JSON extension

The json extension adds support for JSON objects, including a set of functions for JSON access and manipulation, scanning from, and copying to JSON files. Using this extension, you can interact with JSON files using LOAD FROM, COPY FROM, and COPY TO, similar to how you would with CSV files.

See our YouTube video for a walkthrough on how to use the JSON extension:

Usage

INSTALL json;
LOAD json;

Example dataset

Let’s look at an example dataset to demonstrate how the JSON extension can be used. We have 3 JSON files that contain information about patients and their medical conditions. The files are organized into two node files (patient.json and condition.json) and one relationship file (has_condition.json).

[
    {
        "p_id": "p1",
        "name": "Gregory",
        "info": {
            "height": 1.81,
            "weight": 75.5,
            "age": 35,
            "insurance_provider": [
                {
                    "type": "health",
                    "name": "Blue Cross Blue Shield",
                    "policy_number": "1536425345"
                },
                {
                    "type": "dental",
                    "name": "Cigna dental",
                    "policy_number": "745332412"
                }
            ]
        }
    },
    {
        "p_id": "p2",
        "name": "Alicia",
        "info": {
            "height": 1.65,
            "weight": 60.1,
            "age": 28,
            "insurance_provider": [
                {
                    "type": "health",
                    "name": "Aetna",
                    "policy_number": "9876543210"
                }
            ]
        }
    },
    {
        "p_id": "p3",
        "name": "Rebecca"
    }
]

[
    {
        "c_id": "c1",
        "name": "Diabetes (Type 1)",
        "description": "Diabetes is a chronic condition where the body can't properly regulate blood sugar levels, either due to insufficient insulin production or ineffective use of insulin, leading to potential health complications."
    },
    {
        "c_id": "c2",
        "name": "Asthma",
        "description": "Asthma is a chronic condition that affects the airways in your lungs, causing inflammation and narrowing of the airways. This can lead to difficulty breathing, coughing, and other symptoms."
    },
    {
        "c_id": "c3",
        "name": "Allergic Rhinitis",
        "description": "Allergic rhinitis, also known as hay fever, is a condition where your immune system overreacts to allergens like pollen, mold, or pet dander, causing symptoms like sneezing, congestion, and nasal itching."
    },
    {
        "c_id": "c4",
        "name": "Migraine",
        "description": "Migraine is a common neurological condition characterized by recurring headaches with associated symptoms like nausea, vomiting, and sensitivity to light or sound. It can be severe and disabling, impacting daily life."
    }
]

[
    {
        "from": "p1",
        "to": "c1",
        "since": 2019
    },
    {
        "from": "p1",
        "to": "c2",
        "since": 2015
    },
    {
        "from": "p2",
        "to": "c1",
        "since": 2022
    },
    {
        "from": "p2",
        "to": "c4",
        "since": 2020
    }
]

In the following sections, we will first scan the JSON files to query their contents in Cypher, and then proceed to copy the JSON data and construct a graph.

Scan the JSON file

LOAD FROM is a Cypher query that scans a file or object element by element, but doesn’t actually move the data into a Kuzu table.

Because the JSON format contains simple data types without type information, the structure will be inferred. To declare type information explicitly, you can use LOAD WITH HEADERS like you would for CSV files.

To scan the file above, you can do the following:

LOAD FROM 'patient.json' RETURN *;

┌────────┬─────────┬──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ p_id   │ name    │ info                                                                                                                                                                                                     │
│ STRING │ STRING  │ STRUCT(height DOUBLE, weight DOUBLE, age UINT8, insurance_provider STRUCT(type STRING, name STRING, policy_number STRING)[])                                                                             │
├────────┼─────────┼──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ p1     │ Gregory │ {height: 1.810000, weight: 75.500000, age: 35, insurance_provider: [{type: health, name: Blue Cross Blue Shield, policy_number: 1536425345},{type: dental, name: Cigna dental, policy_number: 7453324... │
│ p2     │ Alicia  │ {height: 1.650000, weight: 60.100000, age: 28, insurance_provider: [{type: health, name: Aetna, policy_number: 9876543210},{type: vision, name: VSP, policy_number: 1784567890}]}                        │
│ p3     │ Rebecca │ {height: 1.780000, weight: , age: 23, insurance_provider: [{type: health, name: Blue Cross Blue Shield, policy_number: 5678901234}]}                                                                     │
└────────┴─────────┴──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

Because info is a nested object, its type in Kuzu is inferred as a STRUCT that itself contains other types, like DOUBLE, UINT8, STRING, and STRUCT.

