This procedure writes an open curly bracket symbol as follows:
{
Syntax
APEX_JSON.OPEN_OBJECT (
    p_name     IN VARCHAR2 DEFAULT NULL );
Parameters
Table 15-24 OPEN_OBJECT Procedure Parameters
| Parameter | Description | 
|---|---|
| 
 | If not null, write an object attribute name and colon before the opening brace. | 
Example
This example performs a write { "obj": { "obj-attr": "value" }}.
BEGIN
  apex_json.open_object; -- {
  apex_json.open_object('obj'); -- "obj": {
  apex_json.write('obj-attr', 'value'); -- "obj-attr": "value"
  apex_json.close_all; -- }}
END;