Saturday, 29 August 2009

Using Dual

QlikView has a really cool data type called "Dual". This type allows you to mix text and numeric values which can be very useful.

For example, imagine that you had some pieces of text, say:

Apr, Aug, Dec, Feb, Jan, Jul, Jun, Mar, May, Nov, Oct, Sep

And you would prefer to have them sorted in another order, say:

Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec

Then we could load this something like:

Load
Dual(Name, Num) As Month;
LOAD * INLINE [
Num, Name
1, Jan
2, Feb
3, Mar
4, Apr
5, May
6, Jun
7, Jul
8, Aug
9, Sep
10, Oct
11, Nov
12, Dec
];

And the Month field would be sorted in the correct order.

If we need to get the component values spearately out of a Dual value, we can use Num and Text:

Text(Month) & ' (' & Num(Month) & ')'

Might give us a result of:

Apr (4)

Tuesday, 25 August 2009

Change the Command Centre port in v8.5

Thought that I might document this here while I still have an 8.5 server to play with.

Often, other applications will grab the ports that QVP processes use on your server (e.g. McAfee AV will often use 8081). To change the QVP ports there are a couple of places that you need to make changes.

In Program Files\Qlikview\ControlPanel, edit web.config and change the entry:

< add key="CommandCenterURL" value="http://localhost:8081/qtcc.asmx"/ >

to

< add key="CommandCenterURL" value="http://localhost:8765/qtcc.asmx"/ >

(I am using 8765 as the example port to change to).

In Program Files\Qlikview\CommandCenterService, edit QVPublisherCommandCenterService.exe.config and change the entry

< add key="WebservicePort" value="8081" / >

to

< add key="WebservicePort" value="8765" / >

Stop and start the services and you should be OK. You can always test the service on the server by calling the web service:

http://localhost:8765/qtcc.asmx

It should respond:

CommandCenterService v 2.0.50727.3082 says, "Hello world. The time is: 8/25/2009 14:39:39.8992663". For wsdl, add ?WSDL at the end of the request.

There are similar processes to change and/or test the other services:

Execution Service: http://localhost:8082/qtxs.asmx

or http://localhost:8082/debug

Directory Service: http://localhost:8083/qtds.asmx

Thursday, 20 August 2009

32bit ODBC/OLEDB on 64bit Server

This is something that I see questions about all the time. The quick answer is that QlikView 64bit cannot use a driver that is compiled for 32bits.

Why?

If I run an application on a 64bit server in 32bit mode, it has access to all the 32bit OLEDB/ODBC drivers. For example, I have a VBScript that generates OLEDB connection strings. If I run this using the %sysdir%\SysWOW64\csript.exe (the 32bit version of vbscript), I get the following list of OLEDB drivers:



I can see that the Microsoft Jet driver (for Access) is available.

However, when I run my VBScript application in 64bit mode, I get a different list:



No Access driver anymore!

The Microsoft Access drivers are old and have never been compiled for 64bits. This means that a 64bit application running on a Windows 64bit server cannot see them or use them.

QlikView 64bit is not a 32bit application that just runs on a 64bit server, it is an application that is fully compiled to operate in 64bits. I doesn't even know that the Access driver exists because Windows doesn't tell it about it.

So, the limitation is not to do with QlikView, it is a limitation of the company who have delivered the driver.

Luckily, most large database companies (Oracle 10g+, Teradata, Microsoft, etc.) have either OLEDB or ODBC drivers that work in 64bits.

If you just can't get your hands on a 32bit driver? Well, you could go down the route of installing 32bit QlikView client on your server (or another server?) and use that in Command Line mode to access the 32bit driver, read the data and store into QVDs that your 64bit publisher can read. This will of course consume one of your CALs or a developer license, so it is not idea.

The ideal solution is to see what you can do to get a 64bit version of the driver.

Wednesday, 19 August 2009

Google Maps QVW broken

The Google Maps example that comes with QlikView 9 has stopped working.

This is because Google have made a couple of changes. Luckily, it is resolveable.

Step 1:

Go to http://code.google.com/apis/maps/signup.html and sign up for a Google Maps API key.

This key, once you receive it, should be put into the document variable, gmap_key (the default value of "xx" will no longer work).

Step 2:

The .jpg that we need to put at the end of the URL so that QlikView knows the result is an image will break the URL because it is currently tagged onto the end of the API key. We need to add an additional '&' before the '.jpg' so that Google Maps can interpret the values correctly. It will ignore the "&.jpg" at the end.

