<p>I try to open and excel reference in LabVIEW and then close it after sometime. But the LabVIEW keeps holding the reference and does not release it unless I close the VI. Why is this happening? Is there anyway to force it to release the Reference?</p>

<p>I am checking the error out for any errors. But it is not throwing up any errors.</p>

This might get you started. It will need some refinement
```
```
Table Product ( id PK, name, price, units_per_package)
Table Product_Attribs (id FK ref Product, AttribName, AttribValue)
```
```
Which would allow you to attach a list of attributes to the products. -- This is essentially your option 3
If you know a max number of attributes, You could go
```
```
Table Product (id PK, name, price, units_per_package, attrName_1, attrValue_1 ...)
```
```
Which would of course de-normalize the database, but make queries easier.
I prefer the first option because
It supports an arbitrary number of attributes.
Attribute names can be stored in another table, and referential integrity enforced so that those damn Canadians don't stick a "colour" in there and break reporting.