On 12/7/18 3:17 PM, Kevin Brannen wrote:
> I'm running Pg 9.6.5 if it matters...
>
> I'm trying to drop a value from an ENUM (type) and it seems like I'm
> following the fine manual yet I still get an error. For example:
>
> nms=# create type alphabet as enum ('a', 'b', 'c', 'd');
>
> CREATE TYPE
>
> nms=# alter type alphabet drop attribute if exists 'c';
>
> ERROR: 42601: syntax error at or near "'c'"
>
> LINE 1: alter type alphabet drop attribute if exists 'c';
>
> ^
>
> LOCATION: scanner_yyerror, scan.l:1086
>
> What am I doing wrong? The goal is to get rid of the 'c' value from
> the enum. Yes, you can assume I've already removed of all the 'c'
> values in the table where it's used.
https://www.postgresql.org/docs/10/datatype-enum.html
"Although enum types are primarily intended for static sets of values, there is
support for adding new values to an existing enum type, and for renaming values
(see ALTER TYPE). Existing values cannot be removed from an enum type, nor can
the sort ordering of such values be changed, short of dropping and re-creating
the enum type.
>
> Or does that statement not do what I think it does and I have to do
> the "create new type, change the table to use the new type, drop old
> type, rename new type to old type" routine?
Adrian,
Thanks, I hadn't seen that "existing values cannot be removed from an enum
type" since I was looking on the ALTER TYPE page.
So, can you (or anyone) help me understand what "alter type <type> drop
attribute" is meant to do? I don't see "attribute" on the page you reference.
Thanks,
Kevin
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