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How to create neatly formatted Excel documents using PL/SQL?

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If there is a requirement to produce output from an application into Excel, you would probably create a CSV (Comma Separated File) with the data and start Excel to show the data - at least that's what I did...until now. The drawback of this solution is that you could only produce data and no nice layout. But Excel is also capable of opening HTML-files and using this you could create Excel files with data and magnificent layout! Let me give an example: 1. Create a procedure to show the data in formatted in an HTML table. CREATE OR REPLACE PROCEDURE display_emp_list IS v_emp_count NUMBER(5); v_empno NUMBER(8); v_ename VARCHAR2(50); v_job emp.job%TYPE; v_sal emp.sal%TYPE; v_bg_color VARCHAR2(10) := ''; CURSOR c_emp IS SELECT empno, initcap(ename), job, sal FROM emp ORDER BY ename; BEGIN SELECT COUNT(*) INTO v_emp_count FROM emp; owa_util.mime_header('application/ms-excel', FALSE); htp.p('Content...
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Refresh selected row(s) in an Interactive Grid

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In my previous post I blogged about pushing changed rows from the dabatase into an Interactive Grid . The use case I'll cover right here is probably more common - and therefore more useful! Until we had the IG, we showed the data in a report (Interactive or Classic). Changes to the data where made by popping up a form page, making changes, saving and refreshing the report upon closing the dialog. Or by clicking an icon / button / link in your report that makes some changes to the data (like changing a status) and ... refresh the report.  That all works fine, but the downsides are: The whole dataset is returned from the server to the client - again and again. And if your pagination size is large, that does lead to more and more network traffic, more interpretation by the browser and more waiting time for the end user. The "current record" might be out of focus after the refresh, especially by larger pagination sizes, as the first rows will be shown. Or (even wors...
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Stop using validations for checking constraints !

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 If you run your APEX application - like a Form based on the EMP table - and test if you can change the value of Department to something else then the standard values of 10, 20, 30 or 40, you'll get a nice error message like this: But it isn't really nice, is it? So what do a lot of developers do? They create a validation (just) in order to show a nicer, better worded, error message like "This is not a valid department".  And what you then just did is writing code twice : Once in the database as a (foreign key) check constraint and once as a sql statement in your validation. And we all know : writing code twice is usually not a good idea - and executing the same query twice is not enhancing your performance! So how can we transform that ugly error message into something nice? By combining two APEX features: the Error Handling Function and the Text Messages! Start with copying the example of an Error Handling Function from the APEX documentation. Create this function ...
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