Data types

Type names are case-insensitive and ignore spaces, underscores, and hyphens during registry lookup. For example, LowCardinality and low_cardinality resolve to the same wrapper. Use the canonical display spellings in maintained DDL.

Numeric

Decimal(P, S) accepts precision 1 through 76 and scale 0 through precision. The registry selects the smallest decimal width that can represent the declared precision.

Use decimals or integer minor units for exact business values. Floating-point values are approximate.

Temporal

Normalize application time zones and precision explicitly. An optional time zone in a type is part of the type descriptor, not a substitute for a system clock policy.

Text and identifiers

• String
• FixedString(N), with byte length 1 through 1,048,576
• Bytes
• UUID
• IPv4 and IPv6
• JSON
• Bool

Text aliases include VARCHAR, TEXT, and CHAR. Common integer aliases include INT, INTEGER, and BIGINT.

Composite and wrappers

Array(UInt64)
Tuple(String, UInt64)
Map(String, String)
Nullable(Decimal(20, 8))
LowCardinality(String)

Nullable(T) adds nullability. LowCardinality(T) is a storage/type hint; its current execution semantics are those of the wrapped value.

The registry also declares Object, Variant, and Dynamic. Operator, index, codec, and wire support is not uniform across every declared composite type. Validate the complete create/insert/query/driver path for a complex type before putting it into a stable schema.

Vectors

Vector(N) is a fixed-dimensional dense numeric vector. The default element type is Float32; Float64 can be declared as the optional element type:

embedding Vector(768)
precise_embedding Vector(128, Float64)

Dimensions range from 1 through 65,535. The current HNSW index path is limited to a bare Float32 vector column. See Vector search.

Conversion

NYXDB applies lossless widening where the type registry permits it. Narrowing, string-to-number conversion, floating-point-to-integer conversion, and removing nullability require an explicit cast:

SELECT cast(raw_amount, 'UInt64')
FROM imported_rows;

Prefer explicit casts at ingestion boundaries so failures are attributable and schema evolution remains reviewable.