AutoCalcFields / Getting field values using Lazarus function
lazarus / 16-Databases

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Zomis · 2007-02-10 11:56

I see that the TDataSet class has an AutoCalcFields property. But I
have no idea if it works or not, or how to use it.

I want to use a Select-SQL Query which uses a field named "realcount"
which is defined using a Delphi function. The Delphi function needs a
"filename" field from the SQL Query, and then the Delphi function
returns "realcount" to the SQL Query. So for example, this table
Code: [Select]
filename       count        somedata
'test1.txt'      5       'just some data'
'test2.txt'      7       'another piece of data'

Using the SQL-query "select filename, count, realcount from mytable" I
want a Delphi function to open the file named filename, and scan that
file to check the "realcount" value which will be returned in the SQL-
query.

Is there somehow to do this using any kind of Database? (I'm using
SQLite right now, but I'm open for changes)

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Zomis · 2007-02-14 11:25

Sorry for putting "Delphi procedure" in the topic. Of course I meant
"Lazarus function"

And I have another idea about how this can be done, using custom SQL-
functions
Something like
SELECT filename,count,MyFunc(filename) FROM mytable

Is there any Databases which supports custom SQL-functions?