MD5_HIDDEN Function

Use this function for lost update detection. Lost update detection ensures data integrity in applications where data can be accessed concurrently.

This function produces a hidden form field with a MD5 checksum as value which is based on up to 50 inputs. APEX_ITEM.MD5_HIDDEN also produces an MD5 checksum using Oracle database DBMS_CRYPTO:

UTL_RAW.CAST_TO_RAW(DBMS_CRYPTO.MD5())

An MD5 checksum provides data integrity through hashing and sequencing to ensure that data is not altered or stolen as it is transmitted over a network

Syntax

APEX_ITEM.MD5_HIDDEN(
    p_idx       IN    NUMBER,
    p_value01   IN    VARCHAR2 DEFAULT NULL,
    p_value02   IN    VARCHAR2 DEFAULT NULL,
    p_value03   IN    VARCHAR2 DEFAULT NULL,
    ...
    p_value50   IN    VARCHAR2 DEFAULT NULL,
    p_col_sep   IN    VARCHAR2 DEFAULT '|',
    p_item_id   IN    VARCHAR2 DEFAULT NULL)
    RETURN VARCHAR2;

Parameters

Table 21-7 MD5_HIDDEN Parameters

Parameter	Description
`p_idx`	Indicates the form element to be generated. For example, 1 equals `F01` and 2 equals `F02`. Typically the `p_idx` parameter is constant for a given column
`p_value01` ... `p_value50`	Fifty available inputs. Parameters not supplied default to NULL
`p_col_sep`	String used to separate `p_value` inputs. Defaults to the pipe symbol (\|)
`p_item_id`	ID of the HTML form item

Example

The p_idx parameter specifies the FXX form element to be generated. In the following example, 7 generates F07. Also note that an HTML hidden form element is generated.

SELECT APEX_ITEM.MD5_HIDDEN(7,ename,job,sal)md5_h, ename, job, sal 
FROM emp