Thread: Create type

Create type

From
Renaud Tthonnart
Date:
If I can't use nested tables, how can I create a
type that will be a kind of  "dynamic list of structure".

regards,
Renaud THONNART


RE:Create type

From
Renaud Tthonnart
Date:
Richard Huxton wrote:

> From: "Renaud Tthonnart" <thonnart@amwdb.u-strasbg.fr>
>
> > If I can't use nested tables, how can I create a
> > type that will be a kind of  "dynamic list of structure".
>
> Sorry Renaud, I'm not sure it's clear what you're trying to do. Could
you
> post an example of what you're trying to achieve to the list? That'd
> probably help
>
> Ta
>
> - Richard Huxton

Ok. First I wanted to use nested tables. But I think it is not possible.

Then I decided to create
a type that will made the same function, a type that will be like a C
structure. This type would contain
an integer and a string like (1,'aaa'). Then I would have made a list or

an
array with this type.
Am I clear? Sorry if not, my English is poor.

Thank you for your help.
Renaud THONNART



Re: Create type

From
"Eric G. Miller"
Date:
On Tue, Feb 27, 2001 at 09:11:43AM +0100, Renaud Tthonnart wrote:
> Richard Huxton wrote:
> >
> > Sorry Renaud, I'm not sure it's clear what you're trying to do.
> > Could you post an example of what you're trying to achieve to the
> > list? That'd probably help
>
> Ok. First I wanted to use nested tables. But I think it is not
> possible.
>
> Then I decided to create a type that will made the same function, a
> type that will be like a C structure. This type would contain an
> integer and a string like (1,'aaa'). Then I would have made a list or
>
> an array with this type.  Am I clear? Sorry if not, my English is
> poor.

I think the original question still stands.  What are you trying do?
Can't you map your "structure" to a regular table?  A list of struct's
containing one integer and one string sounds like a table containing
one integer and one string (with the possible addition of an extra
key field if the integer is not already an identifier).

CREATE TABLE list_struct (
  i  integer NOT NULL,
  c  varchar(255) NOT NULL
      CHECK (char_length(c) > 0),
  PRIMARY KEY (i, c)
);

--
Eric G. Miller <egm2@jps.net>

Re: Create type

From
"Richard Huxton"
Date:
From: "Renaud Tthonnart" <thonnart@amwdb.u-strasbg.fr>


> If I can't use nested tables, how can I create a
> type that will be a kind of  "dynamic list of structure".
>
> regards,
> Renaud THONNART
>
> Ok. First I wanted to use nested tables. But I think it is not possible.
> Then I decided to create
> a type that will made the same function, a type that will be like a C
> structure. This type would contain
> an integer and a string like (1,'aaa'). Then I would have made a list or
an
> array with this type.
> Am I clear? Sorry if not, my English is poor.
>
> Thank you for your help.
> Renaud THONNART

Ah - you can define your own types using C and then should be able to have
an array of them. Never done this myself, but the relevant information is in
the Programmer's Guide - 13. Extending SQL: Types

You will probably end up building supporting functions and operators for the
type too.

- Richard Huxton


Re: Create type

From
Renaud Tthonnart
Date:
"Eric G. Miller" wrote:

> > Ok. First I wanted to use nested tables. But I think it is not
> > possible.
> >
> > Then I decided to create a type that will made the same function, a
> > type that will be like a C structure. This type would contain an
> > integer and a string like (1,'aaa'). Then I would have made a list or
> >
> > an array with this type.  Am I clear? Sorry if not, my English is
> > poor.
>
> I think the original question still stands.  What are you trying do?
> Can't you map your "structure" to a regular table?  A list of struct's
> containing one integer and one string sounds like a table containing
> one integer and one string (with the possible addition of an extra
> key field if the integer is not already an identifier).
>
> CREATE TABLE list_struct (
>   i  integer NOT NULL,
>   c  varchar(255) NOT NULL
>       CHECK (char_length(c) > 0),
>   PRIMARY KEY (i, c)
> );
>
> --
> Eric G. Miller <egm2@jps.net>

Of course I can do that but I need one table of that kind for each row of
1000 tables that contain 10000 rows each.
That's the reason why I would have like using nested table.
Olk. I see that I want to do is not possible.
I just want to say that it is a bit disapointing that PostgreSQL that is
qualified OR/DBMS  don't offer a way to create nested tables.
I think that will be interresting to add it in future versions.

Renaud THONNART



Re: Create type

From
Renaud Tthonnart
Date:
Richard Huxton wrote:

> > Ok. First I wanted to use nested tables. But I think it is not possible.
> > Then I decided to create
> > a type that will made the same function, a type that will be like a C
> > structure. This type would contain
> > an integer and a string like (1,'aaa'). Then I would have made a list or
> an
> > array with this type.
> > Am I clear? Sorry if not, my English is poor.
> >
> > Thank you for your help.
> > Renaud THONNART
>
> Ah - you can define your own types using C and then should be able to have
> an array of them. Never done this myself, but the relevant information is in
> the Programmer's Guide - 13. Extending SQL: Types
>
> You will probably end up building supporting functions and operators for the
> type too.
>
> - Richard Huxton

Ok, thank you for your help Richard !
Renaud THONNART