Re: changing the size of a column without losing data

From: "Mark Seftel" <mark(at)trustemail(dot)com>
To: <pgsql-novice(at)postgresql(dot)org>
Subject: [NOVICE] changing the size of a column without losing data
Date sent: Thu, 22 Aug 2002 19:43:57 +0200

Like I said I make a lot of typo's

What I meant to write was:

begin;

ALTER table table0 RENAME TO table1;

DROP INDEX table0_pkey;

CREATE TEMPORARY table table1temp() INHERITS (table1);

INSERT INTO table1temp SELECT * FROM table1;

CREATE table table0(
field varchar(50) PRIMARY KEY);

INSERT INTO table0 SELECT * FROM table1temp;

DROP table table1temp;

DROP table table1;
end;

Though looking at it again I'm not sure why I used the temporary
table, this seems to work as well:

begin;

ALTER table table0 RENAME TO table1;

DROP INDEX table0_pkey;

CREATE table table0(
field varchar(50) PRIMARY KEY);

INSERT INTO table0 SELECT * FROM table1;

DROP table table1;
end;

Watch out for the data in the old column(100) being too big for the
new one (50),
Hope this actually helps

Paul Butler

> hi,
>
> How would i change a field which is currently char100 to char50?
>
> have tried:
> ALTER TABLE outlets MODIFY description varchar(50);
>
> but get error:
> parser: parse error at or near "modify"
>
> what is the correct command.
>
> Thx
>
> Mark
>
>
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