- this appears to work OK (in the Colors tab of the Chart properies - Dynamic Image):

='http://maps.google.com/staticmap?center='
&
num(var_mid_lat, '##############', '.', ',' )
&
','
&
num(var_mid_long, '##############', '.', ',' )
&
'&zoom=$(var_zoom)'
&
'&size='&map_size_x&'x'&map_size_y
&
'&key='&gmap_key
&
'&maptype='&var_maptype
& '&.jpg'


Working fine for me now.

Tuesday, 18 August 2009

Very Useful YearToDate

Many people will have used YearToDate (or Year2Date) to calculate out whether the current date is Year to date for this year, last year, etc.:

YearToDate(date_value)

or

YearToDate(date_value, -1)

But there are some other values of YearToDate that make it very useful. The full syntax is:

YearToDate( date [ , yearoffset [ , firstmonth [ , todaydate] ] ] )

The third parameter is very useful because it allows us to use the one function for MonthToDate and QuarterToDate to compare Year-on-Year or dynamically change between YTD, MTD and QTD (there are functions InMonthToDate and InQuarterToDate that could be used but they would require different Year offset calculations and are less easy to make dynamic use of)

For example:

YearToDate(date_value, 0, Month(Today()))

gives us Month to date this year.

YearToDate(date_value, -1, Month(Today()))

gives us Month to date last year.

With a handy use of the Ceil function, we can also calculate Quarter to date:

Ceil(Month(Today())/3) * 3 - 2

This value will always return the first month of the quarter containing the Month number passed (in this case, Month(Today()) )

So, plugging this into our YearToDate:

YearToDate(date_value, 0, Ceil(Month(Today())/3) * 3 - 2 )

gives us Quarter to date.

YearToDate(date_value, -1, Ceil(Month(Today())/3) * 3 - 2 )

gives us Quarter to date last year.

Use of appropriate variables means that we can give the user a very useful dynamic swap between YTD, QTD and MTD - if that is required.

"=" sign in the expression builder

There is a very simple explanation for using the "=" sign in the expression builder - it tells QlikView to evaluate everything after the "=" and return the result.

Where there is some confusion is that within charts (and, in successive versions it has been removed in other places) the "=" is not necessary because it is assumed - you wouldn't put an expression in a chart unless you wanted it to be evaluated, would you?

In a text box, the need for the "=" becomes more apparent. If I add a Text Box to my layout and set the text expression to:

Sum(Sales)

Then the Text Box will come to the screen and have a value of "Sum(Sales)". This makes sense because the default interpretation of a Text Box should be that the values in the expression are just text. Now, if I add the "=" into the expression:

=Sum(Sales)

Then the calculation is performed and the result, the sum of all sales based on current selections in the document, is displayed in the Text Box.

It becomes more interesting when we use, or do not use, the "=" in a variable.

For example, if I set up 2 variables, vSales and vTotalSales.

vSales is going to have a value set up in the Expression Builder of:

Sum(Sales)

vTotalSales is going to have a value set up in the Builder of:

=Sum(Sales)

Now, if I set up a straight table and add a dimension, say "Year", and then add 2 expressions - one that is just $(vSales) and the other is $(vTotalSales), then the first column will show sales by Year and the second will show the same value in each row - the total sales for the document.

This happens because the first variable is simply a piece of text - "Sum(Sales)" - that is replaced into the chart expression and evaluated against each dimension. The "=" in the second variable causes it to be evaluated at the document level and it is the result rather than the expression that is inserted into the chart.

The "=" is also interesting in Dollar Expansion. We could achieve the same result as vTotalSales in the chart by using the expression:

$(=Sum(Sales))

This Sum(Sales) is now calculated outside the chart - i.e. at the document level - and the result, not the expression, is returned to the chart.

Knowing about the "=" sign in Expression Builder is very useful to avoid confusion and also to give you a new weapon in your arsenal.

Friday, 14 August 2009

Section Access Gotcha's

Couple of things that can cause you problems in Section Access:

- Loading Null values into the USERID field. You won't get back into your document!

- Loading mixed/lower case values into USERID and PASSWORD. Although they are not case sensitive for users entering them, they must be loaded in CAPITALS.

Monday, 10 August 2009

Sets =- or -=???

This question arose recently:

Note: Using gt and lt for Greater Than and Less Than symbols - sorry.

What is the difference between the set { lt Value = -{"X"} gt } and the set { lt Value -= {"X"} gt }?

Well the difference is that the first set is a modification of the $ set and saying that I want all values of the "Value" field excluding the value "X" (it could have also been written as { lt Value = {*}-{"X"} gt ).

The second set is different in that it is additive (or actually subtractive) - it will take whatever selections are on the "Value" field and take off the "X".

