Load spreadsheet data into APEX

Face it: your users are in love with Microsoft Excel, and you can’t do anything about it.

You can show them the excellent Interactive Report and Interactive Grid features of APEX, and train some of your users to use some of their capabilities, but at the end of the day, your users will still download the data into their spreadsheet software to do their own stuff with it.

Once they’ve finished with the data, odds are they’ll come back to you and ask “how do I upload this data back into APEX?” and expect that the answer is merely a flip of a switch to enable a built-in APEX feature. Of course, you know and I know that this is not necessarily a simple thing; it is certainly not just an option to be enabled. Depending on what exactly they mean by “upload this data” it may be reasonably easy to build or it could get quite complex.

File Formats

Typically the data will be provided in some kind of text format (CSV, tab delimited, fixed width) or binary file (XLS or XLSX). If they have copied the data from a table in Excel, it will be in tab-delimited format in the clipboard. Perhaps in some odd instances the user will have received the data from some system in fixed width, XML or JSON format – but this is rare as this is typically part of the build of a system integration solution and users expect these to be “harder”.

Actual Requirements

When your user wants you to provide a facility for uploading data, there are some basic questions you’ll need to ask. Knowing these will help you choose the right approach and solution.

  1. Where are the files – i.e. are they stored on the database server, or is the user going to upload them via an online APEX application
  2. How much automation is required, how often – i.e. is this a ad-hoc, rare situation; something they need to do a few times per month; or something that is frequent and needs to be painless and automatic?
  3. What are the files named – i.e. if they are stored on the database server, do we know what the files will be called?
  4. How consistent is the data structure?

Data Structure

That last one is important. Will the columns in the file remain the same, or might they change all the time? If the structure is not amenable to automated data matching, can the file structure be changed to accommodate our program? Is the structure even in tabular form (e.g. is it a simple “header line, data line, data line” structure or are there bits and pieces dotted around the spreadsheet)? If it’s an Excel file, is all the data in one sheet, or is it spread across multiple sheets? Should all the sheets be processed, or should some of them be ignored? Can the columns vary depending on requirement – might there be some columns in one file that don’t exist in other files, and vice versa?

Finally, is all the data to be loaded actually encoded in text form? This is an issue where a spreadsheet is provided where the user has, trying to be helpful, highlighted rows with different colours to indicate different statuses or other categorising information. I’ve received spreadsheets where some data rows were not “real” data rows, but merely explanatory text or notes entered by the users – since they coloured the background on those rows in grey, they expected my program to automatically filter those rows out.

Solution Components

Any solution for processing uploaded files must incorporate each of the following components:

  • Load – read the raw file data
  • Parse – extract the text data from the file
  • Map – identify how the text data relates to your schema
  • Validate – check that the data satisfies all schema and business rule constraints
  • Process – make the relevant changes in the database based on the data

Each of these components have multiple solution options, some are listed here:

  • Load – External tables / SQL*Loader; APEX file select
  • Parse – External tables / SQL*Loader; APEX; 3rd-party code
  • Map – Fixed (we already know which columns appear where) (e.g. SQL*Loader Express Mode); Manual (allow the user to choose which column maps to which target); or A.I. (use some sort of heuristic algorithm to guess which column maps to what, e.g. based on the header labels)
  • Validate – Database constraints; and/or PL/SQL API
  • Process – INSERT; MERGE; or call a PL/SQL API

The rest of this post is focussed primarily on Parsing and Mapping Text and Excel files.

Solutions for Text files

These are some solutions for parsing text files (CSV, tab-delimited, fixed-width, XML, etc.) that I’ve used or heard of. “Your Mileage May Vary” – so test and evaluate them to determine if they will suit your needs.

  • External Table / SQL*Loader / SQL*Loader Express Mode (CSV, delimited, and fixed width files)
  • XML – native SQL using XMLType
  • APEX Data Workshop (CSV, delimited, and XML files)
  • APEX Data Loader Wizard (CSV and delimited files only)
  • Alexandria PL/SQL Library CSV_UTIL_PKG – Morten Braten, 2010
  • LOB2Table PL/SQL (CSV, delimited and fixed width files) – Michael Schmid, 2015
  • Excel2Collection APEX process plugin (CSV, delimited, XLS and XLSX files) – Anton Scheffer, 2013

It could be noted here that the Interactive Grid in APEX 5.1 and later does support Paste; if the user selects some data from Excel, then selects the corresponding columns and rows in the grid, they can Paste the tab-delimited data right in. Of course, this requires that the columns be in exactly the right order.

