What is the equivalent Database Connectivity VI of the SQL Toolkit 'Set SQL Parameter to Null' VI ? 
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 What is the equivalent Database Connectivity VI of the SQL Toolkit 'Set SQL Parameter to Null' VI ?

I am using the database connectivity (ADO based) tool and I want to be
able to insert a null values.
I have included a simple VI that demonstrates how this works with SQL
toolkit .
Null values are very useful and occur frequently in dealing with data.
I wish that labview handled them much better - (e.g. there is not
datatype in LabVIEW corresponding to a Null value).


Tue, 28 Sep 2004 04:31:25 GMT  
 What is the equivalent Database Connectivity VI of the SQL Toolkit 'Set SQL Parameter to Null' VI ?
The VI was not attached but I'm going to answer with what I have here.
- Currently, the Database Toolset converts NULLs to the default value
for LabVIEW data types (ie, False for Boolean, empty strings, zero for
numbers, empty arrays, etc). In the user manual there is an example
that shows database records containing NULL values being first
converted to a string, empty strings (the NULLs) are then converted to
NaNs instead of the usual zero value. This method requires you to know
what data types each field contains and that they know what to look
for and how to convert the data.
You can go to this following link to suggest that a null datatype be
implemented:
https://sine.ni.com/apps/we/nicc.call_me?p_country=&p_lang_id=US&p_fo...

-Also you cannot leave parameters values empty because there is a big
difference between executing an SQL statement and doing a
Parameterized Query, especially when looking at the low-level ADO
layer.When doing Parameterized Queries, you MUST specify all parameter
values - leaving them empty results in ADO trapping errors rather than
using a default value.

Regards,
Cyril Bouton
Applications Engineer
National Instruments



Wed, 29 Sep 2004 04:53:28 GMT  
 
 [ 2 post ] 

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