For starters, not like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.
When you concatenate strings, you cause problems because SQL receives commands like:
SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'
The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:
SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;
Which SQL sees as three separate commands:
SELECT * FROM MyTable WHERE StreetAddress = 'x';
A perfectly valid SELECT
DROP TABLE MyTable;
A perfectly valid "delete the table" command
And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.
So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?
After that, I have no idea what problem you are having: Metric is s
, which means it is a
- when you declare an array of value types, that create and allocates the space needed for each of the elements for you, just as an array of integers does. And your code doesn't create the array of
values at all, unless the external
variable has already created it, which would be weird since the loop since isn't known until that method is called.
But your SQL code ... it returns a single row. So what is the loop there for? Every time that method is called, it only puts data into the first element of the
array, and I have no idea what else you expected it to do...
If I'm honest, that doesn't look like a design you spent a lot of time thinking about: it looks like you leapt straight into code without much design - and it needs design in order to be coherent!