External Table

This uses the SQL*Loader access driver and you can look up the syntax in the Oracle docs by searching for “ORACLE_LOADER”. Since Oracle 12.1 you can use the simple “FIELDS CSV” syntax to parse CSV files, e.g.:

create table emp_staging
  ( emp_no number(4)
  , name   varchar2(10)
  , ...
  )
organization external
  ( default directory ext_dir
    access parameters
      ( records delimited by newline
        FIELDS CSV
        reject rows with all null fields
      )
    location ( 'emp.dat' )
  )
reject limit unlimited

Note that the filename (location) is hard-coded in the external table definition. Since Oracle 12.2 you can modify some of the attributes of an external table such as file name directly in the SELECT statement, without requiring any ALTER TABLE – Override External Table Parameters From a Query in Oracle Database 12c Release 2 (12.2).

SQL*Loader Express Mode

Since Oracle 12.1 the sqlldr command-line utility supports “Express Mode” which by default reads a CSV file, and loads the data into a given table. Read this quick intro here. This can come in handy for scripting the load of a number of CSV files on an ad-hoc basis into tables that already have exactly the same structure as those CSV files.

> sqlldr userid=scott/tiger table=emp 

This expects to find a file named “emp.dat” which contains CSV data to be loaded into the nominated table. Internally, it creates a temporary external table to load the data. Additional parameters can be added to change the filename, delimiters, field names, and other options.

APEX Data Workshop

The APEX Data Workshop is found under SQL Workshop > Utilities > Data Workshop and allows the developer to quickly load data from a CSV, tab-delimited, XML, or copy-and-paste from Excel into an existing or new table. This can be very handy when your client sends you some spreadsheets and you need to quickly load the data as one or more tables.

A related utility is the Create Application from Spreadsheet which does the same thing, plus creates a basic application to report and maintain the data in the new table.

APEX Data Loader Wizard

If your users need to load data on an ad-hoc, on-demand basis, and you don’t know necessarily what the structure of the files will be (e.g. the headings might change, or the order of the columns might change), you can use the APEX Data Loader Wizard to build an APEX application that guides your users in loading, mapping, and validating the data for themselves. If required you can customise the generated pages to add your own processing.

To create the wizard, click Create Page, choose Data Loading, and follow the steps to define the Data Load Definition and its associated pages. The definition determines the target table, the unique column(s) for data matching, transformation rules, and lookups (e.g. to get foreign keys for reference tables). Once this is done, the following four pages will be created for you:

You can customise these pages to modify the look and feel (e.g. moving some of the more complicated options in a collapsible region), or to add your own custom processing for the data.

For example, I will often add an additional process on either the 3rd page (to be run after the “Prepare Uploaded Data” process) that will do further processing of the loaded data. The process would be set up to only run When Button Pressed = “NEXT” and would have a Condition “Item is NULL or Zero” = “P111_ERROR_COUNT”. The result is that on the Data Validation (3rd) page, after reviewing the validation summary, the user clicks “Next” and the data is loaded and processed.

Alternatively, I sometimes want the user to view additional validation or summary information on the 4th page before doing further processing. In this case, I would add the process to the Data Load Results (4th) page, When Button Pressed = “FINISH”. For this to work, you need to modify the FINISH button to Submit the page (instead of redirecting). I also would add a CANCEL button to the page so the user can choose to not run the final processing if they wish.

Updating a Data Load Definition

The Data Load Definitions (one for each target table) may be found under Shared Components > Data Load Definitions. Here, you can modify the transformations and lookup tables for the definition. However, if the table structure has changed (e.g. a new column has been added), it will not automatically pick up the change. To reflect the change in the definition, you need to follow the following steps:

  1. Edit the Data Load Definition
  2. Click Re-create Data Load Pages
  3. Delete the new generated pages

This refreshes the Data Load Definition and creates 4 new pages for the wizard. Since you already had the pages you need (possibly with some customisations you’ve made) you don’t need the new pages so you can just delete them.

