Oracle Apex Tabular Form: Delete unsaved rows without submitting

A common shortfall in Tabular Form functionality in APEX (amongst many) is that when you add a couple of rows and you wish to delete one without saving the form, you will end up losing the whole lot of rows entered.

This piece of code will help you avoid the problem. Put this in page header and in the DELETE button's attribute, set type as URL and javascript:delete_rows(); as target.

The way it works, if the checked row wasn't saved and it will be removed without page submission, otherwise the page will be submitted to remove it via normal mechanism.

<script language="JavaScript" type="text/javascript">
    function delete_rows()
    {
        var need_submit = 0;
        $("[name='f01']").each(function(){

        if($(this).attr("checked"))
        {
            if(this.value == 0) // new row, not saved. Checkbox value is 0
            {
                $(this).closest("tr").remove();
            }
            else    // row was saved before, need to be removed via page submission.
                need_submit = need_submit + 1;
           
        }

        });
       
        if(need_submit > 0)    // require submission?
            apex.submit('MULTI_ROW_DELETE');
           
        addTotal();   

    }

</script>

Oracle Apex - Dynamically Color Text field

It is often useful to highlight certain fields when certain (usually incorrect) values are entered as a form of on the fly validation. 

Suppose you had a fairly large form with many fields many of which only accept numbers. It would be much more user friendly if you could alert end-users to incorrect values as they enter it, rather than let them submit and have a big list of invalid entries to sift through.

1) Put the following code in page header.

<script language="JavaScript" type="text/javascript">

function setCol(pThis)

{

var vv = $v(pThis);

var cls = '#'+pThis;

if(isNaN(vv))

{

$(cls).css("background-color","red");

}

else

{

$(cls).css("background-color","white");

}

}

</script>

2) Create Dynamic Action with following configuration:

1. Type Advanced (for pre-4.2)
2. Event: change
3. Selection Type: item
4. Item(s): P1_ENAME, P1_MOB (comma seperate the list of items)
5. True Action: 
1. Action: Execute Javascript Code
2. Code: setCol(this.triggeringElement.id);
6. Affected Items:
1. Pick the items in #4 above.

What this does is basically highlight textfield when non-numeric characters are entered (isNAN). 

Here is how it should look like if implemented properly. You can take this and do more fancy stuff like validating against regex. 

http://apex.oracle.com/pls/apex/f?p=21796:1

Oracle - Move schema from one tablespace to another

Starting from 11G, Oracle offers a much simpler way to migrate schema for tablespaces with Data Pump utility. Previously you would have to export the schema and then drop the user re-import the schema and then rebuild all the indexes.

With Data Pump the process of switching tablespace is much simpler.

STEP 1: Export the schema using datapump

expdp system/system_password SCHEMAS=MY_SCHEMA DIRECTORY=DATA_PUMP_DIR DUMPFILE=MY_SCHEMA.dmp LOGFILE=expdp.log

Review the log to ensure the export is done properly.

STEP 2: Drop the user from database

 DROP USER MY_SCHEMA CASCADE;

STEP 3: Import the schema with REMAP_TABLESPACE

impdp system/my_schema SCHEMAS=MY_SCHEMA REMAP_TABLESPACE=SYSTEM:MY_SCHEMA_TBSPACE DIRECTORY=DATA_PUMP_DIR DUMPFILE=MY_SCHEMA.dmp LOGFILE=impdp.log

STEP 4 : Verify Tablespace Change & Validity of Objects

Check for default tablespace by running:

select username, default_tablespace from dba_users;

Also check if all objects are valid, if not compile them

SQL> select owner, status from dba_objects where upper(owner)='MY_SCHEMA';

Check the indexes:

select index_name, status from all_indexes where status ='UNUSABLE';

For more information, check out the white paper on Data Pump:

Quick Start Guide:
http://www.oracle.com/technetwork/issue-archive/2009/09-jul/datapump11g2009-quickstart-128718.pdf

Documentation:
http://docs.oracle.com/cd/B12037_01/server.101/b10825/dp_import.htm

Creating database backups using exp & and crontab

The following is a neat little script that will allow you to create logical backups (and remove old ones) of your schema in the same file system of the database.


ORACLE_BASE=/u01/app/oracle
export ORACLE_BASE
ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe
export ORACLE_HOME
ORACLE_SID=XE
export ORACLE_SID
PATH=$ORACLE_HOME/bin:$PATH
export PATH

BKUP_DEST=/home/rode/cbackups
find $BKUP_DEST -name 'backup*.dmp' -mtime +10 -exec rm {} \;



cd /home/rode/cbackups && /u01/app/oracle/product/11.2.0/xe/bin/exp schema/password FILE=backup_`date +'%Y%m%d-%H%M'`.dmp

You will need to change the bits highlighted in orange with paths of your system. The script starts by exporting necessary paths, then removes any old backups greater than 10 days before using the exp utility to create the backup.

