Query set with Xbasic?

[abackstrom]

Hello,

I'm hoping to get some starter code for querying a set with Xbasic. I would like to do this from a standalone script, nothing tied to a form, and preferably all in Xbasic. (I believe Alpha has some sort of functionality for saving queries? I would like to sidestep that if possible.)

Generally I do this by setting query.filter and running <tbl>.query_create(), but from what I've seen so far there is no equivalent when working with sets. What are some ways of accomplishing this? (In my example, I want to query based on the child table in the set. The child table is linked via a 1-1 relationship.)

Thanks in advance.

[Stan Mathews]

Xbasic for querying a set

I've never used it to filter at the child level but I use this to order a set via xbasic.

s = set.open_session("sdivhist",FILE_RW_EXCLUSIVE)
t1 = s.item
t2 = s.divshist
query.order = "dcnum"
query.filter = ""
t1.query_create()

Might be a starting point.

You can also design the query in the operations tab, save it, the view/edit the xbasic. Here's a sample.

dim s as p 
s = set.open_session("sdivhist.set")
dim tbl as p 
tbl = s.table_get()
query.filter = "flattenquery("+"F04 = 3"+")"
query.order = "recno()"
query.options = ""
query.description = ""
tbl.query_create()
s.close()

[Finian Lennon]

You can create relationships with xbasic using <tbl>.relation_add() which is well documented in the help files. Once you've done this a couple of times you will only ever create a set when you must design a form or report to display your data and/or results.

For the example you cite, once you can create the one-to-one relationship with the child via tbl.relation_add(), you can query the child directly as this is possible with a one-to-one relationship. In the case of a one-to-many relationship, you can query the parent then parse the related children to obtain the info you need. I imagine this is what "Flatten_query" does behind the scenes.

Finian

[Tom Cone Jr]

Adam,

Here's a complete example for you, using a simple two table set, and a 1:1 link.

Unzip the attachment to an empty folder. Open the database, then choose the Code tab of the control panel. Then double click the only script you'll find there.

Hope this helps.

-- tom

[Finian Lennon]

Thanks to Tom for providing the sample adb.

Here's an example of the method I mentioned in my earleir message. It's the second script under the codes tab, Tom's is first.

The script is "self_contained" in that you could delete the set definition on which Tom's excellent example is based and the script would still do the "set" query.

Finian

[Finian Lennon]

I guess it would be more helpful if I attached the set ...