Category: Oracle

BIG checkboxes

Getting older, it’s getting harder to see and click those tiny checkboxes…

checkboxestoosmall

csscheckboxes

input[type=checkbox] {
/* Double-sized Checkboxes */
-ms-transform: scale(2); /* IE */
-moz-transform: scale(2); /* FF */
-webkit-transform: scale(2); /* Safari and Chrome */
-o-transform: scale(2); /* Opera */
}

checkboxesbig

CAN YOU SEE THEM NOW? Ah, good. That’s all right then.

Brought to you by dept-of-coding-by-copy-and-paste.

Google Map Apex Plugins

I’ve published two three Apex Region Plugins on apex.world that allow you to incorporate a simple Google Map region into your application. They’re easy to use, and you don’t need to apply for a Google API key or anything like that (although you can plug your key in if you have one, which enables a few additional features).

1. Simple Map

plugin-simplemap-preview

This allows you to add a small map to a page to allow the user to select any arbitrary point. If you synchronize it with an item on your page, it will put the Latitude, Longitude into that item. If the item has a value on page load, or is changed, the pin on the map is automatically updated.

Source

2. Report Map

plugin-reportmap-preview.png

This allows you to add a map to a page, and based on a SQL query you supply, it will render a number of pins on the map. Each pin has an ID, a name (used when the user hovers over a pin), and an info text (which can be almost any HTML, rendered in a popup window when the user clicks a pin).

If the user clicks a pin, the ID can be set in a page item.

Source

3. GeoHeatMap

Visualise a large set of data points on the map using the Google Maps “Heatmap” visualisation. All you need to do is supply a SQL Query that returns the data points to show, and the visualisation library does the rest.

plugin-heatmap-preview

Your SQL Query must be in the following format:

select lat, lng, weight from mydata;

You can set the Map Style (e.g. to the light blue/greyscale style you see above) easily on this plugin; just copy-and-paste the style codes from a site like snazzymaps.com.

Source

I’m very open to feedback, issues and contributions on all of these. Best way is to raise an issue on the associated github page. Have fun!

Refer to my Plugins page for future updates.

Apex API for Tabular Forms

grid-edit
Ever since I started exploring the idea of using a TAPI approach with Apex, something I was never quite satisfied with was Tabular Forms.

They can be a bit finicky to work with, and if you’re not careful you can break them to the point where it’s easier to recreate them from scratch rather than try to fix them (although if you understand the underlying mechanics you can fix them [there was an article about this I read recently but I can’t find it now]).

I wanted to use the stock-standard Apex tabular form, rather than something like Martin D’Souza’s approach – although I have used that a number of times with good results.

In the last week or so while making numerous improvements to my TAPI generator, and creating the new Apex API generator, I tackled again the issue of tabular forms. I had a form that was still using the built-in Apex ApplyMRU and ApplyMRD processes (which, of course, bypass my TAPI). I found that if I deleted both of these processes, and replaced them with a single process that loops over the APEX_APPLICATION.g_f0x arrays, I lose a number of Tabular Form features such as detecting which records were changed.

Instead, what ended up working (while retaining all the benefits of a standard Apex tabular form) was to create a row-level process instead. Here’s some example code that I put in this Apex process that interfaces with my Apex API:

VENUES$APEX.apply_mr (rv =>
  VENUES$TAPI.rv
    (venue_id   => :VENUE_ID
    ,name       => :NAME
    ,version_id => :VERSION_ID
    ));

The process has Execution Scope set to For Created and Modified Rows. It first calls my TAPI.rv function to convert the individual columns from the row into an rvtype record, which it then passes to the Apex API apply_mr procedure. The downside to this approach is that each record is processed separately – no bulk updates; however, tabular forms are rarely used to insert or update significant volumes of data anyway so I doubt this would be of practical concern. The advantage of using the rv function is that it means I don’t need to repeat all the column parameters for all my API procedures, making maintenance easier.

The other change that I had to make was ensure that any Hidden columns referred to in my Apply process must be set to Hidden Column (saves state) – in this case, the VERSION_ID column.