To set it up, follow these instructions: 

1. Create a directory where the backups will be stored. In my case it is: /home/ai/cbackups
2. Open vi and save the scripts (after replacing bits in orange with your own setup) in your home directory as say: /home/ai/backup_script.sh
3. Next, run crontab -e to set up a new cron job.
4. Add an entry like:
   10 0 * * * /home/ai/backup_script.sh

Above the the script will run every 10 minutes past midnight. Check out this link on how to schedule crontab: http://www.adminschoice.com/crontab-quick-reference


You may opt (and better idea) to use data pump instead as it supercedes the export/import utilities and if exporting involves lots of data. Check this document on how to use data pump:
http://www.oracle.com/technetwork/issue-archive/2009/09-jul/datapump11g2009-quickstart-128718.pdf

Resolving ORA-01940 error

This post shows how to get around ORA-01940 error. You typically get this error when the schema you are trying to drop is connected to something (presumably another application).

The following script will allow you to kill the sessions and drop the schema.

set serveroutput on
DECLARE
  cursor c1 is select SID, SERIAL# from v$session where username = '<schema_name';
BEGIN
FOR rec IN c1 loop
EXECUTE IMMEDIATE 'alter system kill session '''||rec.SID||','||rec.SERIAL#||'''';
end loop;
DROP USER <SCHEMA_NAME> CASCADE;
END;

Oracle Apex: Adding Up Tabular Form Column Values

Often with tabular form we get the requirement to tally up the total of one of the columns as user add/edit/delete rows of data.

In this post I'll show an easy & efficient way to achieve this using Javascript.

Step 1

Get your Javascript function to add-up the total ready. I have created a simple function which you can customise for your application. You will need to know the ID of the tabular form element you are trying to add.

All editable APEX tabular forms that are ID'ed like f0x_000x. You can find them out by using Firebug (chrome, firefox) or IE Developer Tool by hitting F12 as below. 

In my case I need add up the total in Salary column as I add rows or edit entries and add it to the Total Salary text field above the tabular form.

So here is the script. Find out the ID of your field and update the italics part. 

<script language="JavaScript" type="text/javascript">

 function addTotal()
 {
  var items = document.getElementsByName("f07"); // Tabular form column to add up
  
  $total = 0;
  $itemValue = 0;
  for (var i = 0; i < items.length; i++)
  {  
   // if non-numeric character was entered, it will be considered as 0, 
   // isNaN returns true if anything but number was entered
   if(isNaN(items[i].value) || items[i].value == null || items[i].value == "")
    $itemValue = 0;
   else
    $itemValue = parseFloat(items[i].value); // convert to number
   
   $total =$total+ $itemValue; // add up
  } 
  
  // $x sets the text field to be updated to the column total just calculated
  $x('P5_TOTAL_SALARY').value = $total;
 }

</script>

STEP 2. Test out the javascript.

Its a good idea to make sure your code works before putting it page attribute. So open up Firebug, go to the console tab and copy & paste the body of the function (everything in between the curly braces) and hit enter. If your Total Salary textfield gets updated as below then the function is working fine. 

STEP 3. 

Go to page attribute and in HTML Header & Body Attribute enter the code above.

STEP 4.
Next in page attribute, go to Javascript tab and  and add the newly created function addTotal() to where it says Execute when Page Loads. This will ensure that columns are totaled when page is loaded.

STEP 5. 

I will wrap that tabular form with a < DIV> tag and call this addTotal() function with onkeyup event. This will update the column total on every subsequent entries. 

With these steps, you should be able to add up the total of a tabular form column.

Here is how the it should behave if you implement the above steps correctly. 

http://apex.oracle.com/pls/apex/f?p=63895:5 

Script to Get Oracle Database Size

Save the following code as SQL file and run it via SQL developer or SQLPlus as SYSDBA to get the database size (dont forget the / in the end).

SET SERVEROUTPUT ON

Declare

  ddf Number:= 0;

  dtf Number:= 0;

  log_bytes Number:= 0;

  total Number:= 0;

BEGIN

  select sum(bytes)/power(1024,3) into ddf from dba_data_files;

  select sum(bytes)/power(1024,3) into dtf from dba_temp_files;

  select sum(bytes)/power(1024,3) into log_bytes from v$log;

  total:= round(ddf+dtf+log_bytes, 3);

  dbms_output.put_line('TOTAL DB Size is: '||total||'GB ');

END;
/