- C++ 76.6%
- sql 17%
- Python 2.6%
- C 1.7%
- Julia 0.9%
- Other 1%
4820e7a557### Summary
information_schema.columns has always exposed is_generated and
generation_expression columns (as required by the SQL standard), but
both were hardcoded as NULL::VARCHAR which makes them unusable for
discovering generated columns.
This PR fixes that by:
- Adding is_generated (BOOLEAN) and generation_expression (VARCHAR) to
the `duckdb_columns` table function, sourced from the existing
ColumnDefinition::Generated() and
ColumnDefinition::GeneratedExpression() internals
- Wiring information_schema.columns to use these real values:
is_generated returns 'ALWAYS' or 'NEVER' (consistent with PostgreSQL),
and generation_expression returns the expression string for generated
columns and NULL otherwise
### Before
```
CREATE TABLE t (
i INT,
j INT GENERATED ALWAYS AS (i + 1),
k VARCHAR DEFAULT 'hello'
);
SELECT column_name, is_generated, generation_expression
FROM information_schema.columns WHERE table_name = 't';
-- is_generated and generation_expression are always NULL
```
### After
```
SELECT column_name, is_generated, generation_expression
FROM information_schema.columns WHERE table_name = 't';
-- i | NEVER | NULL
-- j | ALWAYS | CAST((i + 1) AS INTEGER)
-- k | NEVER | NULL
```
### Testing
Extended test/sql/generated_columns/virtual/gcol_duckdb_columns.test
with assertions covering both duckdb_columns and
information_schema.columns.
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| data | ||
| examples | ||
| extension | ||
| logo | ||
| scripts | ||
| src | ||
| test | ||
| third_party | ||
| tools | ||
| .clang-format | ||
| .clang-tidy | ||
| .clangd | ||
| .codecov.yml | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .sanitizer-leak-suppressions.txt | ||
| .sanitizer-thread-suppressions.txt | ||
| AI_POLICY.md | ||
| CITATION.cff | ||
| CLAUDE.md | ||
| CMakeLists.txt | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| Doxyfile | ||
| DuckDBConfig.cmake.in | ||
| DuckDBConfigVersion.cmake.in | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| SECURITY.md | ||
DuckDB
DuckDB is a high-performance analytical database system. It is designed to be fast, reliable, portable, and easy to use. DuckDB provides a rich SQL dialect with support far beyond basic SQL. DuckDB supports arbitrary and nested correlated subqueries, window functions, collations, complex types (arrays, structs, maps), and several extensions designed to make SQL easier to use.
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