Quanvert DSC: Limits and known problems

Quanvert DSC cannot read data for more than 2039 variables at once. For this calculation, you need to count the number of Quanvert variables, not the number of variables that are created in the UNICOM Intelligence Data Model. Each variable that is displayed in the Available Variables frame in Quanvert generally counts as one variable. However, some categorical and grid variables have numeric data associated with them and each of these variables counts as two variables.

This limit is most likely to be reached if you attempt to export all of the variables in a large Quanvert project. For example, when you use a "SELECT * FROM vdata" statement in a Data Management Script (DMS) file to export all of the variables in a large Quanvert project. However, the export should succeed if you change the SELECT statement to include fewer than 2040 Quanvert variables. You are unlikely to reach this limit in UNICOM Intelligence Reporter, unless you use variables that come from more than 2039 different Quanvert variables in the tables you are working on.

This problem can lead to incorrect data being retrieved from a Quanvert levels database, but is likely to be encountered only when you down-lev data in an SQL query. For example, if you run the following query against the Household sample Quanvert database that comes with the UNICOM Intelligence Developer Documentation Library, the Vehicle-level data is returned for the first person in each household only, whereas it should be returned for every person in each household for which there are any Vehicle-level cases.

For more information on hierarchical SQL queries, see Hierarchical SQL queries.

In UNICOM Intelligence Data Model 2.8.1 and later, Quanvert DSC provides support for "packed" Quanvert databases. However, there are a number of limitations:

▪Quanvert DSC can unpack no more than one .pkd file at the same time on the same computer. In a multiuser environment, this means that requests to unpack .pkd files are queued when necessary.

▪Quanvert DSC does not support packed projects that are split into more than one file. (These files typically have filename extensions .p01, .p02, and so on, with an index file with a filename extension of .pzz.)

▪Some Quanvert databases have an option to store variables in multiple subfolders. This option is controlled using a file called numdir.qv and was introduced because the 16-bit MS-DOS FAT file system is very slow when there are more than about 100 files in a folder. Quanvert DSC ignores this option when it is present in a packed project.

In UNICOM Intelligence Data Model 2.8 and earlier, Quanvert DSC does not support packed Quanvert projects and can read Quanvert data only if it has already been "unpacked". Quanvert includes a feature for unpacking packed projects. If you do not have Quanvert and are using an earlier version of the UNICOM Intelligence Data Model, you can use the qvtrans MS-DOS utility to unpack a Quanvert project. qvtrans is available from UNICOM Intelligence Support.

For more information, see Packed Quanvert projects.

An error occurs when converting a multi-punched grid question from Quanvert to other formats. Two possible solutions for this problem are:

▪When converting to DDF, use the MaxMultiCol=0 custom property on the DDF DSC. For more information, see Converting Quanvert data files into UNICOM Intelligence data files.