20.6 DOES_EXIST Function

This function determines whether the given path points to an existing value.

Syntax

APEX_JSON.DOES_EXIST (
   p_path             IN VARCHAR2,
   p0                 IN VARCHAR2 DEFAULT NULL,
   p1                 IN VARCHAR2 DEFAULT NULL,
   p2                 IN VARCHAR2 DEFAULT NULL,
   p3                 IN VARCHAR2 DEFAULT NULL,
   p4                 IN VARCHAR2 DEFAULT NULL,
   p_values           IN t_values DEFAULT g_values ) 
RETURN BOOLEAN;

Parameters

Table 20-1 DOES_EXIST Function Parameters

Parameter	Description
`p_path`	Index into `p_values`.
`p[0-4]`	Each %N in `p_path` is replaced by `pN` and every i-th %s or %d is replaced by the `p[i-1]`.
`p_values`	Parsed JSON members. The default is `g_values`.

Returns

Table 20-2 DOES_EXIST Function Returns

Return	Description
`TRUE`	Given path points to an existing value.
`FALSE`	Given path does not point to an existing value

Example

This example parses a JSON string and prints whether it contains values under a path.

DECLARE 
    j apex_json.t_values; 
BEGIN 
    apex_json.parse(j, '{ "items": [ 1, 2, { "foo": true } ] }'); 
    if apex_json.does_exist(p_path => 'items[%d].foo', p0 => 3, p_values => 
j) then 
        dbms_output.put_line('found items[3].foo'); 
    end if; 
END;

Parent topic: APEX_JSON