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check_fetch_conversion

oracledb_protocol::thin

Function check_fetch_conversion 

Source 
pub fn check_fetch_conversion(
    source: &ColumnMetadata,
    to_ora_type_num: u8,
    to_csfrm: u8,
) -> Option<ColumnMetadata>
Expand description

Mirrors the reference fetch-conversion legality matrix (reference impl/base/var.pyx:113-248 _check_fetch_conversion). Given the metadata of the column being fetched and the Oracle type requested by an output type handler variable, returns the metadata that should be used for the wire define. Conversions that only affect the Python materialization keep the original wire metadata; LOB and JSON sources adjust the define so the server sends inline data. Unsupported pairs return None and the caller is expected to raise DPY-4007.