[GENERAL] Foreign key constraint accepted even when not same data type

[Jean-Christian Imbeault]

Is it right for postgres to accept a foreign key constraint when the 
type of the field is not the same as that of the foreign key?

For example:

# Create table a (id int primary key);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index 'a_pkey' 
for table 'a'
CREATE TABLE
# Create table b (id2 text references a(id));

NOTICE:  CREATE TABLE will create implicit trigger(s) for FOREIGN KEY 
check(s)
CREATE TABLE

# \d a
       Table "public.a"
 Column |  Type   | Modifiers
--------+---------+-----------
 id     | integer | not null
Indexes: a_pkey primary key btree (id)
# \d b
     Table "public.b"
 Column | Type | Modifiers
--------+------+-----------
 id2    | text |
Foreign Key constraints: $1 FOREIGN KEY (id2) REFERENCES a(id) ON UPDATE 
NO ACTION ON DELETE NO ACTION

Jean-Christian Imbeault



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