PgDatumTypeAttribute

Namespace: Ankus

Assembly: Ankus.Runtime.dll

Maps a managed type to an existing PostgreSQL representation through an explicit datum converter.

[AttributeUsage(AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Enum, AllowMultiple = true, Inherited = false)]
public sealed class PgDatumTypeAttribute : Attribute

This declaration generates conversion registration, not type definitions or input/output functions. The converter implements IPgDatumReader<T>, IPgDatumWriter<T>, or both for this exact managed type. A default generic declaration is a template selected by fully constructed roots in supported generated signatures or exact managed PgSqlTypeProvider declarations. Each selected construction must have an exact reader or writer interface on its supplied or inferred closed converter. An open generic converter definition is closed at compile time from its exact reader/writer interface patterns. Every parameter, including containing-type parameters, must have one unambiguous assignment satisfying the C# constraints. No runtime reflection or open-ended registration is generated. An explicit managed-type declaration selects one closed construction and registers a local root even without a generated signature. It takes precedence over the optional default declaration on that type. Exact declarations can assign distinct SQL identities and converters to different closed constructions. Supported paths are scalar and array generated callbacks, set/TABLE and aggregate slots, declared SPI/function parameters, typed SPI scalar and catalog/native-address function results, SpiRow and PgHeapTuple cells read or written with the mapped type, PgDatum.Create, and explicit PgDatum.Read<T> calls. One array layer uses the scalar converter with exact element and array identity, preserving NULL and shape. Value-type mappings can add PgRangeType to compose the same converter into finite PgRange<T> bounds and arrays of those ranges. Range and scalar SQL identities and ownership remain independent. Readable mappings may declare PgEquality, PgOrdering and PgHashing; generated helpers require no writer. Native-address calls retain the caller’s responsibility for the actual result type and representation. A row or tuple cell must have exactly the mapped PostgreSQL type; the indexer and other types do not read it. A reader must return independent managed data; retaining a checked PgDatum does not detach its storage.

Inheritance: object, Attribute

Constructors

PgDatumTypeAttribute(string, Type)

Maps a managed type to an existing PostgreSQL representation through an explicit datum converter.

public PgDatumTypeAttribute(string name, Type converter)

Parameters:

name — string

The exact unquoted PostgreSQL type identifier.

converter — Type

The closed converter or inferable generic definition with an accessible parameterless constructor.

This declaration generates conversion registration, not type definitions or input/output functions. The converter implements IPgDatumReader<T>, IPgDatumWriter<T>, or both for this exact managed type. A default generic declaration is a template selected by fully constructed roots in supported generated signatures or exact managed PgSqlTypeProvider declarations. Each selected construction must have an exact reader or writer interface on its supplied or inferred closed converter. An open generic converter definition is closed at compile time from its exact reader/writer interface patterns. Every parameter, including containing-type parameters, must have one unambiguous assignment satisfying the C# constraints. No runtime reflection or open-ended registration is generated. An explicit managed-type declaration selects one closed construction and registers a local root even without a generated signature. It takes precedence over the optional default declaration on that type. Exact declarations can assign distinct SQL identities and converters to different closed constructions. Supported paths are scalar and array generated callbacks, set/TABLE and aggregate slots, declared SPI/function parameters, typed SPI scalar and catalog/native-address function results, SpiRow and PgHeapTuple cells read or written with the mapped type, PgDatum.Create, and explicit PgDatum.Read<T> calls. One array layer uses the scalar converter with exact element and array identity, preserving NULL and shape. Value-type mappings can add PgRangeType to compose the same converter into finite PgRange<T> bounds and arrays of those ranges. Range and scalar SQL identities and ownership remain independent. Readable mappings may declare PgEquality, PgOrdering and PgHashing; generated helpers require no writer. Native-address calls retain the caller’s responsibility for the actual result type and representation. A row or tuple cell must have exactly the mapped PostgreSQL type; the indexer and other types do not read it. A reader must return independent managed data; retaining a checked PgDatum does not detach its storage.

PgDatumTypeAttribute(Type, string, Type)

Maps one exact closed construction of the annotated type independently of its other constructions.

public PgDatumTypeAttribute(Type managedType, string name, Type converter)

Parameters:

managedType — Type

The closed managed type whose definition carries this attribute.

name — string

The exact unquoted PostgreSQL type identifier.

converter — Type

The closed converter or inferable generic definition with an accessible parameterless constructor.

Properties

Converter

Gets the supplied reader or writer type, whose generic arguments may be inferred at compile time.

public Type Converter { get; }

Value: Type

ManagedType

Gets the exact closed managed identity, or null for the annotated type’s default mapping.

public Type? ManagedType { get; }

Value: Type

Name

Gets the exact catalog type identifier.

public string Name { get; }

Value: string

Origin

Gets or sets whether the SQL type is supplied by this extension or an existing external schema.

public PgTypeOrigin Origin { get; set; }

Value: PgTypeOrigin

Schema

Gets or sets the fixed schema. External mappings require an explicit schema.

public string? Schema { get; set; }

Value: string