sqlparams 1.0.0

Convert DB API 2.0 named parameters to ordinal parameters.

sqlparams: SQL Parameters

Introduction

sqlparams is a utility module for simplifying the use of SQL queries. Some Python DB API 2.0 compliant modules only support the ordinal qmark or format style parameters (e.g., pyodbc only supports qmark). This utility module provides a helper class, SQLParams, that is used to support named parameter styles such as named, numeric and pyformat, and have them safely converted to the desired ordinal style.

You first create an SQLParams instance specifying the named parameter style you’re converting from, and what ordinal style you’re converting to. Let’s convert from named to qmark style:

>>> import sqlparams
>>> query = sqlparams.SQLParams('named', 'qmark')

Now, lets to convert a simple SQL SELECT query using the format() method which accepts an SQL query, and a dictionary of parameters:

>>> sql, params = query.format('SELECT * FROM users WHERE name = :name;', {'name': "Thorin"})

This returns the new SQL query using ordinal qmark parameters with the corresponding list of ordinal parameters, which can be passed to the execute() method on a database cursor:

>>> print sql
SELECT * FROM users WHERE name = ?;
>>> print params
['Thorin']

Tuples are also supported which allows for safe use of the SQL IN operator:

>>> sql, params = query.format("SELECT * FROM users WHERE name IN :names;", {'names': ("Dori", "Nori", "Ori")})
>>> print sql
SELECT * FROM users WHERE name in (?,?,?);
>>> print params
['Dori', 'Nori', 'Ori']

You can also format multiple parameters for a single, shared query useful with the executemany() method of a database cursor:

>>> sql, manyparams = query.formatmany("UPDATE users SET age = :age WHERE name = :name;", [{'name': "Dwalin", 'age': 169}, {'name': "Balin", 'age': 178}])
>>> print sql
UPDATE users SET age = ? WHERE name = ?;
>>> print manyparams
[[169, 'Dwalin'], [178, 'Balin']]

Please note that if a tuple is used in formatmany(), the tuple must be the same size in each of the parameter lists. Otherwise, you might well use format() in a for-loop.

Source

The source code for sqlparams is available from the GitHub repo cpburnz/python-sql-parameters.

Installation

sqlparams can be installed from source with:

python setup.py install

sqlparams is also available for install through PyPI:

pip install sqlparams

Change History

1.0.0 (2012-12-20)

• Initial release.