CSV_UTIL_PKG

The Alexandria PL/SQL Library includes CSV_UTIL_PKG which I’ve used in a number of projects. It’s simple to use and effective – it requires no APEX session, nothing but PL/SQL, and can be called from SQL for any CLOB data. It’s handy when you know ahead of time what the columns will be. You could read and interpret the headings in the first line from the file if you want to write some code to automatically determine which column is which – but personally in this case I’d lean towards using the APEX Data Loader Wizard instead and make the user do the mapping.

If you don’t already have the full Alexandria library installed, to use this package you must first create the schema types t_str_array and t_csv_tab. You will find the definition for these types in setup/types.sql. After that, simply install ora/csv_util_pkg.pks and ora/csv_util_pkg.pkb and you’re good to go.

In the example below I get a CSV file that a user has uploaded via my APEX application, convert it to a CLOB, then parse it using CSV_UTIL_PKG.clob_to_csv:

procedure parse_csv (filename in varchar2) is
    bl blob; cl clob;
begin

    select x.blob_content into bl
    from apex_application_temp_files x
    where x.name = parse_csv.filename;

    cl := blob_to_clob(bl);

    insert into csv_staging_lines
          (session_id, line_no, school_code, school_name
          ,line_type, amount, line_description)
    select sys_context('APEX$SESSION','APP_SESSION')
          ,line_number - 1
          ,c001 as school_code
          ,c002 as school_name
          ,c003 as line_type
          ,replace(replace(c004,'$',''),',','') as amount
          ,c005 as line_description
    from   table(csv_util_pkg.clob_to_csv(cl, p_skip_rows => 1))
    where  trim(line_raw) is not null;

end parse_csv;

Read more details on CSV_UTIL_PKG here.

LOB2Table

This PL/SQL package written and maintained by Michael Schmid parses CSV, delimited or Fixed-width data embedded in any LOB or VARCHAR2, including in a table with many records. The data can be read from any CLOB, BLOB, BFILE, or VARCHAR2. This makes it quite versatile, it reportedly provides excellent performance, and it includes a pipelined option. It will read up to 200 columns, with a maximum of 32K per record.

It requires execute privileges on SYS.DBMS_LOB and SYS.UTL_I18N and creates some object types and a database package. You can download the source from sourceforge. It appears to be well supported and was most recently updated in June 2018. I recommend checking it out.

select d.deptno, d.dname,
       t.row_no,
       t.column1, t.column2,
       t.column3, t.column4from dept d
cross join table( 
  lob2table.separatedcolumns(
    d.myclob, /* the data LOB */
    chr(10),  /* row separator */
    ',',      /* column separator */
    '"'       /* delimiter (optional) */
) ) t;

Excel2Collection

This is a process type APEX plugin written by Anton Scheffer (AMIS) in 2013, and has been actively maintained since then. You can download it from here or find it on apex.world.

The plugin detects and parses CSV, XLS, XML 2003 and XLSX files which makes it very versatile. It will load 50 columns from the spreadsheet into an APEX collection (max 10K rows). If you need to load larger spreadsheets you can send Anton a donation and your email address and he’ll send you a database package that can handle larger files.

Solutions for Excel files

The first thing to know about XLSX files is that they are basically a ZIP file containing a folder structure filled with a number of XML documents. Parsing an XLSX file, therefore, involves first unzipping the file, reading the relevant XML documents and parsing their contents. As usual with any Microsoft file format, the internal structure of these XML documents can be quite complex so I’d much rather leave the work to someone who has already worked out the details. Thankfully, this has largely been done.

These are some solutions for loading data from Microsoft Excel files (XLS, XLSX) that I’ve come across. Again, “YMMV” – so test and evaluate them to determine if they will suit your needs.

OOXML_UTIL_PKG

The Alexandria PL/SQL Library includes OOXML_UTIL_PKG which provides a number of utilities for parsing (and creating) XLSX, DOCX and PPTX files. It provides functions to get file attributes (including title, creator, last modified) and a list of worksheets in an XLSX. It provides functions to get the text data from any cell in any sheet, although for reasonable performance if you need more than one cell you should use the functions that returns a range of cells in one go.

