Hi,

Our documentation says:
"All check constraints and not-null constraints on a parent table are
automatically inherited by its children."

Okay, this works as expected:

test=# create table parent (name text primary key);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "parent_pkey" for table "parent"
CREATE TABLE
test=*# create table child (age int) inherits (parent) ;
CREATE TABLE
test=*# \d child
     Table "public.child"
 Column |  Type   | Modifiers
--------+---------+-----------
 name   | text    | not null
 age    | integer |
Inherits: parent


Nice, the 'not null' constraint is in the child-table.


test=*# rollback;
ROLLBACK
test=# create table parent (name text);
CREATE TABLE
test=*# create table child (age int) inherits (parent) ;
CREATE TABLE
test=*# alter table parent add primary key (name);
NOTICE:  ALTER TABLE / ADD PRIMARY KEY will create implicit index "parent_pkey" for table "parent"
ALTER TABLE
test=*# \d child
     Table "public.child"
 Column |  Type   | Modifiers
--------+---------+-----------
 name   | text    |
 age    | integer |
Inherits: parent


Doh, there isn't the 'not null' - modifier. The parent-table contains
this modifier as part of the primary key - definition.


Other test:

test=# create table parent (name text);
CREATE TABLE
test=*# create table child (age int) inherits (parent) ;
CREATE TABLE
test=*# alter table parent alter column name set not null;
ALTER TABLE
test=*# \d child
     Table "public.child"
 Column |  Type   | Modifiers
--------+---------+-----------
 name   | text    | not null
 age    | integer |
Inherits: parent


Okay, we have again the 'not null'.


I think, that's not really clearly. In some case the 'not null' -
constraint are in the child-table, in other case they are not.

Version 8.4.2.

Bug, feature? What have i overlooked?


Andreas
-- 
Andreas Kretschmer
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Responses

• Re: possible bug with inheritance? at 2010-02-16 15:24:01 from Bruce Momjian

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