Custom type handling

[matthias-Q]

This PR adds handling of custom types in Postgres:

• create type
  • enum
  • range
  • object types
• drop type
• alter type
  • rename, rename attributes
  • drop, add, alter attributes
  • ownership & schema
• create table with a column as a custom type
• select from a table with a custom attribute (dot notation)

Remarks:
We have many statement with a set ( KEY = VALUE) section. The keys are often specific, but as of now we allow everything. They could be technically treated as keywords, but we have to add a lot of different variants. Or we keep it as it is and the parser will be more permissive.
(I think I asked this question before, but I don't remember the outcome of the discussion...)

References:
https://www.postgresql.org/docs/current/sql-createtype.html
https://www.postgresql.org/docs/current/sql-altertype.html
https://www.postgresql.org/docs/current/sql-droptype.html

Closes #184

[dmfay]

We have many statement with a set ( KEY = VALUE) section. The keys are often specific, but as of now we allow everything. They could be technically treated as keywords, but we have to add a lot of different variants. Or we keep it as it is and the parser will be more permissive.
(I think I asked this question before, but I don't remember the outcome of the discussion...)

a lot of these get really dialect-specific so imo it's fine to be permissive with them

[matthias-Q]

I have change from identifier to literal for add/rename values of a custom type. It is now correct. However, it will also parse it as correct, when these fields are wrapped in double quotes. I think only single quotes will work. Maybe we should split the _literal_string in two hidden nodes so that we can used them separately.

Also, on my testing postgres instance this does not work:

ALTER TYPE color RENAME VALUE 'purple' TO 'mauve';

It is taken directly from the docs and it complaints about the keyword value. Am I missing something very obvious here?

[dmfay]

I have change from identifier to literal for add/rename values of a custom type. It is now correct. However, it will also parse it as correct, when these fields are wrapped in double quotes. I think only single quotes will work. Maybe we should split the _literal_string in two hidden nodes so that we can used them separately.

Also, on my testing postgres instance this does not work:

ALTER TYPE color RENAME VALUE 'purple' TO 'mauve';

It is taken directly from the docs and it complaints about the keyword value. Am I missing something very obvious here?

is the color type still an enum or did you recreate it as a composite while testing things?

[local] dian#dian= create type color as enum ('purple', 'red', 'yellow');
CREATE TYPE
Time: 14.847 ms
[local] dian#dian= alter type color rename value 'purple' to 'mauve';
ALTER TYPE
Time: 14.992 ms

re literal_string I think some dialects treat single/double quotes interchangeably but don't recall which offhand

[matthias-Q]

I just had a super old postgres version. I have updated to 15.3 and now it works.