Enum fdb_rl::key_expression::FieldNullInterpretation

pub(crate) enum FieldNullInterpretation {
    Distinct,
    NotDistinct,
    NotNull,
}

How to interpret missing value (NULL) or assert that value must always be present.

Variants

Distinct

Missing value (NULL) are allowed multiple times in unique index (PostgreSQL NULLS DISTINCT, Java RecordLayer Evaluated.Nullstandin.NULL, RecordMetaDataProto.Field.NullInterpretation.NOT_UNIQUE).

This is the default for PostgreSQL and Java RecordLayer.

NotDistinct

Missing value (NULL) cannot be repeated in a unique index (PostgreSQL NULLS NOT DISTINCT, Java RecordLayer Evaluated.Nullstandin.NULL_UNIQUE, RecordMetaDataProto.Field.NullInterpretation.UNIQUE).

This is very restrictive as a column can have only one NULL value.

NotNull

Field is not NULL (PostgreSQL NOT NULL).

Note: Here we are following PostgreSQL semantics and not Java RecordLayer semantics. In Java RecordLayer Evaluated.Nullstandin.NOT_NULL and RecordMetaDataProto.Field.NullInterpretation.NOT_NULL means when a field is missing, the Protobuf default value for that field is returned. In our case, all fields have presence information. The field must be present, and we return that value. When NotNull variant is specified, and the field is not present, it is an error.

Trait Implementations

impl From<FieldNullInterpretation> for FieldNullInterpretationInternalV1

fn from( field_null_interpretation: FieldNullInterpretation ) -> FieldNullInterpretationInternalV1

Converts to this type from the input type.

impl From<FieldNullInterpretationInternalV1> for FieldNullInterpretation

fn from( pb_field_null_interpretation_internal_v1: FieldNullInterpretationInternalV1 ) -> FieldNullInterpretation

Converts to this type from the input type.