Enum LinkProperties 

pub enum LinkProperties {
    ForeignKey {
        source_column: &'static str,
        target_column: &'static str,
        cardinality: Cardinality,
        source_id_type: Option<SemanticType>,
        requires_mapping: Option<&'static str>,
        nullable: bool,
        note: Option<&'static str>,
        extra_key_columns: Option<&'static [(&'static str, &'static str)]>,
    },
    Union {
        discriminator_column: Option<&'static str>,
        discriminator_value: Option<&'static str>,
        note: Option<&'static str>,
    },
    MapsTo {
        source_column: &'static str,
        target_column: &'static str,
        via: Option<&'static str>,
        from_type: Option<SemanticType>,
        to_type: Option<SemanticType>,
        note: Option<&'static str>,
    },
    DependsOn {
        source_column: &'static str,
        target_column: &'static str,
        source_id_type: Option<SemanticType>,
        requires_mapping: Option<&'static str>,
    },
    Measures {
        source_column: &'static str,
        target_column: &'static str,
        metric: &'static str,
        source_id_type: Option<SemanticType>,
        requires_mapping: Option<&'static str>,
        note: Option<&'static str>,
        extra_key_columns: Option<&'static [(&'static str, &'static str)]>,
    },
}

Typed properties for an ontology link. Serialized to the properties JSONB column in mz_ontology_link_types. The kind field is inlined from the enum variant name via #[serde(tag = "kind")].

Choosing the right variant matters:

• LinkProperties::ForeignKey: the source entity has a column whose value is an ID that directly references a row in the target entity. Use this when there is an explicit FK column (e.g. schema_id -> schema).
• LinkProperties::DependsOn: this entity logically depends on the target entity via a graph-edge table (e.g. mz_compute_dependencies records that a compute object depends on another object). The source_column is the column in this entity that holds the dependent’s ID; target_column is the column in the target entity being depended upon. Use this for dependency-graph tables, not ForeignKey.
• LinkProperties::Union: the source entity is a superset view that contains the target entity as a subset, optionally filtered by a discriminator column.
• LinkProperties::MapsTo: the source entity provides an ID translation to the target entity, possibly via an intermediate table or across ID namespaces.
• LinkProperties::Measures: the source entity records metric measurements about the target entity.

Variants

ForeignKey

A foreign-key relationship: source_column in the source entity references target_column in the target entity.

Fields

source_column: &'static str

Column in the source entity that holds the reference.

target_column: &'static str

Column in the target entity being referenced (usually id).

cardinality: Cardinality

How many source rows may reference a single target row.

source_id_type: Option<SemanticType>

Semantic type of the source column, if it carries an ID that requires type-aware resolution (e.g. CatalogItemId, GlobalId).

requires_mapping: Option<&'static str>

Intermediate mapping relation needed when source_id_type does not directly match the target entity’s ID type (e.g. mz_internal.mz_object_global_ids to go from GlobalId to catalog object).

nullable: bool

True when the source column may be NULL (the reference is optional).

note: Option<&'static str>

Free-form annotation for cases that need extra context.

extra_key_columns: Option<&'static [(&'static str, &'static str)]>

Additional (source_column, target_column) pairs that together with source_column/target_column form a composite join key. Used for _per_worker entities whose primary key is (id, worker_id), and for message-count raw relations whose join key includes worker IDs. Serialized as an array; omitted when None.

Union

A union relationship: the source entity is a superset view that includes the target entity, optionally filtered by a discriminator column/value.

Fields

discriminator_column: Option<&'static str>

Column used to discriminate between subtypes (e.g. type).

discriminator_value: Option<&'static str>

Value of discriminator_column that selects the target entity.

note: Option<&'static str>

Free-form annotation for cases that need extra context.

MapsTo

A mapping relationship: the source entity maps to the target entity, optionally via an intermediate table and/or with an ID-type conversion.

