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Change the type of column used in other views

create table base (name character varying(255));                                                                                                                                                        
create view v1 as select *, now() from base;                                                        
create view v2 as select * from v1 where name = 'joe';
alter table base alter column name type text;

Gives this error:

cannot alter type of a column used by a view or rule
DETAIL:  rule _RETURN on view v1 depends on column "name"

This is pretty annoying because now I need to recreate all the views that reference the column base.name. This is especially annoying when I have views that reference other views.

What I would like to do is something like:

select recreate_views('v1', 'v2', 'alter table base alter column name type text');

And let the function get the definitions of the form for v1 and v2, drop them, run the specified code and recreate v1 and v2. If I could use Ruby, I probably would have a function to take the / block / lambda function, for example

recreate_views 'v1', 'v2' do
  alter table base alter column name type text
end

Is something like this possible? Are there any utilities that do something similar?

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2 answers

, , , args, VARIADIC.

CREATE OR REPLACE FUNCTION recreate_views(run_me text, VARIADIC views text[])
  RETURNS void
AS  $$
DECLARE
  view_defs text[];
  i integer;
  def text;
BEGIN
  for i in array_lower(views,1) .. array_upper(views,1) loop
    select definition into def from pg_views where viewname = views[i];
    view_defs[i] := def;
    EXECUTE 'DROP VIEW ' || views[i];
  end loop;

  EXECUTE run_me;

  for i in reverse array_upper(views,1) .. array_lower(views,1) loop
    def = 'CREATE OR REPLACE VIEW ' || quote_ident( views[i] ) || ' AS ' || view_defs[i];
    EXECUTE def;
  end loop;

END
$$
LANGUAGE plpgsql;
+7

, , , , :

for i in array_lower(views,1) .. array_upper(views,1) loop
    select definition into def from pg_views where viewname = views[i];
    view_defs[i] := def;
    IF def IS NOT NULL THEN
        EXECUTE 'DROP VIEW ' || schema_name || '.' || views[i];
    END IF;
end loop;   

    EXECUTE run_me;

for i in reverse array_upper(views,1) .. array_lower(views,1) loop
    IF view_defs[i] IS NOT NULL THEN
        def = 'CREATE OR REPLACE VIEW ' || schema_name || '.' || views[i] || ' AS ' || view_defs[i];
        EXECUTE def;
    END IF;
end loop;
+1

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