Here’s the generated Apex API apply_mr procedure:

PROCEDURE apply_mr (rv IN VENUES$TAPI.rvtype) IS
  r VENUES$TAPI.rowtype;
BEGIN
  log_start('apply_mr');

  UTIL.check_authorization('Operator');

  IF APEX_APPLICATION.g_request = 'MULTI_ROW_DELETE' THEN

    IF v('APEX$ROW_SELECTOR') = 'X' THEN
      VENUES$TAPI.del (rv => rv);
    END IF;

  ELSE

    CASE v('APEX$ROW_STATUS')
    WHEN 'C' THEN

      r := VENUES$TAPI.ins (rv => rv);

    WHEN 'U' THEN

      r := VENUES$TAPI.upd (rv => rv);

    ELSE
      NULL;
    END CASE;

  END IF;

  log_end;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END apply_mr;

The code uses APEX$ROW_STATUS to determine whether to insert or update each record. If the Delete button was pressed, it checks APEX$ROW_SELECTOR to check that the record had been selected for delete – although it could skip that check since Apex seems to call the procedure for only the selected records anyway. The debug logs show Apex skipping the records that weren’t selected.

Now, before we run off gleefully inserting and updating records we should really think about validating them and reporting any errors to the user in a nice way. The TAPI ins and upd functions do run the validation routine, but they don’t set up UTIL with the mappings so that the Apex errors are registered as we need them to. So, we add a per-record validation in the Apex page that runs this:

VENUES$APEX.val_row (rv =>
  VENUES$TAPI.rv
    (venue_id   => :VENUE_ID
    ,name       => :NAME
    ,version_id => :VERSION_ID
    )
  ,region_static_id => 'venues');
RETURN null;

As for the single-record page, this validation step is of type PL/SQL Function (returning Error Text). Its Execution Scope is the same as for the apply_mr process – For Created and Modified Rows.

Note that we need to set a static ID on the tabular form region (the generator assumes it is the table name in lowercase – e.g. venues – but this can be changed if desired).

The val_row procedure is as follows:

PROCEDURE val_row
  (rv               IN VENUES$TAPI.rvtype
  ,region_static_id IN VARCHAR2
  ) IS
  dummy            VARCHAR2(32767);
  column_alias_map UTIL.str_map;
BEGIN
  log_start('val_row');

  UTIL.pre_val_row
    (label_map        => VENUES$TAPI.label_map
    ,region_static_id => region_static_id
    ,column_alias_map => column_alias_map);

  dummy := VENUES$TAPI.val (rv => rv);

  UTIL.post_val;

  log_end;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END val_row;

The pre_val_row procedure tells all the validation handlers how to register any error message with APEX_ERROR. In this case, column_alias_map is empty, which causes them to assume that each column name in the tabular form is named the same as the column name on the database. If this default mapping is not correct for a particular column, we can declare the mapping, e.g. column_alias_map('DB_COLUMN_NAME') := 'TABULAR_FORM_COLUMN_NAME';. This way, when the errors are registered with APEX_ERROR they will be shown correctly on the Apex page.

Things got a little complicated when I tried using this approach for a table that didn’t have any surrogate key, where my TAPI uses ROWID instead to uniquely identify a row for update. In this case, I had to change the generated query to include the ROWID, e.g.:

SELECT t.event_type
      ,t.name
      ,t.calendar_css
      ,t.start_date
      ,t.end_date
      ,t.last_updated_dt
      ,t.version_id
      ,t.ROWID AS p_rowid
FROM   event_types t

I found if I didn’t give a different alias for ROWID, the tabular form would not be rendered at runtime as it conflicted with Apex trying to get its own version of ROWID from the query. Note that the P_ROWID must also be set to Hidden Column (saves state). I found it strange that Apex would worry about it because when I removed* the ApplyMRU and ApplyMRD processes, it stopped emitting the ROWID in the frowid_000n hidden items. Anyway, giving it the alias meant that it all worked fine in the end.

* CORRECTION (7/11/2016): Don’t remove the ApplyMRU process, instead mark it with a Condition of “Never” – otherwise Apex will be unable to map errors to the right rows in the tabular form.

The Add Rows button works; also, the Save button correctly calls my TAPI only for inserted and updated records, and shows error messages correctly. I can use Apex’s builtin Tabular Form feature, integrated neatly with my TAPI instead of manipulating the table directly. Mission accomplished.

Source code/download: https://bitbucket.org/jk64/jk64-sample-apex-tapi

Dumb triggers? Let’s make ’em a bit smarter

Some time back, Connor rightly pointed out that triggers that modify data can get in the way when you need to do out-of-the-ordinary data maintenance, e.g. when you need to fix up a row here or re-insert a row over there. You can’t just disable the trigger or else make your users suffer down-time.

