example on system fields

[#1]

What is the use of system fields? in which senario we use them? cam any one give me sample example on that?

yojas

[#2]

Hi,

System fields are internal predefined fields which contains important information about your document.

These are the system fields available in Qlikview.

$Table         it will show the names of the tables loaded in your application.

$Field         Displays the fields that are loaded from the tables.

$Fields     It will show the no. of fields in a table, you can select a table name in $table to see it.

$FieldNo     This list box shows the position of the fields in the tables.

$Rows         This list box shows the number of rows in the tables.

$Info         If info tables have been included in the document, their names will be displayed here.

Also, one important functionality of the system fields is when we use set hide prefix in qlikview. So that those fields even if selected are not displyed in the current selection box.

by default, hide prefix is '_', so if you name any field starting with _ then it will not be shown in your current selection box, as well as in the list of available fields, you need to check the show system fields then only those fields will be visible to you.

Best Regards,

Ashutosh

[#3]

Some more inputs:

• System fields are created during script execution.
• A very useful tool is the System table, a pivot table with the two dimensions $Field and $Table and the expression only($Field). To create system table, go to new sheet object -> system table
• main use of system fields is to get help to see how many total fields are there,how may tables are there,which field is present in which table, what are the no. of rows in the tables, what are the info fields there etc.

..

Ashutosh

[#4]

I tried to use '_' before date field but it shows error message.... how it works exactly?can you send me any example??

yojas

[jagannalla]

Where you are using '_' in script or in front end.

Can you explain lit bit clearly..

[#6 · Accepted solution]

set hideprefix = '%';

t1:

LOAD

day as _day,

price as $price,

1 as %test

Inline [

day, price

1, 100

2, 200 ];

Hi,

Use above script to see how set hide prefix works.

If you don't set this variable then I believe even putting _ will not hide the field.

Here, I have used % as hide prefix, so, %test will be hidden.

if you change it to _ then _day will be hidden.

There is also one more variable named hidesuffix which hides fields based on the suffix.

Please let me know, if any issue.

Please find the attached file.

..

Ashutosh

[#7]

Thanx for the Application......  now i undersatnd  how it works.....

yojas

[Anonymous]

Can I hide more than one prefix?

[#9]

i need to get the value from the system table from the database. what is the syntax. can you write the syntax instead of load script this will be help ful