Missing keys

Missing keys, i.e., keys that are present in one JSON blob but not in another, are returned as the default/empty value for the type. To test this, let’s run another query to get the name, age, height, weight and insurance provider of all patients:

LOAD FROM 'patient.json'
RETURN name, info.age, info.height, info.weight, info.insurance_provider;

┌─────────┬──────────────────────────┬─────────────────────────────┬─────────────────────────────┬─────────────────────────────────────────────────────────────────┐
│ name    │ STRUCT_EXTRACT(info,age) │ STRUCT_EXTRACT(info,height) │ STRUCT_EXTRACT(info,weight) │ STRUCT_EXTRACT(info,insurance_provider)                         │
│ STRING  │ UINT8                    │ DOUBLE                      │ DOUBLE                      │ STRUCT(type STRING, name STRING, policy_number STRING)[]        │
├─────────┼──────────────────────────┼─────────────────────────────┼─────────────────────────────┼─────────────────────────────────────────────────────────────────┤
│ Gregory │ 35                       │ 1.810000                    │ 75.500000                   │ [{type: health, name: Blue Cross Blue Shield, policy_number:... │
│ Alicia  │ 28                       │ 1.650000                    │ 60.100000                   │ [{type: health, name: Aetna, policy_number: 9876543210}]        │
│ Rebecca │ 0                        │ 0.000000                    │ 0.000000                    │ []                                                              │
└─────────┴──────────────────────────┴─────────────────────────────┴─────────────────────────────┴─────────────────────────────────────────────────────────────────┘

As can be seen, the patient Rebecca is new in the system and is missing her information fields:

age is set to the default value of 0 for UINT8
height and weight are set to the default value of 0.0 for DOUBLE
insurance_provider is set to an empty array []

Enforcing types

You can enforce explicit data types during scanning by using the LOAD WITH HEADERS feature.

Example:

LOAD WITH HEADERS (
    p_id STRING,
    name STRING,
    info STRUCT(
        height FLOAT,
        weight FLOAT,
        age UINT8,
        insurance_provider STRUCT(
            type STRING,
            name STRING,
            policy_number STRING
        )[]
    )
)
FROM 'patient.json'
RETURN name, info.height, info.weight;

We can see that the types inside the info STRUCT are now FLOAT rather than DOUBLE.

┌─────────┬─────────────────────────────┬─────────────────────────────┐
│ name    │ STRUCT_EXTRACT(info,height) │ STRUCT_EXTRACT(info,weight) │
│ STRING  │ FLOAT                       │ FLOAT                       │
├─────────┼─────────────────────────────┼─────────────────────────────┤
│ Gregory │ 1.810000                    │ 75.500000                   │
│ Alicia  │ 1.650000                    │ 60.099998                   │
│ Rebecca │ 0.000000                    │ 0.000000                    │
└─────────┴─────────────────────────────┴─────────────────────────────┘

Optional parameters

The following optional parameters are supported:

Name	Description
`maximum_depth`	Default value is `10`. Used by the type inference system to determine how “deep” into the JSON document to go to infer types.
`sample_size`	Default value `2048`. Used by the type inference system to determine the number of elements used to infer the JSON type.

Copy JSON files to a table

The COPY FROM statement allows you to copy data from a JSON file into a node or relationship table in Kuzu. In this section, we will walk through the example dataset shown above and build a graph from the JSON data.

Copy to node tables

First, start by defining a node table schema that conforms to the JSON structure. For nested fields, we declare a STRUCT where necessary.

Example:

CREATE NODE TABLE IF NOT EXISTS Patient(
    p_id STRING,
    name STRING,
    info STRUCT(
        height FLOAT,
        weight FLOAT,
        age UINT8,
        insurance_provider STRUCT(
            type STRING,
            name STRING,
            policy_number STRING
        )[]
    ),
    PRIMARY KEY (p_id)
);

The syntax STRUCT( ... )[] with the square braces at the end represents an array of STRUCTs.

You can then use a COPY FROM statement to directly copy the contents of the JSON file into the node table.

COPY Patient FROM 'patient.json';

Similarly, we can define the node table for the patients’ medical conditions.

CREATE NODE TABLE IF NOT EXISTS Condition(
    c_id STRING,
    name STRING,
    description STRING,
    PRIMARY KEY (c_id)
);

And copy the contents of condition.json to the node table as follows:

COPY Condition FROM 'condition.json';

Copy to relationship tables

To copy from a JSON file to a relationship table, the file must contain the "from" and "to" keys.

