Implementation:ClickHouse ClickHouse Base Types

Knowledge Sources	ClickHouse
Domains	Data_Types, Core
Last Updated	2026-02-08 00:00 GMT

Overview

Fundamental type aliases used throughout ClickHouse.

Description

Defines Int8/UInt8/Int16/UInt16/Int32/UInt32/Int64/UInt64/Float32/Float64/String aliases with specific semantics (UInt8=char8_t, Int8=_BitInt(8)).

Usage

Use as the standard numeric types throughout ClickHouse codebase for consistency.

Code Reference

Source Location

• Repository: ClickHouse
• File: base/base/types.h
• Lines: 1-38

Signature

using UInt8 = char8_t;
using Int8 = signed _BitInt(8);
using UInt16 = uint16_t;
using UInt32 = uint32_t;
using UInt64 = uint64_t;
using Int16 = int16_t;
using Int32 = int32_t;
using Int64 = int64_t;
using Float32 = float;
using Float64 = double;
using String = std::string;

Import

#include <base/types.h>

Usage Examples

#include <base/types.h>

// Use standard ClickHouse types
UInt64 user_id = 123456;
Int32 temperature = -5;
Float64 price = 19.99;
String name = "Alice";

// These are the fundamental types used throughout ClickHouse
UInt8 byte = 0xFF;
Int8 signed_byte = -128;

Related Pages

• Principle:ClickHouse_ClickHouse_Fundamental_Type_Aliases