Supported Data Types

Kùzu supports a set of primitive and nested data types both for node and relationship properties as well as for forming expressions whose outputs are in these data types. See expressions and functions for the supported operators and functions on these data types to form expressions.

Primitive Data Types

STRING Data Type

UTF-8 encoding is supported for STRING data type.

RETURN 'Зарегистрируйтесь, σπαθιοῦ, Yen [jɛn], kΩ' AS str;

Output:

---------------------------------------------
| str                                       |
---------------------------------------------
| Зарегистрируйтесь, σπαθιοῦ, Yen [jɛn], kΩ |
---------------------------------------------

VAR-LIST Data Type

VAR-List is a nested data type to store a list of arbitrary number of values of the same type. Values in a list can themselves be nested lists. A few examples:

UNWIND [[1,2], [3], [4, 5]] AS x
RETURN x;
output:
---------
| x     |
---------
| [1,2] |
---------
| [3]   |
---------
| [4,5] |
---------

UNWIND [[1,2], [3], [4, 5]] AS x 
UNWIND x as y 
RETURN y;
output:
-----
| y |
-----
| 1 |
-----
| 2 |
-----
| 3 |
-----
| 4 |
-----
| 5 |
-----

FIXED-LIST Data Type (TENSOR)

FIXED-List is a nested data type to store a list of fixed number of values of the same type. Values in FIXED-LIST must have the same type and should be numerical types.

Temporal Data Types

Kùzu supports three temporal data types: Date, Timestamp, and Interval. We give information about each data type below.

DATE

Dates are specified in ISO 8601 format (YYYY-MM-DD). You need to cast strings to dates using the date(...) function to construct literal dates. Below is an example:

RETURN date('2022-06-06') as x;
output:
--------------
| x          |
--------------
| 2022-06-06 |
--------------

TIMESTAMP

Timestamps combine date and a time (hour, minute, second, millisecond) and are formatted according to the ISO 8601 format (YYYY-MM-DD hh:mm:ss[.zzzzzz][+-TT[:tt]]), which specifies the date (YYYY-MM-DD), time (hh:mm:ss[.zzzzzz]) and a time offset [+-TT[:tt]]. Only the Date part is mandatory. If time is specified, then the milliesecond [.zzzzzz] part and the time offset are optional. Similar to dates, you need to cast strings to timestamps using the timestamp(...) function to construct literal timestamps. Below is an example:

RETURN timestamp("1970-01-01 00:00:00.004666-10") as x;
output:
------------------------------
| x                          |
------------------------------
| 1970-01-01 10:00:00.004666 |
------------------------------

Interval

An interval consists of multiple date parts and represents the total time length of these date parts. Kùzu follows DuckDB’s implementation for the format of specifying intervals. See DuckDB’s documentation for details. Similar to dates and timestamps, you need to cast strings to intervals to specify interval literals

RETURN interval("1 year 2 days") as x;
output:
-----------------
| x             |
-----------------
| 1 year 2 days |
-----------------

NULL Values

NULLs are special values to represent unknown/unavailable data. Every node/relationship property or result of any expression can be NULL in addition to the non-NULL domain of values they can take. For example, boolean expression can be true/false or NULL. Outputs of boolean operators where any of the operands are NULL is NULL. The NULL (in any of its case variations, such as Null or null) can be used to specify a null literal. Below ares some examples:

RETURN 3 = 3;
output:
---------
| 3 = 3 |
---------
| True  |
---------

RETURN 3 = null;
output:
------------
| 3 = null |
------------
|          |
------------

RETURN null = null;
output:
---------------
| null = null |
---------------
|             |
---------------

Kùzu’s CLI returns an empty cell to indicate nulls.