In the example dataset for has_condition.json, we have these keys defined:

[
    {
        "from": "p1",
        "to": "c1",
        "since": 2019
    },
    {
        "from": "p1",
        "to": "c2",
        "since": 2015
    },
    ...
]

Any other keys that are not "from" or "to" are treated as relationship properties.

Let’s create a relationship table schema:

CREATE REL TABLE IF NOT EXISTS HAS_CONDITION(
    FROM Patient TO Condition,
    since UINT16
)

The has_condition.json file can then directly be copied into the relationship table that was just created.

COPY HAS_CONDITION FROM 'has_condition.json';

We obtain the following graph:

Any nested fields are ingested into the graph as STRUCTs. We can query on these nested fields as shown below:

MATCH (p:Patient)-[:HAS_CONDITION]->(c:Condition)
WHERE c.name = "Diabetes (Type 1)"
WITH
    p.name AS name,
    p.info.age AS age,
    c.name AS condition,
    p.info.insurance_provider AS ip
UNWIND ip AS provider
WITH name, age, provider, condition
WHERE provider.type = "health"
RETURN name, age, condition, provider.name AS health_insurance_provider;

┌─────────┬───────┬───────────────────┬───────────────────────────┐
│ name    │ age   │ condition         │ health_insurance_provider │
│ STRING  │ UINT8 │ STRING            │ STRING                    │
├─────────┼───────┼───────────────────┼───────────────────────────┤
│ Gregory │ 35    │ Diabetes (Type 1) │ Blue Cross Blue Shield    │
│ Alicia  │ 28    │ Diabetes (Type 1) │ Aetna                     │
└─────────┴───────┴───────────────────┴───────────────────────────┘

Note how the UNWIND clause was used to obtain individual records of the insurance providers for each patient.

`UNWIND` JSON arrays

In the above example, we have useful information about insurance providers that could also be used to capture the relationships between patients and their insurance providers.

Let’s model this using a new node table, InsuranceProvider, and a new relationship table HAS_PROVIDER.

CREATE NODE TABLE IF NOT EXISTS InsuranceProvider(
    name STRING,
    type STRING,
    PRIMARY KEY (name)
)

CREATE REL TABLE IF NOT EXISTS HAS_PROVIDER(
    FROM Patient TO InsuranceProvider,
    policy_number STRING
)

We can then UNWIND the insurance providers for each patient, obtain distinct providers, and then pass these results via a subquery to COPY FROM.

COPY InsuranceProvider FROM (
    LOAD FROM 'patient.json'
    WITH info.insurance_provider AS ip
    UNWIND ip AS provider
    RETURN DISTINCT
        provider.name AS name,
        provider.type AS type
);

Let’s break down the above query step by step:

The outer COPY FROM expects the result from the inner LOAD FROM
The info STRUCT from patient.json is passed to UNWIND so that we can obtain individual providers for each patient
A DISTINCT clause is used when returning the results of the subquery because the name of a provider is the primary key of the InsuranceProvider node table per the schema created above (we cannot have duplicate values for primary keys).

We can do a similar sequence of steps to copy relationships from patient.json as follows:

COPY HAS_PROVIDER FROM (
    LOAD FROM 'patient.json'
    WITH p_id, info.insurance_provider AS ip
    UNWIND ip AS provider
    RETURN
        p_id,
        provider.name AS name,
        provider.policy_number AS policy_number
);

In this case, we didn’t alias the first two entries to from and to like we did when copying from the has_condition.json file above. This is because the COPY FROM query is looking for the first two columns in the result as the FROM and the TO columns in the relationship, similar to how it’s done in CSV.

We now obtain the following graph:

Copy query results to JSON files

Once you have the data in a graph, you can begin querying it in Cypher. You can use the COPY TO statement to write the results of a query to a JSON file. Any query results of the type STRUCT will be written as nested JSON. Two examples are shown below.

Example 1
Example 2

Say you want to write health insurance provider information and patient names for patients with the condition “Migraine” to a JSON file named patient_providers.json.

