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Values

Each of the types mentioned in the data model is a subset of an all-encompassing type called a value.

Comparing and ordering values

While it is unsurprising that a data type can be compared with itself, it may be surprising that different types can also be compared with each other.

RETURN 9 > 1;            // Returns true
RETURN [] > time::now(); // Also returns true

This comparison is possible because every type in SurrealDB is a subset of value, and a comparison of any type with another is also simply a comparison of a value with another value. The order of values from least to greatest is:

  • none
  • null
  • bool
  • number
  • string
  • duration
  • datetime
  • UUID
  • array
  • object
  • geometry
  • bytes
  • record

As a result, all of the following return true.

RETURN [ null > none, true > null, 1 > true, 'a' > 999999999, 1s > 'a', time::now() > 1s, rand::uuid() > time::now(), [] > rand::uuid(), {} > [], (89.0, 89.0) > {}, <bytes>'Aeon' > (89.0, 89.0), person:aeon > <bytes>'Aeon' ];

Being able to compare a value with any other value is what makes SurrealDB’s record range syntax possible. As the least possible value is NONE, a query for the records below that begins with NONE and ends with the .. open range syntax will return everything.

CREATE time_data:['2024-07-23T06:36:56.004Z']; CREATE time_data:['2024-07-24T06:36:56.014Z']; CREATE time_data:['2024-07-25T06:36:56.014Z']; SELECT * FROM time_data:[<datetime>'2024-07-24']..; SELECT * FROM time_data:[NONE]..;

Inside a schema, the keyword any is used to denote any possible value.

DEFINE FIELD anything ON TABLE person TYPE any;

Values and truthiness

Any value is considered to be truthy if it is not NONE, NULL, or a default value for the data type. A data type at its default value is one that is empty, such as an empty string or array or object, or a number set to 0.

The following example shows the result of the array::all() method, which checks to see if all of the items inside an array are truthy or not.

RETURN array::all(["", 1, 2, 3]); // false because of "" RETURN array::all([{}, 1, 2, 3]); // false because of {} RETURN array::all(["SurrealDB", { is_nice_database: true }, 1, 2, 3]); // true

As the ! operator reverses the truthiness of a value, a doubling of this operator can also be used to check for truthiness.

RETURN [ !!"Has a value", !!"", // true, false !!true, !!false, // true, false !!{ is_nice_database: true }, !!{} // true, false ];

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