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Interface INpgsqlTypeMapper

A type mapper, managing how to read and write CLR values to PostgreSQL data types. A type mapper exists for each connection, as well as a single global type mapper (accessible via NpgsqlConnection.GlobalTypeMapper).

Namespace: Npgsql.TypeMapping
Assembly: Npgsql.dll
Syntax
public interface INpgsqlTypeMapper

Properties

DefaultNameTranslator

The default name translator to convert CLR type names and member names.

Declaration
INpgsqlNameTranslator DefaultNameTranslator { get; }
Property Value
Type Description
INpgsqlNameTranslator

Mappings

Enumerates all mappings currently set up on this type mapper.

Declaration
IEnumerable<NpgsqlTypeMapping> Mappings { get; }
Property Value
Type Description
System.Collections.Generic.IEnumerable<NpgsqlTypeMapping>

Methods

AddMapping(NpgsqlTypeMapping)

Adds a new type mapping to this mapper, overwriting any existing mapping in the process.

Declaration
INpgsqlTypeMapper AddMapping(NpgsqlTypeMapping mapping)
Parameters
Type Name Description
NpgsqlTypeMapping mapping
Returns
Type Description
INpgsqlTypeMapper

MapComposite<T>(String, INpgsqlNameTranslator)

Maps a CLR type to a PostgreSQL composite type.

Declaration
INpgsqlTypeMapper MapComposite<T>(string pgName = null, INpgsqlNameTranslator nameTranslator = null)
Parameters
Type Name Description
System.String pgName

A PostgreSQL type name for the corresponding enum type in the database. If null, the name translator given in nameTranslatorwill be used.

INpgsqlNameTranslator nameTranslator

A component which will be used to translate CLR names (e.g. SomeClass) into database names (e.g. some_class). Defaults to NpgsqlSnakeCaseNameTranslator

Returns
Type Description
INpgsqlTypeMapper
Type Parameters
Name Description
T

The .NET type to be mapped

Remarks

CLR fields and properties by string to PostgreSQL enum labels. The translation strategy can be controlled by the nameTranslator parameter, which defaults to NpgsqlSnakeCaseNameTranslator. You can also use the PgNameAttribute on your members to manually specify a PostgreSQL enum label. If there is a discrepancy between the .NET and database labels while a composite is read or written, an exception will be raised.

MapEnum<TEnum>(String, INpgsqlNameTranslator)

Maps a CLR enum to a PostgreSQL enum type.

Declaration
INpgsqlTypeMapper MapEnum<TEnum>(string pgName = null, INpgsqlNameTranslator nameTranslator = null)
    where TEnum : struct, Enum
Parameters
Type Name Description
System.String pgName

A PostgreSQL type name for the corresponding enum type in the database. If null, the name translator given in nameTranslatorwill be used.

INpgsqlNameTranslator nameTranslator

A component which will be used to translate CLR names (e.g. SomeClass) into database names (e.g. some_class). Defaults to NpgsqlSnakeCaseNameTranslator

Returns
Type Description
INpgsqlTypeMapper
Type Parameters
Name Description
TEnum

The .NET enum type to be mapped

Remarks

CLR enum labels are mapped by name to PostgreSQL enum labels. The translation strategy can be controlled by the nameTranslator parameter, which defaults to NpgsqlSnakeCaseNameTranslator. You can also use the PgNameAttribute on your enum fields to manually specify a PostgreSQL enum label. If there is a discrepancy between the .NET and database labels while an enum is read or written, an exception will be raised.

RemoveMapping(String)

Removes an existing mapping from this mapper. Attempts to read or write this type after removal will result in an exception.

Declaration
bool RemoveMapping(string pgTypeName)
Parameters
Type Name Description
System.String pgTypeName

A PostgreSQL type name for the type in the database.

Returns
Type Description
System.Boolean

Reset()

Resets all mapping changes performed on this type mapper and reverts it to its original, starting state.

Declaration
void Reset()

UnmapComposite<T>(String, INpgsqlNameTranslator)

Removes an existing enum mapping.

Declaration
bool UnmapComposite<T>(string pgName = null, INpgsqlNameTranslator nameTranslator = null)
Parameters
Type Name Description
System.String pgName

A PostgreSQL type name for the corresponding composite type in the database. If null, the name translator given in nameTranslatorwill be used.

INpgsqlNameTranslator nameTranslator

A component which will be used to translate CLR names (e.g. SomeClass) into database names (e.g. some_class). Defaults to NpgsqlSnakeCaseNameTranslator

Returns
Type Description
System.Boolean
Type Parameters
Name Description
T

UnmapEnum<TEnum>(String, INpgsqlNameTranslator)

Removes an existing enum mapping.

Declaration
bool UnmapEnum<TEnum>(string pgName = null, INpgsqlNameTranslator nameTranslator = null)
    where TEnum : struct, Enum
Parameters
Type Name Description
System.String pgName

A PostgreSQL type name for the corresponding enum type in the database. If null, the name translator given in nameTranslator will be used.

INpgsqlNameTranslator nameTranslator

A component which will be used to translate CLR names (e.g. SomeClass) into database names (e.g. some_class). Defaults to NpgsqlSnakeCaseNameTranslator

Returns
Type Description
System.Boolean
Type Parameters
Name Description
TEnum
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