COPY (
    MATCH (p:Patient)-[:HAS_CONDITION]->(c:Condition)
    WHERE c.name = "Migraine"
    WITH
        p.name AS name,
        p.info.age AS age,
        c.name AS condition,
        p.info.insurance_provider AS ip
    UNWIND ip AS provider
    WITH name, age, provider, condition
    WHERE provider.type = "health"
    RETURN name, age, condition, provider
) TO 'patient_providers.json';

The output JSON would look like this:

[
    {
        "name": "Alicia",
        "age": 28,
        "condition": "Migraine",
        "provider": {
            "type": "health",
            "name": "Aetna",
            "policy_number": "9876543210"
        }
    }
]

Say we want to write the name of the condition and a list of patient names who have the condition and have health insurance to a JSON file named patients_with_condition.json. This is how we would query the graph:

COPY (
    MATCH (c:Condition)<-[:HAS_CONDITION]-(a:Patient)-[:HAS_PROVIDER]->(pr:InsuranceProvider)
    WHERE c.name = 'Diabetes (Type 1)' AND pr.type = 'health'
    RETURN
        c.name AS condition,
        COLLECT(a.name) AS patients;
) TO 'patients_with_condition.json';

The output JSON would look like this:

[
    {
        "condition": "Diabetes (Type 1)",
        "patients": [
            "Gregory",
            "Alicia"
        ]
    }
]

Takeaways

When using the json extension, keep in mind the following considerations when copying data to Kuzu tables:

The order of the keys in the JSON file doesn’t need to match the order of the columns defined in the schema. Only the names need to match.
If directly copying from a JSON file to a relationship table, there need to be keys named from and to in the file whose values point to the primary key values of the underlying node tables.
You can combine LOAD FROM subqueries with COPY FROM to have more control over the subset of JSON data being copied, as well as dynamically transform your data via UNWIND or DISTINCT clauses, so it’s not necessary to write your relationships to an intermediate file prior to using COPY.

JSON data type

Using the json extension, you can model and store properties as JSON natively via the JSON logical type, which is interpreted and parsed as JSON, rather than as a string.

The following example creates a node table Person with a JSON column description, it then creates two JSON objects in this column using the to_json function, and outputs them.

Example:

INSTALL json;
LOAD json;

CREATE NODE TABLE Person (id INT64 PRIMARY KEY, description JSON);
CREATE (p:Person {id: 20, description: to_json({height: 52, age: 32, scores: [1,2,5]})});
CREATE (p:Person {id: 40, description: to_json({age: 55, scores: [1,32,5,null], name: 'dan'})});
MATCH (p:Person) RETURN p.*;

┌───────┬────────────────────────────────────────────────┐
│ p.id  │ p.description                                  │
│ INT64 │ json                                           │
├───────┼────────────────────────────────────────────────┤
│ 20    │ {"height":52,"age":32,"scores":[1,2,5]}        │
│ 40    │ {"age":55,"scores":[1,32,5,null],"name":"dan"} │
└───────┴────────────────────────────────────────────────┘

You can then query on these properties as follows:

MATCH (p:Person)
WHERE json_extract(p.description, 'age') < 50
RETURN p.id AS id, json_extract(p.description, 'age') AS age;

┌───────┬──────┐
│ id    │ age  │
│ INT64 │ json │
├───────┼──────┤
│ 20    │ 32   │
└───────┴──────┘

JSON functions

This section lists the built-in functions that operate on the JSON data type within Kuzu.

`to_json(value:ANY) -> JSON`

Converts value of any Kuzu type to JSON.

Example 1:

RETURN to_json('{"name": "Gregory"}') AS person;

┌────────────────────┐
│ person             │
│ json               │
├────────────────────┤
│ {"name":"Gregory"} │
└────────────────────┘

Example 2:

RETURN to_json([1,2,3]) AS json_array;

┌────────────┐
│ json_array │
│ json       │
├────────────┤
│ [1,2,3]    │
└────────────┘

Example 3:

RETURN to_json('Alicia') AS simple_string;

┌───────────────┐
│ simple_string │
│ json          │
├───────────────┤
│ "Alicia"      │
└───────────────┘

`array_to_json(value:ARRAY) -> JSON`

Alias for to_json that only accepts ARRAY.

`row_to_json(value:LIST) -> JSON`

Alias for to_json that only accepts LIST.

`cast(value:ANY AS JSON) -> JSON`

`cast(value:ANY, "JSON") -> ANY`

Syntax sugar for to_json.

Example:

RETURN cast('{"name": "Alicia", "age": 28}' AS JSON);

┌───────────────────────────────────────────┐
│ CAST({"name": "Alicia", "age": 28}, json) │
│ json                                      │
├───────────────────────────────────────────┤
│ {"name":"Alicia","age":28}                │
└───────────────────────────────────────────┘

`json_object(key:STRING, value:ANY, ...) -> JSON`

Create a JSON object from any number of key, value pairs.

