s0eCMM2a

1create table if not exists messages(
2    id serial primary key, 
3    max_length smallint not null check (max_length > 0),
4    default_text text check (length(default_text) <= max_length),
5    created_on timestamp with time zone not null
6);
7
8create table if not exists customized_messages(
9    message_id serial references messages(id) not null,
10    message text not null, 
11    created_on timestamp with time zone not null
12);
13	
14postgres=# create table if not exists messages(
15postgres(#     id serial primary key, 
16postgres(#     max_length smallint not null check (max_length > 0),
17postgres(#     default_text text check (length(default_text) <= max_length),
18postgres(#     created_on timestamp with time zone not null
19postgres(# );
20CREATE TABLE
21postgres=# 
22postgres=# create table if not exists customized_messages(
23postgres(#     message_id serial references messages(id) not null,
24postgres(#     message text not null, 
25postgres(#     created_on timestamp with time zone not null
26postgres(# );
27CREATE TABLE
28postgres=# 
29postgres=# insert into messages (id, max_length, default_text, created_on) values (1, 5, null, current_timestamp);
30INSERT 0 1
31postgres=# insert into customized_messages (message_id, message, created_on)  values (1, 'longer than 5', current_timestamp);
32INSERT 0 1
33postgres=# select * from messages;
34 id | max_length | default_text |          created_on           
35----+------------+--------------+-------------------------------
36  1 |          5 |              | 2019-01-18 14:12:59.692075-05
37(1 row)
38postgres=# select * from customized_messages;
39 message_id |    message    |          created_on           
40------------+---------------+-------------------------------
41          1 | longer than 5 | 2019-01-18 14:13:38.226987-05
42(1 row)