Q: What are the requirements for installing QlikView?
Q: How much RAM do I need? Is there a simple way to relate RAM requirements to data volume?
A: No, it depends on the data structure and the type of data. The more rows of data and the wider each record is in terms of number of fields the more RAM is needed. If a field contains many different distinct values more RAM is required than if the number of distinct values is low. Certain charts may demand a large portion of RAM while being calculated.
Q: What is the theoretical limit of document size in QlikView?
A: It is impossible to translate this limit to a certain number of records (see question above). Typically QlikView uses 3-4 times as much memory during script execution as when working in the layout.
Q: I have 2 GB of RAM available but my 1 GB document gives me an “Out of memory“ error message when opening. What is wrong?
A: Each table in a QlikView document requires allocation of a contiguous chunk of memory. If memory is fragmented, e.g. by loaded dll’s, the allocation will fail and a correct error message will be shown. This behavior may vary between different computers.
Q: How large can documents be that are actually run in QlikView by real users?
A: When QlikView is run on a PC with say 512MB of RAM a few million rows of typical transaction data can be handled. In large servers with QlikView and several Gigabytes of RAM up to one billion rows (full transaction detail level without aggregation) are handled in customer applications at the time of writing (this information from May 2008 is 7 years old).
Scripts and Loading Data
Q: Is it possible to use more than one Binary statement in a QlikView script?
A: No, unfortunately not. Binary load uses very special logic to read the data already processed once into QlikView in another QlikView document. The "unpacking" used requires a "clean slate" in memory which is the reason why a Binary statement must be the very first statement in the script. Therefore it is also impossible to use Binary more than once in a script. However you can use QVD files to consolidate data from multiple QlikView documents at the same speed as with Binary.
Q: Is the only requirement for an automatic join that the field names are the same?
A: Yes! Such a join is called an association.
Q: Can I achieve an automatic join between two fields with different field names?
A: Yes, but you must rename one of the fields in the script using an ALIAS statement or an AS clause.
Q: Can I use Where clauses, Group by clauses and other SQL-like syntax on text files?
A: QlikView offers you a rich script language for text files including large parts of SQL syntax and a number of additional features.
Q: Can I use Where clauses, Group By clauses and other SQL-like syntax on binary QlikView files?
Q: What is the difference between an association between internal tables, a load or select statement preceded by a join qualifier, and a join within a select statement?
A: An association is a join between internal tables which is evaluated when you click on a field value in your document. QlikView makes this association automatically when two different tables have a field in common. The two latter joins are made during script execution and result in new logical tables. In these cases, QlikView does not load the original tables as logical tables.
Furthermore, a join within a select statement will usually only load those records whose key field value is found in both tables (inner join), whereas the two former joins also include records whose key field value is found in only one of the tables (full outer join).
Q: How do I load data from fix-record text files?
A: Use the table file wizard in QlikView.
Q: Can I update a QlikView document by loading only the data that have changed?
A: Yes, using incremental reloads.
Q: Can I read tables from web pages into QlikView?
A: Yes, the table file wizard makes it possible to extract tables when they are coded as tables in HTML. If the HTML page does not contain nicely formatted table tags it is still usually quite possible to extract data using e.g. the subfield and textbetween script functions.
Q: Why is it impossible to show frequency in certain list boxes?
A: The list box in which this problem occurs contains a field which is common to more than one internal table. It is therefore impossible for QlikView to know how to calculate frequency and other statistical entities for the field. It is also possible to solve the problem by loading the field an extra time from its main table (the one for which you want to show frequency), but under a new name, and show frequency for that field within the list box instead. By using the label feature, the end user does not have to notice the trick.
Q: Why does my statistics box come up with just a lot of n/a?
A: The statistics box contains a field which is common to more than one internal table. See the answer to the previous question.
Q: Why doesn't QlikView allow me to use a certain field in an expression in a chart?
A: The field is common to more than one internal table. See the answer to the two previous questions.
Q: How can I display the number of distinct values in a statistics box?
A: Use the distinct clause in your load / select statements.
