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Oracle® Application Express API Reference
Release 3.2
E12510-01
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10 APEX_PLSQL_JOB

You can use APEX_PLSQL_JOB package to run PL/SQL code in the background of your application. This is an effective approach for managing long running operations that do not need to complete for a user to continue working with your application.

Topics in this section include:


JOBS_ARE_ENABLED Function

Call this function to determine whether or not the database is currently in a mode that supports submitting jobs to the APEX_PLSQL_JOB package.

Syntax

APEX_PLSQL_JOB.JOBS_ARE_ENABLED
RETURN BOOLEAN;

Parameters

None.

Example

The following example shows how to use the JOBS_ARE_ENABLED function. In the example, if the function returns TRUE the message 'Jobs are enabled on this database instance' is displayed, otherwise the message 'Jobs are not enabled on this database instance' is displayed.

BEGIN
    IF APEX_PLSQL_JOB.JOBS_ARE_ENABLED THEN
        HTP.P('Jobs are enabled on this database instance.');
    ELSE
        HTP.P('Jobs are not enabled on this database instance.');
    END IF;
END;

PURGE_PROCESS Procedure

Call this procedure to clean up submitted jobs. Submitted jobs stay in the APEX_PLSQL_JOBS view until either Oracle Application Express cleans out those records, or you call PURGE_PROCESS to manually remove them.

Syntax

APEX_PLSQL_JOB.PURGE_PROCESS (
    p_job IN NUMBER);

Parameters

Table 10-1 describes the parameters available in the PURGE_PROCESS procedure.

Table 10-1 PURGE_PROCESS Parameters

Parameter Description

p_job

The job number that identifies the submitted job you wish to purge.


Example

The following example shows how to use the PURGE_PROCESS procedure to purge the submitted job identified by a job number of 161. You could also choose to purge all or some of the current submitted jobs by referencing the APEX_PLSQL_JOBS view.

BEGIN
    APEX_PLSQL_JOB.PURGE_PROCESS(
        p_job => 161);
END;

SUBMIT_PROCESS Function

Use this procedure to submit background PL/SQL. This procedure returns a unique job number. Because you can use this job number as a reference point for other procedures and functions in this package, it may be useful to store it in your own schema.

Syntax

APEX_PLSQL_JOB.SUBMIT_PROCESS (
    p_sql IN VARCHAR2,
    p_when IN DATE DEFAULT SYSDATE,
    p_status IN VARCHAR2 DEFAULT 'PENDING')
RETURN NUMBER;

Parameters

Table 10-2 describes the parameters available in the SUBMIT_PROCESS function.

Table 10-2 SUBMIT_PROCESS Parameters

Parameter Description

p_sql

The process you wish to run in your job. This can be any valid anonymous block, for example:

'BEGIN <your code> END;'
or
'DECLARE <your declaration> 
BEGIN <your code> END;'

p_when

When you want to run it. The default is SYSDATE which means the job will run as soon as possible. You can also set the job to run in the future, for example:

sysdate + 1 - The job will run in 1 days time.

sysdate + (1/24) - The job will run in 1 hours time.

sysdate + (10/24/60) - The job will run in 10 minutes time.

p_status

Plain text status information for this job.


Example

The following example shows how to use the SUBMIT_PROCESS function to submit a background process that will start as soon as possible.

DECLARE
    l_sql VARCHAR2(4000);
    l_job NUMBER;
BEGIN
    l_sql := 'BEGIN MY_PACKAGE.MY_PROCESS; END;';
    l_job := APEX_PLSQL_JOB.SUBMIT_PROCESS(
        p_sql => l_sql,
        p_status => 'Background process submitted');
    --store l_job for later reference
END;

TIME_ELAPSED Function

Use this function to determine how much time has elapsed since the job was submitted.

Syntax

APEX_PLSQL_JOB.TIME_ELAPSED(
    p_job IN NUMBER)
RETURN NUMBER;

Parameters

Table 10-3 describes the parameters available in the TIME_ELAPSED function.

Table 10-3 TIME_ELAPSED Parameters

Parameter Description

p_job

The job ID for the job you wish to see how long since it was submitted.


Example

The following example shows how to use the TIME_ELAPSED function to get the time elapsed for the submitted job identified by the job number 161.

DECLARE
    l_time NUMBER;
BEGIN
    l_time := APEX_PLSQL_JOB.TIME_ELAPSED(p_job => 161);
END;

UPDATE_JOB_STATUS Procedure

Call this procedure to update the status of the currently running job. This procedure is most effective when called from the submitted PL/SQL.

Syntax

APEX_PLSQL_JOB.UPDATE_JOB_STATUS (
    p_job IN NUMBER,
    p_status IN VARCHAR2);

Parameters

Table 10-4 describes the parameters available in the UPDATE_JOB_STATUS procedure.

Table 10-4 UPDATE_JOB_STATUS Parameters

Parameter Description

p_job

Passed the reserved word JOB. When this code is executed it will have visibility to the job number via the reserved word JOB.

p_status

Plain text that you want associated with

JOB: p_job.


Example

The following example shows how to use the UPDATE_JOB_STATUS procedure. In this example, note that:

BEGIN
    FOR i IN 1 .. 100 LOOP
        INSERT INTO emp(a,b) VALUES (:APP_JOB,i);
        IF MOD(i,10) = 0 THEN
            APEX_PLSQL_JOB.UPDATE_JOB_STATUS(
                P_JOB => :APP_JOB,
                P_STATUS => i || ' rows inserted');
        END IF;
        APEX_UTIL.PAUSE(2);
    END LOOP;
END;