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Foxpro Environment to MySQL in queries
Posted by: Jean Peter Paredes
Date: March 14, 2023 09:21PM

i am using Visual Foxpro and often times i extract parent tables from MySQL into a cursor in Visual Foxpro.

now the problem sometimes is that i needed to query a separate child table with matching ID from the Parent Table already in Visual Foxpro Environment which MySQL of course cant see cursors from that environment.

so what i would do normally is gather all the ID from the Parent table in Foxpro and put it in a variable that i can later use in my Query for the child table with the use of the "?varname" ... the issue with this is there might be a character limit in foxpro for variables and so bigger parent tables might have part of it not included in the variable.

next option, using foxpro i would create a temporary variable in MySQL, scan the parent table in foxpro and 1 by 1 concat the ID to the variable in MySQL to create a comma separated value of all parent IDs stored in a variable in MySQL, then in my Query for the child table i can filter it using FIND_IN_SET( @varname ) .. the problem is sometimes, depending on the size of the table, this is very SLOW.

so i would then try using IN as Select * from childtable where ID IN ( @varname ) but IN cannot seem to see some of the IDs in the comma separated value variable in mysql, there seems to be a limit.

tried also creating a temporary table in MySQL holding the filtered IDs from the Parent table then using Select * from childtable where ID IN ( select ID from tmpParentTable ) but this is also slow depending on data size.

i find that im running out of good options for an optimized way to filter result of a query for a Child Table in MySQL filtered by columns from a table that exists in Foxpro environment only.

any suggestions ?

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Foxpro Environment to MySQL in queries
March 14, 2023 09:21PM

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