Example 1:

RETURN json_object("name", "Alicia");

┌──────────────────────────┐
│ json_object(name,Alicia) │
│ json                     │
├──────────────────────────┤
│ {"name":"Alicia"}        │
└──────────────────────────┘

Example 2:

RETURN json_object("name", "Alicia", "age", 28);

┌─────────────────────────────────┐
│ json_object(name,Alicia,age,28) │
│ json                            │
├─────────────────────────────────┤
│ {"name":"Alicia","age":28}      │
└─────────────────────────────────┘

`json_array(value:ANY, ...) -> JSON`

Create an array of JSON objects. Each argument is converted into a JSON object.

Example:

RETURN json_array("Alicia", "25", NULL);

┌────────────────────────┐
│ json_array(Alicia,25,) │
│ json                   │
├────────────────────────┤
│ ["Alicia","25",null]   │
└────────────────────────┘

`json_merge_patch(json1:JSON, json2:JSON) -> JSON`

Merges two JSON objects, following the RFC 7386 specification.

Example 1:

RETURN json_merge_patch('{"name": "Alicia"}', '{"age": 28}');

┌──────────────────────────────────────────────────┐
│ json_merge_patch({"name": "Alicia"},{"age": 28}) │
│ json                                             │
├──────────────────────────────────────────────────┤
│ {"name":"Alicia","age":28}                       │
└──────────────────────────────────────────────────┘

Example 2:

Merging with a NULL argument results in a NULL output.

RETURN json_merge_patch("3", NULL);

┌──────────────────────┐
│ json_merge_patch(3,) │
│ json                 │
├──────────────────────┤
│                      │
└──────────────────────┘

`json_extract(json:JSON, path:STRING) -> JSON`

`json_extract(json:JSON, path:INTEGER) -> JSON`

`json_extract(json:JSON, path:LIST) -> LIST[JSON]`

Extracts JSON from json at the given path, where path is an index into the JSON object. Refer to the examples to see how path is interpreted. Invalid paths return an empty JSON.

Example 1:

A single string path.

RETURN
    json_extract(
        '{"Software": {"Database": ["duck", "kuzu"]}}',
        'Software/Database/1'
    ) AS extracted;

┌───────────┐
│ extracted │
│ json      │
├───────────┤
│ "kuzu"    │
└───────────┘

Example 2:

A list of string paths.

RETURN
    json_extract(
        '{"Software": {"Database": ["duck", "kuzu"]}}',
        ['Software/Database/1', 'Software/Database/0']
    ) AS extracted;

┌─────────────────┐
│ extracted       │
│ json[]          │
├─────────────────┤
│ ["kuzu","duck"] │
└─────────────────┘

Example 3:

An integer path that represents the index of the item in the JSON array we want to extract.

RETURN json_extract('[1, 2, 42]', 2) AS nums;

┌──────┐
│ nums │
│ json │
├──────┤
│ 42   │
└──────┘

Extracting from an empty path results in an empty JSON:

RETURN
    json_extract(
        '{"Software": {"Database": ["duck", "kuzu"]}}',
        ""
    ) AS extracted;

┌───────────┐
│ extracted │
│ json      │
├───────────┤
│           │
└───────────┘

`json_array_length(json:JSON) -> UINT32`

If the json is a JSON array, returns its length, otherwise returns 0.

Example 1:

RETURN json_array_length('["1", "1", "4", null]') AS len;

┌────────┐
│ len    │
│ UINT32 │
├────────┤
│ 4      │
└────────┘

Example 2:

Trying to compute the length of a JSON array containing a null value results in a length of zero, as this isn’t a valid JSON array.

RETURN json_array_length('{"kuzu": ["1", "1", "4", null]}') AS len;

┌────────┐
│ len    │
│ UINT32 │
├────────┤
│ 0      │
└────────┘

`json_contains(haystack:JSON, needle:JSON) -> BOOL`

Returns true if needle is contained in haystack. Both parameters are of JSON. needle can be a numeric value or a string wrapped in double quotes.

