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ObjectToArray (NoSQL query)

  • מאמר

APPLIES TO: NoSQL

Converts each field/value pair in a JSON object into an element and then returns the set of elements as a JSON array. By default, the array elements contain a new k field for the original field's name and a new v field for the original field's value. These new field names can be further customized.

Syntax

ObjectToArray(<object_expr> [, <string_expr_1>, <string_expr_2>])

Arguments

Description
object_expr An object expression with properties in field/value pairs.
string_expr_1 (Optional) A string expression with a name for the field representing the field portion of the original field/value pair.
string_expr_2 (Optional) A string expression with a name for the field representing the value portion of the original field/value pair.

Return types

An array of elements with two fields, either k and v or custom-named fields.

Examples

This example demonstrates converting a static object to an array of field/value pairs using the default k and v identifiers.

SELECT VALUE
    ObjectToArray({ 
        "a": "12345", 
        "b": "67890"
    })

[
  [
    {
      "k": "a",
      "v": "12345"
    },
    {
      "k": "b",
      "v": "67890"
    }
  ]
]

In this example, the field name is updated to use the name identifier.

SELECT VALUE
    ObjectToArray({ 
        "a": "12345", 
        "b": "67890"
    }, "name")

[
  [
    {
      "name": "a",
      "v": "12345"
    },
    {
      "name": "b",
      "v": "67890"
    }
  ]
]

In this example, the value name is updated to use the value identifier and the field name uses the key identifier.

SELECT VALUE
    ObjectToArray({ 
        "a": "12345", 
        "b": "67890"
    }, "key", "value")

[
  [
    {
      "key": "a",
      "value": "12345"
    },
    {
      "key": "b",
      "value": "67890"
    }
  ]
]

This final example uses an item within an existing container that stores data using fields within a JSON object.

[
  {
    "name": "Witalica helmet",
    "category": "sport-helmets",
    "quantities": {
      "small": 15,
      "medium": 24,
      "large": 2,
      "xlarge": 0
    }
  }
]

In this example, the function is used to break up the object into an array item for each field/value pair.

SELECT
    p.name,
    ObjectToArray(p.quantities, "size", "quantity") AS quantitiesBySize
FROM
    products p
WHERE
    p.category = "sport-helmets"

[
  {
    "name": "Witalica helmet",
    "quantitiesBySize": [
      {
        "size": "small",
        "quantity": 15
      },
      {
        "size": "medium",
        "quantity": 24
      },
      {
        "size": "large",
        "quantity": 2
      },
      {
        "size": "xlarge",
        "quantity": 0
      }
    ]
  }
]

Remarks

  • If the input value isn't a valid object, the result is undefined.

See also