Now, the only purpose for which I use triggers is to do common things like setting audit columns and incrementing a VERSION_ID column, and in certain special cases for carefully implementing cross-row constraints; also, I use them to populate a journal table with all changes to the table. Mind you, in recent times features have been added and improved in the Oracle database (such as Flashback Query and Flashback Data Archive) to the point where I’m almost ready to stop doing this. However, there are still some minor use-cases where having a separate “journal” table can be useful. Any argument about that assertion is ruled “out of scope” for this article! :)

So, assuming we’re sticking with triggers that might change data, a solution to this problem is already built-in to the journal triggers and Table APIs (TAPI) that my PL/SQL code generator creates. This allows me to disable the trigger on any table, just for my current session without affecting any other concurrent activity – and no DDL required.

UPDATED 16/2/2016: now uses a context variable (thanks Connor for the idea)

In the trigger I have this code:

create or replace TRIGGER EMPS$TRG 
  FOR INSERT OR UPDATE OR DELETE ON EMPS 
  COMPOUND TRIGGER 
 
  BEFORE EACH ROW IS 
  BEGIN 
    IF SYS_CONTEXT('SAMPLE_CTX','EMPS$TRG') IS NULL THEN 
      ...etc... 
    END IF; 
  END BEFORE EACH ROW; 
 
  AFTER EACH ROW IS 
  BEGIN 
    IF SYS_CONTEXT('SAMPLE_CTX','EMPS$TRG') IS NULL THEN 
      ...etc... 
    END IF; 
  END AFTER EACH ROW; 
 
END EMPS$TRG;

The trigger takes advantage of some extra code that is generated in the Table API:

create or replace PACKAGE EMPS$TAPI AS 
/***********************************************
 Table API for emps 
 10-FEB-2016 - Generated by SAMPLE
***********************************************/ 

... 
 
-- Use these procedures to disable and re-enable the
-- journal trigger just for this session (to disable for
-- all sessions, just disable the database trigger 
-- instead). 
PROCEDURE disable_journal_trigger; 
PROCEDURE enable_journal_trigger; 
 
END EMPS$TAPI; 

The package body code is quite simple:

create or replace PACKAGE BODY EMPS$TAPI AS 
/***********************************************
 Table API for emps 
 10-FEB-2016 - Generated by SAMPLE
***********************************************/ 
 
...

-- may be used to disable and re-enable the journal trigger for this session 
PROCEDURE disable_journal_trigger IS 
BEGIN 
  log_start('disable_journal_trigger'); 
 
  SECURITY.disable_journal_trigger('EMPS$TRG');
 
  log_end;
EXCEPTION 
  WHEN OTHERS THEN 
    UTIL.log_sqlerrm; 
    RAISE; 
END disable_journal_trigger; 
 
PROCEDURE enable_journal_trigger IS 
BEGIN 
  log_start('enable_journal_trigger'); 
 
  SECURITY.enable_journal_trigger('EMPS$TRG');
 
  log_end; 
EXCEPTION 
  WHEN OTHERS THEN 
    UTIL.log_sqlerrm; 
    RAISE; 
END enable_journal_trigger; 
 
END EMPS$TAPI;

A context variable is set with the name of the trigger to disable it – the default state for a new session (i.e. the context variable not set) means the trigger is enabled.

create or replace PACKAGE BODY SECURITY AS

...

PROCEDURE disable_journal_trigger
  (trigger_name IN VARCHAR2
  ,client_id    IN VARCHAR2 := NULL) IS
BEGIN
  -- set the context to any non-null value
  DBMS_SESSION.set_context 
    (namespace => 'SAMPLE_CTX'
    ,attribute => trigger_name
    ,value     => 'DISABLED'
    ,client_id => NVL(client_id, SYS_CONTEXT('USERENV','CLIENT_IDENTIFIER')));
END disable_journal_trigger;

PROCEDURE enable_journal_trigger
  (trigger_name IN VARCHAR2
  ,client_id    IN VARCHAR2 := NULL) IS
BEGIN
  -- clear the context
  DBMS_SESSION.clear_context 
    (namespace => 'SAMPLE_CTX'
    ,attribute => trigger_name
    ,client_id => NVL(client_id, SYS_CONTEXT('USERENV','CLIENT_IDENTIFIER')));
END enable_journal_trigger;

END SECURITY;

So now, to run some data maintenance, I can simply call the TAPI to disable, then re-enable, the trigger:

BEGIN EMPS$TAPI.disable_journal_trigger; END;
/

... do the data maintenance...