Installation requires zip_util_pkg, sql_util_pkg, string_util_pkg, xml_util_pkg, xml_stylesheet_pkg, and ooxml_util_pkg, all of which are in the Alexandria library. Given this list of dependencies (and probably others I didn’t notice) I recommend installing the whole library – after all, there’s a lot of useful stuff in there so it’s worth it.

declare
  l_blob   blob;
  l_names  t_str_array := t_str_array('B3','C3','B4','C4','B5','C5');
  l_values t_str_array;
begin
  l_blob := file_util_pkg.get_blob_from_file('EXT_DIR','sample.xlsx');
  l_values := ooxml_util_pkg.get_xlsx_cell_values(l_blob, 'Sheet1', l_names);
  for i in 1..l_values.count loop
    dbms_output.put_line(l_names(i) || ' = ' || l_values(i));
  end loop;
end;

More details on OOXML_UTIL_PKG here.

Excel2Collection

As noted above, the Excel2Collection APEX plugin can detect and parse XLS, XML 2003 and XLSX files (as well as CSV files). The fact that it detects the file type automatically is a big plus for usability.

Apache POI

This solution involves installing Apache POI (“Poor Obfuscation Implementation”), a Java API for Microsoft products, into the database. The solution described by Christian Neumueller here parses XLS and XLSX files although it is admittedly not very efficient.

XLSX_PARSER

In 2018 Carsten Czarski posted a blog article “Easy XLSX Parser just with SQL and PL/SQL” listing a simple database package that parses XLSX files. This uses APEX_ZIP which comes with APEX, although using it does not require an APEX session or collections. It can load the file from a BLOB, or from APEX_APPLICATION_TEMP_FILES. It uses XMLTable to parse the XML content and return the text content of up to 50 columns for any worksheet in the file. It may be modified to support up to 1,000 columns.

To get a list of worksheets from a file:

select * from table( 
  xlsx_parser.get_worksheets( 
    p_xlsx_name => :P1_XLSX_FILE
  ));

To get the cells from a worksheet:

select * from table( 
  xlsx_parser.parse( 
    p_xlsx_name      => :P1_XLSX_FILE, 
    p_worksheet_name => :P1_WORKSHEET_NAME
  ));

I used this solution in a recent APEX application but the client was still on APEX 4.2 which did not include APEX_ZIP; so I adapted it to use ZIP_UTIL_PKG from the Alexandria PL/SQL Library. If you’re interested in this implementation you can download the source code from here.

ExcelTable

ExcelTable is a powerful API for reading XLSX, XLSM, XLSB, XLS and ODF (.ods) spreadsheets. It is based on PL/SQL + Java and reportedly performs very well. It requires a grant on DBMS_CRYPTO which allows it to read encrypted files. It includes an API for extracting cell comments as well. It can return the results as a pipelined table or as a refcursor. It knows how to interpret special cell values and error codes such as booleans, #N/A, #DIV/0!, #VALUE!, #REF! etc.

It includes API calls that allow you to map the input from a spreadsheet to insert or merge into a table, defining how to map columns in the spreadsheet to your table columns, which may improve throughput and may mean it uses less memory to process large files.

The API was written by Marc Bleron in 2016 and has been in active maintenance since then (latest update 22/10/2018 as of the writing of this article). You can read more details and download it from here: https://github.com/mbleron/ExcelTable

EDIT 17/12/2018: thanks to Nicholas Ochoa who alerted me to this one.

APEX 19.1 Statement of Direction

DISCLAIMER: all comments and code samples regarding APEX 19.1 in this article are based primarily on the Statement of Direction and are subject to Oracle’s “Safe Harbour” provision and must therefore not be relied on when making business decisions.

The SOD for the next release of APEX includes the following note, which is exciting:

“New Data Loading: The data upload functionality in SQL Workshop will be modernized with a new drag & drop user interface and support for native Excel, CSV, XML and JSON documents. The same capabilities will be added to the Create App from Spreadsheet wizard and a new, public data loading PL/SQL API will be made available.”

Whether this release will include corresponding enhancements to the APEX Data Loader Wizard remains to be seen; I hope the wizard is enhanced to accept XLSX files because this is something a lot of my users would be happy about.

