25.6 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 25-1 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 25-2 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;