JSON Functions

JSON functions provide functionality for working with JSON (JavaScript Object Notation) data.

Sample Data For Examples

Examples provided with XML functions use the following table structure

TABLE  Customer (
    CustomerId integer PRIMARY KEY,
    CustomerName varchar(25),
    ContactName varchar(25)
    Address varchar(50),
    City varchar(25),
    PostalCode varchar(25),
    Country varchar(25),
);

with Data

CustomerID CustomerName ContactName Address City PostalCode Country

87

Wartian Herkku

Pirkko Koskitalo

Torikatu 38

Oulu

90110

Finland

88

Wellington Importadora

Paula Parente

Rua do Mercado, 12

Resende

08737-363

Brazil

89

White Clover Markets

Karl Jablonski

305 - 14th Ave. S. Suite 3B

Seattle

98128

USA

JSONTOXML

Returns an xml document from JSON.

JSONTOXML(rootElementName, json)

rootElementName is a string, json is in \{clob, blob}. Return value is xml.

The appropriate UTF encoding (8, 16LE. 16BE, 32LE, 32BE) will be detected for JSON blobs. If another encoding is used, see the to_chars function.

The result is always a well-formed XML document.

The mapping to XML uses the following rules:

  • The current element name is initially the rootElementName, and becomes the object value name as the JSON structure is traversed.

  • All element names must be valid xml 1.1 names. Invalid names are fully escaped according to the SQLXML specification.

  • Each object or primitive value will be enclosed in an element with the current name.

  • Unless an array value is the root, it will not be enclosed in an additional element.

  • Null values will be represented by an empty element with the attribute xsi:nil="true"

  • Boolean and numerical value elements will have the attribute xsi:type set to boolean and decimal respectively.

JSON:

Sample JSON to XML for jsonToXml(’person’, x)

{"firstName" : "John" , "children" : [ "Randy", "Judy" ]}

XML:

Sample JSON to XML for jsonToXml(’person’, x)

<?xml version="1.0" ?>
   <person>
      <firstName>John</firstName>
      <children>Randy</children>
      <children>Judy<children>
   </person>

JSON:

Sample JSON to XML for jsonToXml('person', x) with a root array
[{"firstName" : "George" }, { "firstName" : "Jerry" }]

XML (Notice there is an extra "person" wrapping element to keep the XML well-formed):

Sample JSON to XML for jsonToXml(’person’, x) with a root array
<?xml version="1.0" ?>
<person>
  <person>
    <firstName>George</firstName>
  </person>
  <person>
    <firstName>Jerry</firstName>
  </person>
</person>

JSON:

Sample JSON to XML for jsonToXml(’root’, x) with an invalid name
{"/invalid" : "abc" }

XML:

Sample JSON to XML for jsonToXml(’root’, x) with an invalid name
<?xml version="1.0" ?>
<root>
  <_u002F_invalid>abc</_u002F_invalid>
</root>

JSONARRAY

Returns a JSON array.

JSONARRAY(value...)

value is any object convertable to a JSON value. Return value is a clob marked as being valid JSON.

Null values will be included in the result as null literals.

mixed value example

jsonArray('a"b', 1, null, false, {d'2010-11-21'})

Would return

["a\"b",1,null,false,"2010-11-21"]

Using JSONARRAY on a Table

SELECT JSONARRAY(CustomerId, CustomerName)
FROM   Customer c
WHERE  c.CustomerID >= 88;
==========================================================
[88,"Wellington Importadora"]
[89,"White Clover Markets"]

JSONOBJECT

Returns a JSON object.

JSONARRAY(value [as name] ...)

value is any object convertable to a JSON value. Return value is a clob marked as being valid JSON.

Null values will be included in the result as null literals.

If a name is not supplied and the expression is a column reference, the column name will be used otherwise exprN will be used where N is the 1-based index of the value in the JSONARRAY expression.

mixed value example

jsonObject('a"b' as val, 1, null as "null")

Would return

{"val":"a\"b","expr2":1,"null":null}

Using JSONOBJECT on a Table

SELECT JSONOBJECT(CustomerId, CustomerName)
FROM   Customer c
WHERE  c.CustomerID >= 88;
==========================================================
{"CustomerId":88, "CustomerName":"Wellington Importadora"}
{"CustomerId":89, "CustomerName":"White Clover Markets"}

Another example

SELECT JSONOBJECT(JSONOBJECT(CustomerId, CustomerName) as Customer)
FROM   Customer c
WHERE  c.CustomerID >= 88;
==========================================================
{"Customer":{"CustomerId":88, "CustomerName":"Wellington Importadora"}}
{"Customer":{"CustomerId":89, "CustomerName":"White Clover Markets"}}

Another example

SELECT JSONOBJECT(JSONARRAY(CustomerId, CustomerName) as Customer)
FROM   Customer c
WHERE  c.CustomerID >= 88;
==========================================================
{"Customer":[88, "Wellington Importadora"]}
{"Customer":[89, "White Clover Markets"]}

JSONPARSE

Validates and returns a JSON result.

JSONPARSE(value, wellformed)

value is blob with an appropriate JSON binary encoding (UTF-8, UTF-16, or UTF-32) or a clob. wellformed is a boolean indicating that validation should be skipped. Return value is a clob marked as being valid JSON.

A null for either input will return null.

json parse of a simple literal value

jsonParse('{"Customer":{"CustomerId":88, "CustomerName":"Wellington Importadora"}}', true)

JSONARRAY_AGG

creates a JSON array result as a Clob including null value. This is similar to JSONARRAY but aggregates its contents into single object

SELECT JSONARRAY_AGG(JSONOBJECT(CustomerId, CustomerName))
FROM   Customer c
WHERE  c.CustomerID >= 88;
==========================================================
[{"CustomerId":88, "CustomerName":"Wellington Importadora"}, {"CustomerId":89, "CustomerName":"White Clover Markets"}]

You can also wrap array as

SELECT JSONOBJECT(JSONARRAY_AGG(JSONOBJECT(CustomerId as id, CustomerName as name)) as Customer)
FROM   Customer c
WHERE  c.CustomerID >= 88;
==========================================================
{"Customer":[{"id":89,"name":"Wellington Importadora"},{"id":100,"name":"White Clover Markets"}]}

Conversion to JSON

A straight-forward specification compliant conversion is used for converting values into their appropriate JSON document form.

  • null values are included as the null literal.

  • values parsed as JSON or returned from a JSON construction function (JSONPARSE, JSONARRAY, JSONARRAY_AGG) will be directly appended into a JSON result.

  • boolean values are included as true/false literals

  • numeric values are included as their default string conversion - in some circumstances if not a number or +-infinity results are allowed, invalid json may be obtained.

  • string values are included in their escaped/quoted form.

  • binary values are not implicitly convertable to JSON values and require a specific prior to inclusion in JSON.

  • all other values will be included as their string conversion in the appropriate escaped/quoted form.

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