BEGIN EMPS$TAPI.enable_journal_trigger; END;
/

Unless the data maintenance is doing something very unusual, this script should be safe to run while the system is still up and running for users.

Also, it would be a trivial exercise to write a routine which disables or enables all the journal triggers at once.

The point of this, of course, is that you should be able to do all this sort of thing without writing a lot of code for each table in your schema – solve it for one table, and then generate the code for all your tables.

Source code/download: https://bitbucket.org/jk64/jk64-sample-apex-tapi

Apex API – call a package for all your DML

If you create an Apex form based on a table, Apex automatically creates processes of type Automatic Row Fetch and Automatic Row Processing (DML) as well as one item for each column in the table, each bound to the database column via its Source Type. This design is excellent as it’s fully declarative and is very quick and easy to build a data entry page for all your tables.

The downside to this approach is that if you want to use a Table API (TAPI) to encapsulate all DML activity on your tables, you need to write a whole lot of code to replace the processes that Apex created for you. In order to mitigate this as much as possible, I’ve augmented my code generator with an “Apex API” generator. This generates a second package for each table which can be called from Apex, which in turn calls the TAPI to run the actual DML. In addition, the validations that are performed by the TAPI are translated back into Apex Errors so that they are rendered in much the same way as built-in Apex validations.

Probably the best way to explain this is to show an example. Here’s my EMPS table (same as from my last article):

CREATE TABLE emps
  (emp_id       NUMBER NOT NULL
  ,name         VARCHAR2(100 CHAR) NOT NULL
  ,emp_type     VARCHAR2(20 CHAR) DEFAULT 'SALARIED' NOT NULL
  ,start_date   DATE NOT NULL
  ,end_date     DATE
  ,dummy_ts     TIMESTAMP(6)
  ,dummy_tsz    TIMESTAMP(6) WITH TIME ZONE
  ,life_history CLOB
  ,CONSTRAINT emps_pk PRIMARY KEY ( emp_id )
  ,CONSTRAINT emps_name_uk UNIQUE ( name )
  ,CONSTRAINT emp_type_ck
     CHECK ( emp_type IN ('SALARIED','CONTRACTOR')
  );
CREATE SEQUENCE emp_id_seq;

By the way, my table creation script calls DEPLOY.create_table to do this, which automatically adds my standard audit columns to the table – CREATED_BY, CREATED_DT, LAST_UPDATED_BY, LAST_UPDATED_DT, and VERSION_ID. My script also calls GENERATE.journal for the table which creates a journal table (EMPS$JN) and a trigger (EMPS$TRG) to log all DML activity against the table.

I then call GENERATE.tapi which creates the Table API (EMPS$TAPI) which has routines for validating, inserting, updating and deleting rows (or arrays of rows using bulk binds) of the EMPS table.

Finally, I call GENERATE.apexapi which creates the Apex API (EMPS$APEX) which looks like this:

Package Spec: EMPS$APEX

create or replace PACKAGE EMPS$APEX AS
/**************************************************
 Apex API for emps
 10-FEB-2016 - Generated by SAMPLE
**************************************************/

-- page load process
PROCEDURE load;

-- single-record page validation
PROCEDURE val;

-- page submit process
PROCEDURE process;

END EMPS$APEX;

Notice that these routines require no parameters; the API gets all the data it needs directly from Apex.

Package Body: EMPS$APEX

create or replace PACKAGE BODY EMPS$APEX AS
/*******************************************************************************
Table API for emps
10-FEB-2016 - Generated by SAMPLE
*******************************************************************************/

PROCEDURE apex_set (r IN EMPS$TAPI.rowtype) IS
  p VARCHAR2(10) := 'P' || UTIL.apex_page_id || '_';
BEGIN
  log_start('apex_set');

  sv(p||'EMP_ID',          r.emp_id);
  sv(p||'NAME',            r.name);
  sv(p||'EMP_TYPE',        r.emp_type);
  sd(p||'START_DATE',      r.start_date);
  sd(p||'END_DATE',        r.end_date);
  st(p||'BLA_TSZ',         r.bla_tsz);
  st(p||'DUMMY_TS',        r.dummy_ts);
  sv(p||'CREATED_BY',      r.created_by);
  sd(p||'CREATED_DT',      r.created_dt);
  sv(p||'LAST_UPDATED_BY', r.last_updated_by);
  sd(p||'LAST_UPDATED_DT', r.last_updated_dt);
  sv(p||'VERSION_ID',      r.version_id);

  log_end;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END apex_set;