APEX_DATA_PARSER

The most promising part of the APEX 19.1 SOD is the PL/SQL API bit, which will mean no plugins or 3rd-party code will be needed to parse XLSX files. It appears the package will be called APEX_DATA_PARSER, providing routines to automatically detect and parse file formats including XLSX, XML, JSON and CSV/tab-delimited files, e.g.:

select * from table(
  apex_data_parser.parse(
    p_content => blob,
    p_file_name => 'test.xlsx',
    p_xlsx_sheet_name => 'sheet1.xml'));
select * from table(
  apex_data_parser.parse(
    p_content => blob,
    p_file_name => 'test.xml'));
select * from table(
  apex_data_parser.parse(
    p_content => blob,
    p_file_name => 'test.js'));
select * from table(
  apex_data_parser.parse(
    p_content => blob,
    p_file_name => 'test.csv'));

Capability Matrix

CSV Fixed width XML XLS XLSX
External Table Yes Yes
APEX Data Workshop Yes Yes 19.1?
APEX Data Loader Wizard Yes
CSV_UTIL_PKG Yes
LOB2Table Yes Yes
Excel2Collection Yes Yes Yes
OOXML_UTIL_PKG Yes
Apache POI Yes Yes
XLSX_PARSER Yes
APEX_DATA_PARSER 19.1 19.1 19.1
ExcelTable Yes Yes

Have I missed a tool or 3rd-party code that you have found useful for parsing files to load into your APEX application? If so, please comment below.

This blog post is partially based on the following presentation delivered at the AUSOUG Connect 2018 Perth conference, November 2018.

Related


Using apex_item.checkbox2 with multiple identifiers

Normally, in a report you can add a checkbox to select records like this:

select apex_item.checkbox2(1,x.id) as sel
      ,x.mycol
      ,...
from mytable x

And process the selected records using a process like this:

for i in 1..apex_application.g_f01.count loop
  l_id := apex_application.g_f01(i);
  -- ... process ...
end loop;

Since we have set the value of the checkbox to the record ID we can just get that ID from the resulting g_f01 array. What if we need multiple columns in our processing? There are a few approaches we could use:

Option 1. Re-query the table to get the corresponding data for the record ID

This is possible as long as the record ID is a unique identifier for the results in the report. A downside is that this involves running an extra query to get the corresponding data which might add a performance problem. An advantage is that the query can bring back as much data as we need – so if we need more than, say, 6 or 7 columns, this would be a reasonable approach.

Option 2. Concatenate the extra data into the checkbox value

For example:

select apex_item.checkbox2(1, x.col1 || ':' || x.col2) as sel
      ,x.mycol
      ,...
from mytable x

This requires parsing the value in the process, e.g.:

for i in 1..apex_application.g_f01.count loop
  l_buf := apex_application.g_f01(i);
  l_col1 := substr(l_buf, 1, instr(l_buf,':')-1);
  l_col2 := substr(l_buf, instr(l_buf,':')+1);
  -- ... process ...
end loop;

Option 3. Add extra hidden items to hold the data

select apex_item.checkbox2(1,rownum)
       || apex_item.hidden(2,rownum)
       || apex_item.hidden(3,col1)
       || apex_item.hidden(4,col2)
       as sel
      ,x.mycol
      ,...
from mytable x

Note: using “rownum” like this allows selecting the data from the row in the report, even if the underlying view for the report has no unique values that might be used.

Processing involves getting the selected rownums from the checkbox, then searching the hidden item (#2) for the corresponding rownum. This is because the g_f01 array (being based on a checkbox) will only contain elements for the selected records, whereas the g_f02, g_f03, etc. arrays will contain all elements from all records that were visible on the page.

for i in 1..apex_application.g_f01.count loop
  for j in 1..apex_application.g_f02.count loop
    -- compare the ROWNUMs
    if apex_application.g_f02(j) = apex_application.g_f01(i)
    then
      l_col1 := apex_application.g_f03(j);
      l_col2 := apex_application.g_f04(j);
      -- ... process ...
    end if;
  end loop;
end loop;

This approach helped when I had a report based on a “full outer join” view, which involved multiple record IDs which were not always present on each report row, and I had multiple processes that needed to process based on different record IDs and other data, which would have been too clumsy to concatenate and parse (as per option #2 above).


Quick tip: List all interactive reports with email features enabled

I was working on an application in an APEX instance that was not configured for email (and would not be), but a number of interactive reports were allowing users to use the “Subscription” or the “Download as Email” features. If they tried these features, those emails would just go into the APEX mail queue and never go anywhere, so I needed to turn these off.

