Adding a comment to a database field using JET

Question

I am working on a script to manage a small Access database online using the Jet engine in PHP. One thing I am having trouble doing is adding a comment to a field. This is quite easy using Access directly, but I can't figure out to do it programatically through an SQL statement or something similar. Any ideas? Thanks!

EDIT

I generally use MySQL, but Access provides a few benefits from time to time for smaller databases. Mostly, I can download and email them to people to use for whatever purpose they require.

I store timestamps as a long int rather than one of the built in types because it is easier to work with in PHP that way, and a lot easier to run a query against. I want to add a simple comment next to these timestamp fields that simply says something like Unix Timestamp so both the script and user know this as a timestamp rather than simply a number. I already know how to read comments, but can't seem to figure out how to write them when adding a new field.

I am using ADODB and Jet to interact with the database like so:

$conn = new COM('ADODB.Connection');
$conn->Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={$db};Mode=ReadWrite;");

Answer 1

You can get at the desciption with an ADOX Catalog, which, it seems, can be used with PHP

In VBA you could say:

catdb.ActiveConnection = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=" & CurrentProject.FullName

catdb.Tables("ATable").Columns("AColumn").Properties("Description") = "New descr"