FUNCTION apex_get RETURN EMPS$TAPI.rvtype IS
  p  VARCHAR2(10) := 'P' || UTIL.apex_page_id || '_';
  rv EMPS$TAPI.rvtype;
BEGIN
  log_start('apex_get');
  
  rv.emp_id     := nv(p||'EMP_ID');
  rv.name       := v(p||'NAME');
  rv.emp_type   := v(p||'EMP_TYPE');
  rv.start_date := v(p||'START_DATE');
  rv.end_date   := v(p||'END_DATE');
  rv.bla_tsz    := v(p||'BLA_TSZ');
  rv.dummy_ts   := v(p||'DUMMY_TS');
  rv.version_id := nv(p||'VERSION_ID');
    
  log_end;
  RETURN rv;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END apex_get;

FUNCTION apex_get_pk RETURN EMPS$TAPI.rvtype IS
  p  VARCHAR2(10) := 'P' || UTIL.apex_page_id || '_';
  
  rv EMPS$TAPI.rvtype;
BEGIN
  log_start('apex_get_pk');

  IF APEX_APPLICATION.g_request = 'COPY' THEN

    rv.emp_id := v(p||'COPY_EMP_ID');

  ELSE

    rv.emp_id     := nv(p||'EMP_ID');
    rv.version_id := nv(p||'VERSION_ID');
    
  END IF;

  log_end;
  RETURN rv;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END apex_get_pk;

/*******************************************************************************
                               PUBLIC INTERFACE
*******************************************************************************/

PROCEDURE load IS
  p  VARCHAR2(10) := 'P' || UTIL.apex_page_id || '_';
  rv EMPS$TAPI.rvtype;
  r  EMPS$TAPI.rowtype;
BEGIN
  log_start('load');

  UTIL.check_authorization('Reporting');

  rv := apex_get_pk;
  r := EMPS$TAPI.get (emp_id => rv.emp_id);

  IF APEX_APPLICATION.g_request = 'COPY' THEN

    r := EMPS$TAPI.copy(r);

  END IF;

  apex_set (r => r);

  log_end;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END load;

PROCEDURE val IS
  p             VARCHAR2(10) := 'P' || UTIL.apex_page_id || '_';
  rv            EMPS$TAPI.rvtype;
  dummy         VARCHAR2(32767);
  item_name_map UTIL.str_map;
BEGIN
  log_start('val');

  IF APEX_APPLICATION.g_request = 'CREATE'
  OR APEX_APPLICATION.g_request LIKE 'SAVE%' THEN

    rv := apex_get;

    UTIL.pre_val
      (label_map     => EMPS$TAPI.label_map
      ,item_name_map => item_name_map);

    dummy := EMPS$TAPI.val (rv => rv);
    
    UTIL.post_val;

  END IF;

  log_end;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END val;

PROCEDURE process IS
  p  VARCHAR2(10) := 'P' || UTIL.apex_page_id || '_';
  rv EMPS$TAPI.rvtype;
  r  EMPS$TAPI.rowtype;
BEGIN
  log_start('process');
  
  UTIL.check_authorization('Operator');

  CASE
  WHEN APEX_APPLICATION.g_request = 'CREATE' THEN

    rv := apex_get;
    
    r := EMPS$TAPI.ins (rv => rv);

    apex_set (r => r);

    UTIL.success('Emp created.');

  WHEN APEX_APPLICATION.g_request LIKE 'SAVE%' THEN

    rv := apex_get;

    r := EMPS$TAPI.upd (rv => rv);

    apex_set (r => r);
    UTIL.success('Emp updated.'
      || CASE WHEN APEX_APPLICATION.g_request = 'SAVE_COPY'
         THEN ' Ready to create new emp.'
         END);

  WHEN APEX_APPLICATION.g_request = 'DELETE' THEN

    rv := apex_get_pk;

    EMPS$TAPI.del (rv => rv);

    UTIL.clear_page_cache;

    UTIL.success('Emp deleted.');

  END CASE;

  log_end;
EXCEPTION
  WHEN UTIL.application_error THEN
    log_end('application_error');
    RAISE;
  WHEN OTHERS THEN
    UTIL.log_sqlerrm;
    RAISE;
END process;

END EMPS$APEX;

Now, given the above package, we can create an Apex page that allows users to view, create, update, copy and delete a record from the EMPS table, using all the features provided by our TAPI.