I listed all the interactive reports that need fixing with this query:

select page_id
      ,region_name
      ,show_notify
      ,download_formats
from apex_application_page_ir
where application_id = <my app id>
and (show_notify = 'Yes' or instr(download_formats,'EMAIL') > 0);

Quick tip: List all tabular forms

I needed to get a list of all the tabular forms in my application along with which table they were based on. This query did the trick:

select page_id
      ,attribute_02 as data_source
      ,page_name
      ,region_name
      ,attribute_03 as key_column
from   apex_application_page_proc
where  application_id = <my app id>
and    process_type_code = 'MULTI_ROW_UPDATE'
order by 1, 2;


Convert an APEX Application to Multi-Tenant

So you’ve built an APEX application to solve a problem for one client, or one department, or just yourself – and you think it might be useful for others as well. How do you make that application available for other users, departments, or companies to reuse, while ensuring each sees only their own data and cannot mess around with others’ data?

Architecting a Multi-Tenant Application

To make your application multi-tenant you have a few options.

Option #1. Copy the application to another workspace/schema, another Pluggable Database (in Oracle 12c+) or another database server entirely.

Option #2. Modify your data model to allow completely independant sets of data to co-exist in the same physical tables (e.g. a security_group_id column that allows the database to discriminate data for each tenant).

The desirable properties of a multi-tenant system are as follows:

a. Tenant isolation – no tenant sees data for another tenant; no tenant can affect the app’s behaviour for another tenant; protect against “noisy neighbours” (i.e. those which impact system capacity and performance).

Hadlow’s first law of multi-tenancy: A multi-tenanted application should not look like a multi-tenanted application.”

b. Administration – ability to backup/recover all data for a single tenant; ability to give a degree of control to each tenant (self service).

c. Maintainability – simplicity of deploying enhancements and bug fixes for all tenants, or for one tenant at a time (e.g. rolling upgrades).

d. Scalability – ability to easily add more tenants, ability to add more capacity for more tenants.

Some of these properties are more easily and effectively achieved with option #1 (separate servers or schemas for each tenant), such as Isolation and Administration. Other properties are more easily and effectively achieved with option #2 (discriminator column) such as Maintainability and Scalability. This is a gross generalisation of course; there are many solutions to this design problem each with many pros and cons.

Some inspiration may be gained from examining how Oracle Application Express achieves this goal: multi-tenant has been baked into the product, via its concept of Workspaces. Each tenant can be given their own workspace in APEX and are able to build and deploy applications in isolation from other workspaces. Internally, APEX maintains a unique security_group_id for each workspace. This works very well – a single Oracle database instance can serve thousands or tens of thousands of workspaces.

It should be noted that a benefit of pursuing Option #2 is that it does not necessarily preclude using Option #1 as well, should the need arise later on – for example, to provide more capacity or better performance in the presence of more demanding tenants. For this reason, plus the fact that it’s much easier to maintain and enhance an application for all users at once if they’re colocated, I prefer Option #2.
Continue Reading


APEX Plugin: Password Strength Estimator

I needed a simple password strength prompt for users when they need to create or change their password on my website. After a bit of Googling I found the “Low-Budget Password Strength Estimator” which is supposedly used by Dropbox, so you know it’s good ūüôā

This simple javascript library runs entirely within the client’s browser, and when presented with a candidate password, gives a score from 0 (very poor) to 4 (very good). It can also return extra feedback, including a warning message for poor passwords, as well as suggestions for making a password more secure.

preview-verypoor

So I’ve created a very simple Dynamic Action plugin (try the demo here) that allows you to add this functionality to any item on your page. You can specify a minimum length for the password, and can override the default messages for each score. You can also select whether or not the feedback warnings or suggestions are shown.

preview-poor

It seems to catch a lot of poor passwords, including ones comprising common words and names, and ones involving a simple sequence or repetition.

preview-good

preview-strong

Obviously it’s only really useful for password entry fields; but don’t use it on your Login page!