Example 1:

RETURN JSON_CONTAINS('{"name": "Alicia"}', '"Alicia"') AS found_name;

┌────────────┐
│ found_name │
│ BOOL       │
├────────────┤
│ True       │
└────────────┘

Example 2:

RETURN JSON_CONTAINS('{"age": 28}', '28') AS found_age;

┌───────────┐
│ found_age │
│ BOOL      │
├───────────┤
│ True      │
└───────────┘

`json_keys(json:JSON) -> STRING[]`

Returns keys of the root json object. If the root is not a JSON object, returns an empty list.

Example:

RETURN
    json_keys(
        '{ "family": "anatidae", "species": [ "duck", "goose", "swan", null ] }'
    ) AS keys;

┌──────────────────┐
│ keys             │
│ STRING[]         │
├──────────────────┤
│ [family,species] │
└──────────────────┘

`json_structure(json:JSON) -> STRING`

Returns the type structure of the json in Kuzu type notation. Integer widths are automatically inferred from input values.

Example:

RETURN
    json_structure(
        '[{"a": -1, "b": [1000, 2000, 3000]}, {"a": 2, "c": "hi"}]'
    ) AS structure;

┌─────────────────────────────────────────┐
│ structure                               │
│ STRING                                  │
├─────────────────────────────────────────┤
│ STRUCT(a INT16, b UINT16[], c STRING)[] │
└─────────────────────────────────────────┘

`json_valid(json:JSON) -> BOOL`

Determines whether the provided json is valid.

Example 1:

RETURN json_valid('{"name": "Alicia", "age": 28}') AS is_valid;

┌──────────┐
│ is_valid │
│ BOOL     │
├──────────┤
│ True     │
└──────────┘

Example 2:

RETURN json_valid('"name": "Alicia", "age": 28') AS is_valid;

┌──────────┐
│ is_valid │
│ BOOL     │
├──────────┤
│ False    │
└──────────┘

`json(json:JSON) -> JSON`

Parses and minifies the input json.

Example:

UNWIND
    [
        '[   {"a":  [1],     "b": 2,"c": 1}, 1,    5, 9]', '[1, 2, 3]', '"ab"'
    ] AS arr
RETURN
    json(arr);

┌───────────────────────────────┐
│ json(arr)                     │
│ json                          │
├───────────────────────────────┤
│ [{"a":[1],"b":2,"c":1},1,5,9] │
│ [1,2,3]                       │
│ "ab"                          │
└───────────────────────────────┘

JSON extension

Usage

Example dataset

Scan the JSON file

Missing keys

Enforcing types

Optional parameters

Copy JSON files to a table

Copy to node tables

Copy to relationship tables

UNWIND JSON arrays

Copy query results to JSON files

Takeaways

JSON data type

JSON functions

to_json(value:ANY) -> JSON

array_to_json(value:ARRAY) -> JSON

row_to_json(value:LIST) -> JSON

cast(value:ANY AS JSON) -> JSON

cast(value:ANY, "JSON") -> ANY

json_object(key:STRING, value:ANY, ...) -> JSON

json_array(value:ANY, ...) -> JSON

json_merge_patch(json1:JSON, json2:JSON) -> JSON

json_extract(json:JSON, path:STRING) -> JSON

json_extract(json:JSON, path:INTEGER) -> JSON

json_extract(json:JSON, path:LIST) -> LIST[JSON]

json_array_length(json:JSON) -> UINT32

json_contains(haystack:JSON, needle:JSON) -> BOOL

json_keys(json:JSON) -> STRING[]

json_structure(json:JSON) -> STRING

json_valid(json:JSON) -> BOOL

json(json:JSON) -> JSON

`UNWIND` JSON arrays

`to_json(value:ANY) -> JSON`

`array_to_json(value:ARRAY) -> JSON`

`row_to_json(value:LIST) -> JSON`

`cast(value:ANY AS JSON) -> JSON`

`cast(value:ANY, "JSON") -> ANY`

`json_object(key:STRING, value:ANY, ...) -> JSON`

`json_array(value:ANY, ...) -> JSON`

`json_merge_patch(json1:JSON, json2:JSON) -> JSON`

`json_extract(json:JSON, path:STRING) -> JSON`

`json_extract(json:JSON, path:INTEGER) -> JSON`

`json_extract(json:JSON, path:LIST) -> LIST[JSON]`

`json_array_length(json:JSON) -> UINT32`

`json_contains(haystack:JSON, needle:JSON) -> BOOL`

`json_keys(json:JSON) -> STRING[]`

`json_structure(json:JSON) -> STRING`

`json_valid(json:JSON) -> BOOL`

`json(json:JSON) -> JSON`