  1. Create Page, select Form, select Form on a Table or view, select the table EMPS.
  2. Accept the defaults, or change them to taste, and click Next, Next.
  3. On the Primary Key wizard step, change type to Select Primary Key Column(s) and it should pick up the EMP_ID column automatically. Click Next.*
  4. For Source Type, leave the default (Existing trigger).** Click Next, Next, Next.
  5. For Branching, enter page numbers as required. Click Next, then Create.

* the Apex API and Table API generator also handles tables with no surrogate key by using ROWID instead; in this case, you would leave the default option selected (Managed by Database (ROWID)) here.
** note however that our TAPI will handle the sequence generation, not a trigger.

The page should look something like this:

Notice that it has created a Fetch Row from EMPS process for when the page is loaded, as well as the Process Row of EMPS and reset page processes for when the page is submitted. It has also created a few validations.

Notice also that all the items are named consistently with the column names; this is important as my Apex API package generator relies on this one-to-one mapping. You can, of course, add additional non-database items to the page – they won’t be affected by the generator unless the table is altered with columns that match.

Now, this page will work fine, except that it bypasses our TAPI. To change the page so that it uses our TAPI instead, edit the page as follows:

  1. Delete all the Fetch Row from EMPS, Process Row of EMPS and reset page processes.
  2. Delete all the validations.
  3. For all the page items, set Source Type to Null. In Apex 5 this is easy – just Ctrl+Click each item, then make the change to all of them in one step!
  4. Make the audit column items (CREATED_BY, CREATED_DT, LAST_UPDATED_BY, LAST_UPDATED_DT) Display Only.
  5. Make the VERSION_ID item Hidden.
  6. Under Pre-Rendering, add an After Header process that calls EMPS$APEX.load;.
  7. In the Page Processing tab, under Validating, add a validation with Type = PL/SQL Function (returning Error Text).
  8. Set the PL/SQL Function Body Returning Error Text to EMPS$APEX.val; RETURN null;.
  9. Set Error Message to “bla” (this is a mandatory field but is never used – I think this is a small bug in Apex 5).
  10. Under Processing, add a process that calls EMPS$APEX.process;.
  11. Set Error Message to #SQLERRM_TEXT#.

Run the page – you should find that it works just as well as before, with all the TAPI goodness working behind the scenes. Even the validations work, and they will point at the right items on the page.

But that’s not all! You can easily add a useful “Copy” function that your users will thank you for because (depending on the use case) it can reduce the amount of typing they have to do.

  1. Add a button to the region, named SAVE_COPY (this name is important) with the label Copy. Tip: if you want an icon set the Icon CSS Classes to fa-copy.
  2. Add a hidden item named after the PK item prefixed with “COPY_”, e.g. P14_COPY_EMP_ID.
  3. Under After Processing, add a Branch that goes to this same page (e.g. 14, in this example).
  4. On the branch, set Request (under Advanced) to COPY and assign &P14_EMP_ID. to the item P14_COPY_EMP_ID.
  5. Set When Button Pressed to SAVE_COPY.
  6. Change the order of the branches so that the Copy branch is evaluated before the other branches (see below)

Now, when they click Copy, the page will first save any changes they had made to the record, then go back to the same page with a copy of all the details from the original record. The user can then edit the new record and Create it if they so desire, or Cancel.

An advantage of this design is that, if you want to add a validation that applies whether someone is updating the table from Apex or from some other UI or interface, you can add it in one place – the TAPI (specifically, you would add it to the TAPI template). If you add a column, just add an item to the Apex page and regenerate the TAPI and Apex API. It’s a nice DRY-compliant solution.

Addendum: you may be wondering why we need a P14_COPY_EMP_ID item, instead of simply reusing the P14_EMP_ID item that’s already there. The reason for this is that after saving a copied record, in some cases we may want to copy some or all the child records from the original record to the copy, or do some other operation that needs both the old and the new ID.

Source code/download: https://bitbucket.org/jk64/jk64-sample-apex-tapi