Fields

source_column: &'static str

Column in the source entity that holds the ID to map from.

target_column: &'static str

Column in the target entity being mapped to.

via: Option<&'static str>

Intermediate relation used to perform the mapping.

from_type: Option<SemanticType>

Semantic type of the source ID before mapping.

to_type: Option<SemanticType>

Semantic type of the target ID after mapping.

note: Option<&'static str>

Free-form annotation for cases that need extra context.

DependsOn

A dependency relationship: this entity directly depends on the target entity (e.g. a materialization that references an object).

Fields

source_column: &'static str

Column in this entity that holds the dependency ID.

target_column: &'static str

Column in the target entity being depended upon (usually id).

source_id_type: Option<SemanticType>

Semantic type of the source column.

requires_mapping: Option<&'static str>

Intermediate mapping relation needed when source_id_type does not directly match the target entity’s ID type (e.g. GlobalId → mz_internal.mz_object_global_ids to reach a catalog object).

Measures

A metric relationship: the source entity records measurements of a named metric on the target entity.

Fields

source_column: &'static str

Column in the source entity that references the target entity.

target_column: &'static str

Column in the target entity being measured (usually id).

metric: &'static str

Name of the metric being measured (e.g. cpu_time_ns).

source_id_type: Option<SemanticType>

Semantic type of the source column, if ID-type resolution is needed.

requires_mapping: Option<&'static str>

Intermediate mapping relation needed when the source ID type differs from the target entity’s ID type.

note: Option<&'static str>

Free-form annotation for cases that need extra context.

extra_key_columns: Option<&'static [(&'static str, &'static str)]>

Additional (source_column, target_column) pairs that together with source_column/target_column form a composite join key.

Implementations

impl LinkProperties

pub const fn fk( source_column: &'static str, target_column: &'static str, cardinality: Cardinality, ) -> Self

Basic foreign-key link with no optional fields set.

pub const fn fk_nullable( source_column: &'static str, target_column: &'static str, cardinality: Cardinality, ) -> Self

Foreign-key link where the source column may be NULL.

pub const fn fk_typed( source_column: &'static str, target_column: &'static str, cardinality: Cardinality, source_id_type: SemanticType, ) -> Self

Foreign-key link whose source column carries a typed ID (e.g. CatalogItemId) but does not require an intermediate mapping table.

pub const fn fk_mapped( source_column: &'static str, target_column: &'static str, cardinality: Cardinality, source_id_type: SemanticType, requires_mapping: &'static str, ) -> Self

Foreign-key link whose source column carries a typed ID that requires an intermediate mapping table to resolve (e.g. GlobalId → mz_internal.mz_object_global_ids).

pub const fn fk_composite( source_column: &'static str, target_column: &'static str, cardinality: Cardinality, extra_key_columns: &'static [(&'static str, &'static str)], ) -> Self

Foreign-key link with a composite join key. extra_key_columns lists additional (source_column, target_column) pairs beyond the primary source_column/target_column pair. Examples:

• &[("worker_id", "worker_id")] for _per_worker entities
• &[("from_worker_id", "worker_id")] for message-count raw relations

pub const fn union_disc( discriminator_column: &'static str, discriminator_value: &'static str, ) -> Self

Union link filtered by a discriminator column/value pair.

pub const fn measures( source_column: &'static str, target_column: &'static str, metric: &'static str, ) -> Self

Basic measures link with no optional fields set.

pub const fn measures_composite( source_column: &'static str, target_column: &'static str, metric: &'static str, extra_key_columns: &'static [(&'static str, &'static str)], ) -> Self

Measures link with a composite join key.

pub const fn measures_mapped( source_column: &'static str, target_column: &'static str, metric: &'static str, source_id_type: SemanticType, requires_mapping: &'static str, ) -> Self

Measures link whose source ID requires an intermediate mapping table.

Trait Implementations

impl Clone for LinkProperties

fn clone(&self) -> LinkProperties

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LinkProperties

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for LinkProperties

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LinkProperties

fn eq(&self, other: &LinkProperties) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for LinkProperties

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for LinkProperties

impl Eq for LinkProperties

impl StructuralPartialEq for LinkProperties