Installation guide

5. mxODBC Overview

mxODBC is structured as Python package to support interfaces to many different

ODBC managers and drivers. Each of these interfaces is accessible as subpackage

of the

mx.ODBC Python package, e.g. on Windows you'd normally use the

mx.ODBC.Windows subpackage to access the Windows ODBC manager; on Unix

this would typically be the

mx.ODBC.iODBC, mx.ODBC.unixODBC or the

mx.ODBC.DataDirect package depending on which of these Unix ODBC

managers you have installed.

Each of these subpackages behaves as if it were a separate Python database

interface, so you actually get more than just one interface with mxODBC. The

advantage over other Python database interfaces is that all subpackages share the

same logic and programming interfaces, so you don't have to change your

application logic when moving from one subpackage to another. This enables

programs to run (more or less) unchanged on Windows and Unix, for example.

As you may know, there is a standard for Python database interfaces, the Python

Database API Specification or Python DB-API for short. Marc-André Lemburg, the

author of the mxODBC package, is the editor of this specification, so great care is

taken to make mxODBC as compatible to the Python DB-API as possible.

5.1 mxODBC and the Python Database API

Specification

The mxODBC package tries to adhere to the Python DB API Version 2.0 in most

details. Many features of the old Python DB API 1.0

are still supported to maintain

backwards compatibility and simplify porting old Python applications to the new

interface.

5.1.1 Differences

Here is a list of minor differences between mxODBC and the DB API 2.0

specifications:

•

cursor.description doesn't return display_size and internal_size; both

values are always

None, since this information is not readily available

through ODBC interfaces used for result set processing, the information

can be expensive to determine and the values are not commonly used in

applications. If you do need to access this information, you can use the

cursor.getcolattribute() method with info ids

SQL.DESC_DISPLAY_SIZE and SQL.DESC_OCTET_LENGTH.