema.check_constraints ck
on c.constraint_name = ck.constraint_name
and c.constraint_schema = ck.constraint_schema
and c.constraint_catalog = ck.constraint_catalog
where c.constraint_type = 'CHECK'
and c.table_schema = 'events'
and c.table_name = 'horse_racing_purchase_event'
It returns data in --PASTE1-- (at end).

Postgresql version used:
PostgreSQL 10.3, compiled by Visual C++ build 1800, 64-bit

Data used:
create schema events;

create table if not exists events.event
(
id bigserial not null
constraint event_pkey
primary key,
occurred_at timestamp default CURRENT_TIMESTAMP not null,
operator_id integer not null,
player_id integer not null,
player_ip inet not null,
session_id uuid not null,
has_player_confirmation boolean default true not null,
transformed_event text,
arjel_type_id smallint
)
;

create table if not exists events.horse_racing_purchase_event
(
purchase_id bigint not null,
event_label_as_shown_to_player text not null
constraint c_event_label_as_shown_to_player
check (public.is_valid_string(256,
event_label_as_shown_to_player)),
balance_before money,
balance_after money,
bet_amount money,
bet_contribution_from_operator money,
bonus_before money,
bonus_after money,
bonus_amount money,
bonus_name text,
race_type text not null
constraint c_race_type
check (public.is_valid_string(64, race_type)),
bet_name_as_shown_to_player text not null
constraint c_bet_name_as_shown_to_player
check (public.is_valid_string(64, bet_name_as_shown_to_player)),
event_date timestamp not null,
constraint horse_racing_purchase_event_pkey
primary key (id),
constraint c_balance
check ((((balance_before + balance_after) + bet_amount) IS NOT
NULL) OR (COALESCE(balance_before, balance_after, bet_amount) IS NULL)),
constraint c_bonus
check ((((bonus_before + bonus_after) + bonus_amount) IS NOT NULL)
OR (COALESCE(bonus_before, bonus_after, bonus_amount) IS NULL))
)
inherits (events.event)
;

comment on column events.horse_racing_purchase_event.bet_amount is 'without
operator contribution and bonuses'
;

create table if not exists events.balance_adjustment_event
(
account_type_id smallint not null
constraint balance_adjustment_event_account_type_id_fkey
references agreement_type,
information_text text not null,
adjustment_type_id smallint not null
constraint balance_adjustment_event_adjustment_type_id_fkey
references adjustment_type,
balance_before numeric(21,4),
balance_after numeric(21,4),
adjustment_to_balance_amount numeric(21,4),
bonus_before numeric(21,4),
bonus_after numeric(21,4),
adjustment_to_bonus_amount numeric(21,4),
constraint balance_adjustment_event_pkey
primary key (id),
constraint c_bonus
check ((((adjustment_to_bonus_amount + bonus_before) + bonus_after)
IS NOT NULL) OR (COALESCE(adjustment_to_bonus_amount, bonus_before,
bonus_after) IS NULL)),
constraint c_balance
check ((((adjustment_to_balance_amount + balance_before) +
balance_after) IS NOT NULL) OR (COALESCE(adjustment_to_balance_amount,
balance_before, balance_after) IS NULL))
)
inherits (events.event)
;

--PASTE1--
i_r_french_regulation events c_balance i_r_french_regulation
events horse_racing_purchase_event CHECK NO NO
i_r_french_regulation events c_balance (((((balance_before +
balance_after) + bet_amount) IS NOT NULL) OR (COALESCE(balance_before,
balance_after, bet_amount) IS NULL)))
i_r_french_regulation events c_balance i_r_french_regulation
events horse_racing_purchase_event CHECK NO NO
i_r_french_regulation events c_balance
(((((adjustment_to_balance_amount + balance_before) + balance_after) IS NOT
NULL) OR (COALESCE(adjustment_to_balance_amount, balance_before,
balance_after) IS NULL)))
i_r_french_regulation events c_bet_name_as_shown_to_player
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events
c_bet_name_as_shown_to_player (is_valid_string(64,
bet_name_as_shown_to_player))
i_r_french_regulation events c_bonus i_r_french_regulation
events horse_racing_purchase_event CHECK NO NO
i_r_french_regulation events c_bonus
(((((adjustment_to_bonus_amount + bonus_before) + bonus_after) IS NOT NULL)
OR (COALESCE(adjustment_to_bonus_amount, bonus_before, bonus_after) IS
NULL)))
i_r_french_regulation events c_bonus i_r_french_regulation
events horse_racing_purchase_event CHECK NO NO
i_r_french_regulation events c_bonus (((((bonus_before +
bonus_after) + bonus_amount) IS NOT NULL) OR (COALESCE(bonus_before,
bonus_after, bonus_amount) IS NULL)))
i_r_french_regulation events c_event_label_as_shown_to_player
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events
c_event_label_as_shown_to_player (is_valid_string(256,
event_label_as_shown_to_player))
i_r_french_regulation events c_event_label_as_shown_to_player
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events
c_event_label_as_shown_to_player (((event_label_as_shown_to_player IS
NULL) OR is_valid_string(256, event_label_as_shown_to_player)))
i_r_french_regulation events c_race_type i_r_french_regulation
events horse_racing_purchase_event CHECK NO NO
i_r_french_regulation events c_race_type (is_valid_string(64,
race_type))
i_r_french_regulation events 16395_16531_1_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_1_not_null id
IS NOT NULL
i_r_french_regulation events 16395_16531_2_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_2_not_null
occurred_at IS NOT NULL
i_r_french_regulation events 16395_16531_3_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_3_not_null
operator_id IS NOT NULL
i_r_french_regulation events 16395_16531_4_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_4_not_null
player_id IS NOT NULL
i_r_french_regulation events 16395_16531_5_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_5_not_null
player_ip IS NOT NULL
i_r_french_regulation events 16395_16531_6_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_6_not_null
session_id IS NOT NULL
i_r_french_regulation events 16395_16531_7_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_7_not_null
has_player_confirmation IS NOT NULL
i_r_french_regulation events 16395_16531_8_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_8_not_null
purchase_id IS NOT NULL
i_r_french_regulation events 16395_16531_9_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_9_not_null
event_label_as_shown_to_player IS NOT NULL
i_r_french_regulation events 16395_16531_18_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_18_not_null
race_type IS NOT NULL
i_r_french_regulation events 16395_16531_19_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_19_not_null
bet_name_as_shown_to_player IS NOT NULL
i_r_french_regulation events 16395_16531_20_not_null
i_r_french_regulation events horse_racing_purchase_event CHECK
NO NO i_r_french_regulation events 16395_16531_20_not_null
event_date IS NOT NULL

Best regards,
Hristo Ivanov