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ODBC in C++: Need row count on SELECT query
Posted on 2007-11-21
When you prepare and execute a SQL statement, but before you fetch the results, is there any way to know how many rows there are in the result set? I need to create an array with the same number of elements.
Here's the application flow:
Execute SQL statement.
Bind columns to vars.
<-- I need the row count here so I can make an array of n elements.
Fetch rows.
The ODBC API has a function called SQLRowCount(), but MSDN says it only returns the number of rows affected by insert, update, or delete queries. It mentions nothing about select queries. I know I can read the entire result set to get the count, reset the cursor, and then read it again, but that is just inefficient.
Any ideas?
Here's the application flow:
Execute SQL statement.
Bind columns to vars.
<-- I need the row count here so I can make an array of n elements.
Fetch rows.
The ODBC API has a function called SQLRowCount(), but MSDN says it only returns the number of rows affected by insert, update, or delete queries. It mentions nothing about select queries. I know I can read the entire result set to get the count, reset the cursor, and then read it again, but that is just inefficient.
Any ideas?
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3 Comments
>>I need to create an array with the same number of elements.
I recommend using a vector container, so that you don't need to know the number of elements needed for the array.
A std::vector container will grow to the size you need it, as you add elements to it.
It's also a safer approach over using new or malloc, since the vector will automatically clean up the memory.
I recommend using a vector container, so that you don't need to know the number of elements needed for the array.
A std::vector container will grow to the size you need it, as you add elements to it.
It's also a safer approach over using new or malloc, since the vector will automatically clean up the memory.
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