Q: When is the AND mode option in the List Box Properties dialog enabled?
A: The AND mode option is only allowed under very strict conditions, imposed by the theory behind the QlikView logic. In order to enable the AND mode, the field must:
- exist in only one internal table,
- be the second field of only two fields in that table and
- contain no duplicate records.
- it must be proceeded by a distinct qualifier.
Q: Can I mix AND and OR logic for value selections within a list box?
A: No, the QlikView logic prohibits this.
Q: Can I have OR logic between list boxes?
A: Only indirectly. An advanced alternative is to use semantic links to transfer selections made in a list box to another field. Then change the selections in the original box and Ctrl-click on the semantic link to achieve OR between the two selections. The final result can be transferred by means of reversing the semantic link.
Q: Is it possible to link more than one info file to a value, e.g. a picture and a text file?
A: Yes, but only when duplicates of the field are used. Each field in QlikView can only be linked to one info file.
Q: Why are for instance '002', '02' and '2' sometimes interpreted as the same value by QlikView?
A: All the values in the example share the same numeric value in QlikView. As a rule, QlikView will try a numeric interpretation of any data. If a numeric interpretation is possible, it will be used for the association. If you use the interpretation function text() on a field in the script, however, the values will be treated strictly as text values. The values in the example above will then be interpreted as three different values.
Q: What is a "loop" or circular table structure?
A: When it is possible to follow the field associations in a never ending circle through the table structure, this is called a loop. Another way of describing the phenomenon is that there are two or more different routes through the table structure between two specific fields. Loops should be avoided as far as possible since they may cause ambiguities in the way data is interpreted. In many cases loops are a result of poor database design, but in other cases they may be unavoidable. QlikView will issue a warning if it finds a loop while executing the script and force you to resolve the problem with the help of loosely coupled tables.
Q: Why can't sheet objects without caption be sized at its upper end?
A: When you turn off the caption for a sheet object the upper border can only be used for moving the sheet object around, so instead use the upper corners of a sheet object to size.
Q: Why can't I expand my table to the right when I try to drag the border?
A: There are two handles on the right border of a table. If you drag the border of a table, you size the outer limits of what can be shown in the table. However, you can never make the outer frame larger than the sum of the widths of all columns in the table. The sizing of the rightmost column is made by putting the cursor just to the left of the outer border. Make sure that the outer frame does not fall in the middle of the column. If that is the case, use the scroll bar to position the column's right border at the outer frame. Use the design grid to see the actual outer frame of a sheet object.
Q: Can I change the name of a field in sheet objects in a QlikView document?
A: Yes, you can set a label for each field in each sheet object.
Q: Which sheet objects can be minimized?
A: All types of sheet objects can be minimized, but the option is set to off by default for sheet objects such as buttons, text objects and line/arrow objects.
Q: Can I move minimized objects on the sheet?
A: Yes, they can be moved freely and placed anywhere on the sheet and also sized within certain limits.
Sharing QlikView Documents with Other People
Q: Can I put my QlikView document on a server and share it with other people?
A: Yes, as long as the receivers have a registered QlikView license and access to the server directory.
Q: Can I use QlikView in real client/server mode?
A: Yes, you need a QlikView Server.
Q: Can I put my document as a link on a web page and let others access it over the net?
A: Yes, as long as the receivers have a registered QlikView license and access to the web page.
Q: Can I e-mail my document to other people?
A: Yes, as long as the receivers have a registered QlikView license.
Q: Can I prevent certain people from using my document?
A: Yes, using "Section Access" to define who may use the document.
Q: Can I prevent other people from seeing/changing the script?
A: Yes, the "Section Access" can give some people ADMIN access level while keeping other people off the script in USER access level.
Q: Where do I store information on access rights?
A: Information can be stored as a text file in a protected unit, or as a table in a database. It is also possible to store it as an inline statement in the script.
Q: Is there an automated way to create personalized copies to a large group of users?
A: Yes, you need a QlikView Publisher which is an add-on module to QlikView Server.