Convert DB API 2.0 named parameters to ordinal parameters.
Project description
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
1.0.1 (2012-12-20)
Fixed running test as a script.
1.0.0 (2012-12-20)
Initial release.
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