Handlers · 2 min read

ClickHouseDecimalToStringPropertyHandler

A property handler that maps the ClickHouse Decimal types into a string property that keeps every digit and the scale.

A property handler that maps the ClickHouse Decimal types (Decimal32, Decimal64, Decimal128 and Decimal256) into a string property. The string keeps every digit and the scale of the value, which a decimal cannot do for the wide Decimal128 and Decimal256 types.

Overview

Name	Description
Class	`ClickHouseDecimalToStringPropertyHandler`
Namespace	`RepoDb.PropertyHandlers.ClickHouse`
Package	RepoDb.ClickHouse
Implements	IPropertyHandler`<object, string>`
Column type	The ClickHouse `Decimal32`, `Decimal64`, `Decimal128` and `Decimal256` types
Property type	`string`

Conversions

Method	Direction	Description
Get	Database to property	Converts the value returned by the driver into its exact, culture-invariant `string`. `null` and `DBNull` are returned as `null`.
Set	Property to database	Parses the culture-invariant `string` into a `ClickHouseDecimal`, to be written into the `Decimal` column. A `null`, empty or white-space value is written as `null`.

Exceptions

Exception	Thrown When
`FormatException`	The string being written is not a valid number.

Usability

Bind the handler to the property that maps to a Decimal128 or Decimal256 column.

Attribute

public class Invoice
{
    public int Id { get; set; }

    [Map("total"), PropertyHandler(typeof(ClickHouseDecimalToStringPropertyHandler))]
    public string Total { get; set; }
}

Once bound, the library invokes the handler automatically when the property is read or written.

using (var connection = new ClickHouseConnection(connectionString))
{
    connection.Insert(new Invoice { Id = 1, Total = "12345678901234567890.123456789" });
    var invoice = connection.Query<Invoice>(e => e.Id == 1).First();
    // invoice.Total keeps every digit and the scale
}

Fluent Mapping

To configure via FluentMapper:

FluentMapper
    .Entity<Invoice>()
    .PropertyHandler<ClickHouseDecimalToStringPropertyHandler>(e => e.Total);

Property Level Mapping

To configure via PropertyHandlerMapper:

PropertyHandlerMapper.Add<Invoice, ClickHouseDecimalToStringPropertyHandler>(e => e.Total, new ClickHouseDecimalToStringPropertyHandler(), true);

Type Level Mapping

To apply the handler to every property of the type string:

PropertyHandlerMapper.Add<string, ClickHouseDecimalToStringPropertyHandler>(new ClickHouseDecimalToStringPropertyHandler(), true);

A type level mapping is process-wide: it is applied to every string property of every entity and connection, not only to the intended column. Prefer the attribute, fluent or property level mapping unless every string property maps to a Decimal column.