So, for the first one, if you make any selections on the "Value" field, they will be ignored. For the second one, your selections will be reflected in the result except if "X" is part of your selections it will be excluded.

As an example, take the following dataset:

Sales:
Load * Inline [
User, Sales
John, 12222
Tom, 11000
Jane, 19000
May, 21000
Graham, 13300
];

If I create a straight table with User as the dimension and the following 2 expressions:


Sum({ lt User = -{"John"} gt Sales)

Sum({ lt User -= {"John"} gt Sales)

Then whatever selection I make on User will not effect the result - the chart will list the sales for Time, Jane, May and Graham (no John). For the second, if I make selections on a user, the other users will zero out but I will still see no John.

Enjoy.

Days360

Recently a client asked me about the Excel function Days360. This is a commonly used function within the financial industry to calculate the number of days between two dates based on a 360 day year - i.e. 12 x 30day months.

The function in Excel takes 2 mandatory parameters and 1 optional parameter:

DAYS360(start_date,end_date,method)

If the "method" parameter is FALSE or left out, then it uses the US (NASD) method. If it is TRUE then it uses the European method. The difference is that in the European method if either the start or end date are on the 31st of the month, they are considered to be on the 30th of the month.

I have a simple VBScript function that replicates this functionality:


Function Days360(StartDate, EndDate, European)

Dim Days1, Days2
Days1 = Day(EndDate)
Days2 = Day(StartDate)

If European and Days1 = 31 Then Days1 = 30
If European and Days2 = 31 Then Days2 = 30

Days360 = DATEDIFF("m", StartDate, EndDate) * 30 + Days1 - Days2

End Function

Unfortunately VBScript doesn't have a MIN function or this could be reduced to be even simpler.

Now, if I define ths VBScript function in my QV Document, I can call it from within the load script in a QlikView application. Since version 8.2 though, I am unable to call macro functions from the chart so I have to have a different solution.

Oleg Troyansky gave a good formula for the month difference: http://community.qlikview.com/forums/p/9923/39894.aspx#39894

MonthDiff = (year(Date1)*12 + Month(Date1)) - (year(Date2)*12 + Month(Date2))

This works great for me. So, I now just need to add the days subtraction. This needs to be two separate functions, one for US and one for Europe.

US:

=(((YEAR(Date2)*12 + MONTH(Date2)) - (YEAR(Date1)*12 + MONTH(Date1))) * 30) + DAY(Date2) - DAY(Date1)

Europe (using the Nummin function to step back a 31st to 30th):

=(((YEAR(Date2)*12 + MONTH(Date2)) - (YEAR(Date1)*12 + MONTH(Date1))) * 30) + Nummin(DAY(Date2),30) - Nummin(DAY(Date1),30)

I hope that this helps others get past this one.


It is worth remembering. No matter what function that you come across that doesn't exist in QlikView, it has to be calcuable some way - and probably is do-able within QlikView.

Does it exist?

In QlikView, we have the option to check if a value is already in a field using the "Exists" clause. I have seen some confusion with it over time, so hopefully this will help.

Exists is an inter-record function that we can use within the load script to check for the existence of a value in a previously loaded field.

The syntax is as follows:

exists(field [, expression])

The field is a field that already exists in our document - which includes any fields in the current load statement.

The expression is a calculation based on the data that we are currently loading.

Note that expression is not a required field. If it is excluded, exists calculates if the value of the field exists in any previous loaded value for that field.

Here is a simple example of using Exists to only load data that exists in a previously loaded field.


Budget:
Load * Inline [
User, Budget
Tom, 10000
Jane, 20000
May, 22000
Graham, 12300
];

Sales:
Load * Inline [
User, Sales
Tom, 11000
Jane, 19000
May, 21000
Graham, 13300
John, 23456
]
Where Exists(User);

The first load statement loads budget information for users Tom, Jane, May and Graham. The second load statement brings in the sales values for users but we state that we only want values for users already exist.

In this case, no values will be loaded for John.

Here, we didn't need to pass an expression (although we could have done Exists(User,User)) because we were looking for a value in the same field that was being loaded.

Here is another example of a similar sales loader:


Sales:
Load
RowNo() As row,
User,
Sales,
If(Exists(User,User), 1, 0) As Exists
;
Load * Inline [
User, Sales
John, 12222
Tom, 11000
Jane, 19000
May, 21000
Graham, 13300
John, 23456
];

If we now put a table of values for row, user and exists, we would see that John in Row 1 has a 0 for exists and in row 6 he has a 1. This shows us that Exists is working on data that is loading in the current load statement also, not just on data that has been loaded before.

The Expression parameter of the Exists statement is very useful - especially if you have complex keys in an Load.