General information
Category:
Coding, syntax & commands
Title:
Testing for existing relationship?
Is there a way in VFP6 to test for a relation that may or may not already exist?
I have a project where I have to pull data from an existing database that was built under FPW26 (still being used - all free tables). The database has a main table and many child tables that hold sports statistics for athletes in different sports. The main table has a field which indicates which table the stat data is in. There will never be more than three of the child tables in use at any one time. I need to be able to open the desired table and set a relation to it if it does not already have one. In the interest of speed, I would prefer not to tear down relations once established.
In the code segment below, I have marked with '->>' the line I would like to use, which gives me an error 'already engaged in a relation'.
Can I test to see if the relation exists and make the desired relation conditional?
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** Already in cursor c_Athlete created from main table **
pcSport0 = "reg_"+ ALLTRIM(gen_sc) && Identify main sport table
IF NOT USED (pcSport0)
USE (pcSport0) IN 0 ORDER registr_id && Open table if not already
ENDIF
select (pcSport0)
lnFieldCount0 = AFIELDS(aSport0Fields) && Copy table structure
CREATE CURSOR c_Sport0 FROM ARRAY aSport0Fields && to cursor
SELECT C_Sport0
INDEX ON registr_id TAG registr_id
->> SET RELATION TO registr_id into (pcsport0), registr_id into c_Sport0 IN c_Athlete ADDITIVE && Tie them together
* load record from sport0 table into cursor
SELECT (pcSport0)
...etc....
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Thanks,
Neil Preston
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