Re: Virtual generated columns
Peter Eisentraut <peter@eisentraut.org>
Commits
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API reference →
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Expand virtual generated columns for ALTER COLUMN TYPE
- 5069fef1cfae 18.0 landed
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Eliminate code duplication in replace_rte_variables callbacks
- 363a6e8c6fcf 18.0 landed
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Expand virtual generated columns in the planner
- 1e4351af329f 18.0 landed
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Virtual generated columns
- 83ea6c54025b 18.0 landed
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Additional tests for stored generated columns
- 41084409f635 18.0 landed
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Improve generated_stored test
- 44b61efb7928 18.0 landed
- 86749ea3b766 18.0 landed
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Fix handling of CREATE DOMAIN with GENERATED constraint syntax
- 84a67725cd11 18.0 landed
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Add pg_constraint rows for not-null constraints
- 14e87ffa5c54 18.0 cited
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Put generated_stored test objects in a schema
- 894be11adfa6 18.0 landed
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Rename regress test generated to generated_stored
- b9ed4969250d 18.0 landed
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Small code simplification
- 7ff9afbbd1df 18.0 landed
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Remove useless code
- e26d313bad92 18.0 landed
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Remove useless initializations
- da2aeba8f533 18.0 landed
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doc: Clarify that pg_attrdef also stores generation expressions
- da486d360103 18.0 landed
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Clean out column-level pg_init_privs entries when dropping tables.
- 76618097a6c0 17.0 cited
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Re-implement the ereport() macro using __VA_ARGS__.
- e3a87b4991cc 13.0 cited
On 09.01.25 09:38, jian he wrote:
>> create user foo;
>> create user bar;
>> grant create on schema public to foo;
>> \c - foo
>> create table t1 (id int, ccnum text, ccredacted text generated always as
>> (repeat('*', 12) || substr(ccnum, 13, 4)) virtual);
>> grant select (id, ccredacted) on table t1 to bar;
>> insert into t1 values (1, '1234567890123456');
>> \c - bar
>> select * from t1; -- permission denied
>> select id, ccredacted from t1; -- ok
>
> I think this is expected.
> however once the user can access the pg_catalog,
> then he can use pg_get_expr
> figure out the generation expression.
>
> so here "bar" can figure out the column value of ccnum, i think.
Having access to the expression definition doesn't help you reverse the
computation, if the computation itself is not reversible.