DESCRIBE()

All functions > METADATA > DESCRIBE()

Returns catalog and type metadata for an expression as a typed ROW.

Signatures

Returns: Metadata fields; nested bags are JSON VARCHAR when present

DESCRIBE(expr: T) → ROW(name VARCHAR, type VARCHAR, entity VARCHAR, unit VARCHAR, description VARCHAR, status VARCHAR, attributes VARCHAR, presentation VARCHAR, inputs VARCHAR, dependencies VARCHAR, formula VARCHAR, literal_status VARCHAR, grain VARCHAR, additivity VARCHAR, determined_by VARCHAR)

Notes

• Works on any expression (literals become unnamed features)
• type matches TYPEOF(expr) (FeatureQL type string)
• entity and unit come from the inferred type (and feature unit spelling when authored)
• name, description, status, attributes, and presentation are filled for named features; NULL for unnamed expressions
• attributes and presentation are JSON objects serialized as VARCHAR when non-empty
• inputs is a JSON array of direct upstream INPUT feature names (empty → NULL)
• dependencies is a JSON object of name → DAG layer from the compiler graph (empty → NULL)
• formula is the FeatureQL formula text (feature.formula or pretty-printed expression); may be NULL if formatting fails
• literal_status is LITERAL, LITERAL_COMPUTED, or NOT_LITERAL when classified; NULL if unavailable
• grain is JSON direct_grain (empty array when scalar)
• additivity and determined_by come from the semantic profile
• Distinct from the DESCRIBE feature; statement, which returns a JSON cell of compiler fields

See also

• Metadata functions

Examples

Literals

RETURN
    -- Type field matches TYPEOF
    f1 := DESCRIBE(1)[type],
    -- Unnamed expressions have no catalog name
    f2 := DESCRIBE(1)[name]
;