Download from: http://github.com/jeffreykemp/jk64-plugin-passwordstrength


APEX Reports: One Link, Multiple Destinations

Every Interactive Report has an optional set of “Link” attributes that allow you to specify the location where the user should be redirected if they click a link next to a record in the report. You can choose “Link to Custom Target” and use the Link Builder to easily specify the target application, page, item values to pass, and other attributes.

linkbuilder1

What if the report combines different entities, and you need to direct the user to a different page depending on the type of entity? Or, if you need to direct the user to a different page with different attributes depending on the status of the record?

One method is to generate the URL in the report query using apex_page.get_url (APEX 5+) or apex_util.prepare_url (APEX 4 or earlier), or (God forbid) you could generate the url yourself using string concatenation.

A more declarative solution is to instead use APEX page redirects. This solution involves the following:

  1. Add some hidden items to the page to store the parameters for each target page;
  2. Add a Branch to the page for each target page; and
  3. Add a Request to the link to signal the page that a redirect has been requested.

Here’s an example. My page 550 has an interactive report which combines TI records with TRQ records (both of which have a very similar structure). If the user clicks on a TI record they should be redirected to p510 with the corresponding TI_ID, and if they click on a TRQ record they should be redirected to p305 with the corresponding TRQ_ID.

Here’s the link attributes for this report:

linkbuilder2

Notice that the page now redirects back to itself with the request set to “GOTO_TARGET”, along with the IDs required. My report query has been constructed so that every record will only have a TI_ID or a TRQ_ID, never both at the same time; so the link will ensure that only one of the P550_GOTO_xxx_ID values will be set.

The page then just needs two Branches: one for each target. Conditions on each branch ensures they only get activated if the request has been set, and the branch is selected based on which “GOTO ID” item has been set:

branch1

branch2

For a normal navigation to this report (e.g. from another page), the request should be blank (or some other value) so none of the Branches should be triggered.

For a relatively simple scenario like this, I like the declarative approach. Each branch can take advantage of the full range of APEX features such as the link builder, security conditions, build options, etc.

Note: this method works just as well for Classic report links as well.

The thing to be mindful of is that the order of the branches, and the condition on each branch, must be carefully selected so that the correct branch is activated in each situation. I’ve shown a simple example which works because I have ensured that only one of the ID parameters is set at the same time. If a record has both IDs, the condition on the first branch “GOTO_TARGET (TI_ID)” will evaluate to True and it will be used, regardless of what GOTO_TRQ_ID was set to.

If there were numerous potential destination pages, with a large number of parameters to pass, I might choose the apex_page.get_url method instead.

Related


Show greyscale icon as red

I have an editable tabular form using APEX’s old greyscale edit link icons:

greyscale-icons

The users complained that they currently have to click each link to drill down to the detail records to find and fix any errors; they wanted the screen to indicate which detail records were already fine and which ones needed attention.

Since screen real-estate is limited here, I wanted to indicate the problems by showing a red edit link instead of the default greyscale one; since this application is using an old theme I didn’t feel like converting it to use Font Awesome (not yet, at least) and neither did I want to create a whole new image and upload it. Instead, I¬†tried a CSS trick to convert the greyscale image to a red shade.

I used this informative post to work out what I needed: http://css-tricks.com/color-filters-can-turn-your-gray-skies-blue/

WARNING: Unfortunately this trick does NOT work in IE (tested in IE11). Blast.

Firstly, I added a column to the underlying query that determines if the error needs to be indicated or not:

select ...,
       case when {error condition}
       then 'btnerr' end as year1_err
from mytable...

I set the new column type to Hidden Column.

The link column is rendered using a Link-type column, with Link Text set to:

<img src="#IMAGE_PREFIX#e2.gif" alt="">

I changed this to:

<img src="#IMAGE_PREFIX#e2.gif" alt="" class="#YEAR1_ERR#">

What this does is if there is an error for a particular record, the class "btnerr" is added to the img tag. Rows with no error will simply have class="" which does nothing.

Now, to make the greyscale image show up as red, I need to add an SVG filter to the HTML Header in the page:

<svg style="display:none"><defs>
  <filter id="redshader">
    <feColorMatrix type="matrix"
      values="0.7 0.7 0.7 0 0
              0.2 0.2 0.2 0 0
              0.2 0.2 0.2 0 0
              0   0   0   1 0"/>
  </filter>
</defs></svg>

I made up the values for the R G B lines with some trial and error. The filter is applied to the buttons with the btnerr class with this CSS in the Inline CSS property of the page:

img.btnerr {filter:url(#redshader);}

The result is quite effective:

greyscale-colorize

But, as I noted earlier, this solution does not work in IE, so that’s a big fail.

