Is C++ OTL SQL database library using parameterized queries under the hood, or string concat?

Question

I\'ve been looking at the OTL (Oracle, Odbc and DB2-CLI Template Library) for C++ database access. I\'m unsure of whether the query I pass in is converted to a parameterize

Answer 1

OTL author's response to my e-mail:

OTL passes queries with placeholders into the DB API layers. The naming conventions for actual bind variables are different for different DB types. Say, for Oracle,

SELECT * FROM staff WHERE fname=:f_name

will be translated into:

SELECT * FROM staff WHERE fname=:f_name

plus a bunch of host variable bind calls.

For MS SQL Server, or DB2, the same SELECT would look like this:

SELECT * FROM staff WHERE fname=?

It's described in the manual that you can't have a placeholder with the same name more than once for MS SQL, DB2. SQL statements with placeholder / bind variables are relatively expensive to create, so if you instantiate an parameterized SQL via an otl_stream, it makes sense to reuse the stream as much as you can.

If you have more questions, or suggestions on how I can improve the OTL manual, feel free to email me.

Cheers, Sergei

pheadbaq wrote:

Hi, I've been evaluating C++ DB libraries recently to use as a base for an ORM library I wish to build, and have been gravitating more and more towards the OTL. It looks very nice by the way, and seems like it would meet most of the needs I have. I just have one lingering question that I can't seem to clarify by reading the docs. Does OTL pass a parameterized query on to the underlying DBMS, or is it concatenating the arguments and query I pass to the OTL stream into a single string and hand that to the DBMS?

In other words, if I hand OTL this MSSQL query, along with with the string "Bob" as the bind variable:

SELECT * FROM staff WHERE fname = :f_name

Does the OTL parser produce this:

SELECT * FROM staff WHERE fname = 'Bob'

Or this:

SELECT * FROM staff WHERE fname = @f_name

along with my string as a parameter

I've posted this same question to StackOverflow.com if you care to respond there: Is C++ OTL SQL database library using parameterized queries under the hood, or string concat?

Thank you for your time