Re: Virtual generated columns
Tom Lane <tgl@sss.pgh.pa.us>
Commits
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the thread's linked commits as JSON, with link sources.
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
Peter Eisentraut <peter@eisentraut.org> writes:
> On 03.12.24 15:15, jian he wrote:
>> SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE
>> attgenerated IN ('v') and (attnotnull or not atthasdef);
> I don't understand what the purpose of testing attnotnull is. That is
> independent of attgenerated, I think.
Does it make any sense to set NOT NULL on a generated column (virtual
or otherwise, but especially virtual)? What is the system supposed
to do if the expression evaluates to null? That concern generalizes
to any constraint really. Even if we checked it at row storage time,
there's no real guarantee that the expression is immutable enough
to pass the constraint later.
regards, tom lane