NOTE: if this application was using the Universal Theme I would simply apply a simple font color style to the icon since it would be using a font instead of an image icon.


Quick Pick in APEX Report

I have an Interactive Report that includes some editable columns, and the users wanted to include some “quick picks” on these columns to make it easy to copy data from a previous period. The user can choose to type in a new value, or click the “quick pick” to quickly data-enter the suggested value.

example-report-quickpick

Normally, a simple page item can have a quick pick by setting the Show Quick Picks attribute on the item. This is not, however, available as an option when generating APEX items in a report.

To do this, I added code like the following to my report query: NOTE: don’t copy this, refer to ADDENDUM below

SELECT ...
      ,APEX_ITEM.textarea(5,x.ytd_comments
         ,p_rows => 1
         ,p_cols => 30
         ,p_item_id => 'f05_'||to_char(rownum,'fm00000'))
       || case when x.prev_ytd_comments is not null
          then '<a href="javascript:$(''#'
            || 'f05_' || to_char(rownum,'fm00000')
            || ''').val('
            || apex_escape.js_literal(x.prev_ytd_comments)
            || ').trigger(''change'')">'
            || apex_escape.html(x.prev_ytd_comments)
            || '</a>'
          end
       as edit_ytd_comments
FROM my_report_view x;

This results in the following HTML code being generated:

html-report-quickpick

In the report definition, the EDIT_YTD_COMMENTS column has Escape Special Characters set to No. This runs a real risk of adding a XSS attack vector to your application, so be very careful to escape any user-entered data (such as prev_ytd_comments in the example above) before allowing it to be included. In this case, the user-entered data is rendered as the link text (so is escaped using APEX_ESCAPE.html) and also within some javascript (so is escaped using APEX_ESCAPE.js_literal).

So, if the data includes any characters that conflict with html or javascript, it is neatly escaped:

html-quickpick-bad

And it is shown on screen as expected, and clicking the link copies the data correctly into the item:

example-quickpick-bad

This technique should, of course, work with most of the different item types you can generate with APEX_ITEM.

Recommended further reading:

ADDENDUM 6/2/2017

A problem with the above code causes this to fail in Internet Explorer (IE11, at least) – when clicking on the quickpick, the user is presented with a page blank except for “[object Object]”. After googling I found this question on StackOverflow and fixed the problem by moving the jQuery code to a function defined at the page level.

I added this to the page Function and Global Variable Declaration:

function qp (id,v) {
  $(id).val(v).trigger('change');
}

And modified the report query as follows:

SELECT ...
      ,APEX_ITEM.textarea(5,x.ytd_comments
         ,p_rows => 1
         ,p_cols => 30
         ,p_item_id => 'f05_'||to_char(rownum,'fm00000'))
       || case when x.prev_ytd_comments is not null
          then '<a href="javascript:qp(''#'
            || 'f05_' || to_char(rownum,'fm00000')
            || ''','
            || apex_escape.js_literal(x.prev_ytd_comments)
            || ')">'
            || apex_escape.html(x.prev_ytd_comments)
            || '</a>'
          end
       as edit_ytd_comments
FROM my_report_view x;

Target=_Blank for Cards report template

cardsreport.PNGI wanted to use the “Cards” report template for a small report which lists file attachments. When the user clicks on one of the cards, the file should download and open in a new tab/window. Unfortunately, the Cards report template does not include a placeholder for extra attributes for the anchor tag, so it won’t let me add “target=_blank” like I would normally.

One solution is to edit the Cards template to add the extra placeholder; however, this means breaking the subscription from the universal theme.

As a workaround for this I’ve added a small bit of javascript to add the attribute after page load, and whenever the region is refreshed.

  • Set report static ID, e.g. “mycardsreport”
  • Add Dynamic Action:
    • Event = After Refresh
    • Selection Type = Region
    • Region = (the region)
  • Add True Action: Execute JavaScript Code
    • Code = $("#mycardsreport a.t-Card-wrap").attr("target","_blank"); (replace the report static ID in the selector)
    • Fire On Page Load = Yes

Note: this code affects all cards in the chosen report.