PostgreSQL: Documentation: 18: F.10. cube — a multi-dimensional cube data type

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F.10. cube — a multi-dimensional cube data type
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F.10. cube — a multi-dimensional cube data type #

F.10.1. Syntax
F.10.2. Precision
F.10.3. Usage
F.10.4. Defaults
F.10.5. Notes
F.10.6. Credits

This module implements a data type cube for representing multidimensional cubes.

This module is considered “trusted”, that is, it can be installed by non-superusers who have CREATE privilege on the current database.

F.10.1. Syntax #

Table F.1 shows the valid external representations for the cube type. x, y, etc. denote floating-point numbers.

Table F.1. Cube External Representations

External Syntax	Meaning
`x`	A one-dimensional point (or, zero-length one-dimensional interval)
`(x)`	Same as above
`x1,x2,...,xn`	A point in n-dimensional space, represented internally as a zero-volume cube
`(x1,x2,...,xn)`	Same as above
`(x),(y)`	A one-dimensional interval starting at `x` and ending at `y` or vice versa; the order does not matter
`[(x),(y)]`	Same as above
`(x1,...,xn),(y1,...,yn)`	An n-dimensional cube represented by a pair of its diagonally opposite corners
`[(x1,...,xn),(y1,...,yn)]`	Same as above

It does not matter which order the opposite corners of a cube are entered in. The cube functions automatically swap values if needed to create a uniform “lower left — upper right” internal representation. When the corners coincide, cube stores only one corner along with an “is point” flag to avoid wasting space.

White space is ignored on input, so [(x),(y)] is the same as [ ( x ), ( y ) ].

F.10.2. Precision #

Values are stored internally as 64-bit floating point numbers. This means that numbers with more than about 16 significant digits will be truncated.

F.10.3. Usage #

Table F.2 shows the specialized operators provided for type cube.

Table F.2. Cube Operators

Operator Description
`cube` `&&` `cube` → `boolean` Do the cubes overlap?
`cube` `@>` `cube` → `boolean` Does the first cube contain the second?
`cube` `<@` `cube` → `boolean` Is the first cube contained in the second?
`cube` `->` `integer` → `float8` Extracts the `n`-th coordinate of the cube (counting from 1).
`cube` `~>` `integer` → `float8` Extracts the `n`-th coordinate of the cube, counting in the following way: `n` = 2 * `k` - 1 means lower bound of `k`-th dimension, `n` = 2 * `k` means upper bound of `k`-th dimension. Negative `n` denotes the inverse value of the corresponding positive coordinate. This operator is designed for KNN-GiST support.
`cube` `<->` `cube` → `float8` Computes the Euclidean distance between the two cubes.
`cube` `<#>` `cube` → `float8` Computes the taxicab (L-1 metric) distance between the two cubes.
`cube` `<=>` `cube` →

Operator

Description

cube && cube → boolean

Do the cubes overlap?

cube @> cube → boolean

Does the first cube contain the second?

cube <@ cube → boolean

Is the first cube contained in the second?

cube -> integer → float8

Extracts the n-th coordinate of the cube (counting from 1).

cube ~> integer → float8

Extracts the n-th coordinate of the cube, counting in the following way: n = 2 * k - 1 means lower bound of k-th dimension, n = 2 * k means upper bound of k-th dimension. Negative n denotes the inverse value of the corresponding positive coordinate. This operator is designed for KNN-GiST support.

cube <-> cube → float8

Computes the Euclidean distance between the two cubes.

cube <#> cube → float8

Computes the taxicab (L-1 metric) distance between the two cubes.

cube <=> cube →