Reading dates from Sqlite with Delphi / Firedac

Question

When reading date fields from Sqlite into Firedac, I get conversion errors. The fields are called dates but with string entries (yyyy-mm-dd). I set the option for Datetime Format = string, but I've discovered that while null values are handled OK, empty values (= '') produce an error which I can't figure out how to handle.

Can you post some code? Sqllite stores dates as strings or integers, so you'll probably need to do some conversion. If we see some code, perhaps we can help.. — John Easley
Well, empty strings are not valid date strings. What should happen with them? — CL.

Victoria Victoria · Accepted Answer · 2017-09-23T13:28:12

You can enable StrsEmpty2Null option, which will automatically convert all empty strings to NULL state. But it's for all values and parameters handled by the data component. So it's not the cure.

I'm not sure what you're doing, but in general, NULL is a state and you cannot convert NULL state to a value because it's a state indicating no value. So as you cannot convert empty string to date.

So try to describe more about your value to string conversion, so we can suggest a proper way to deal with it. For SQLite, I'd suggest using DATE pseudo data type and convert values through the built-in formatting expressions.

Reading dates from Sqlite with Delphi / Firedac

1 Answers