diff options
Diffstat (limited to 'lib/sqlalchemy/dialects/postgresql/psycopg2.py')
| -rw-r--r-- | lib/sqlalchemy/dialects/postgresql/psycopg2.py | 60 |
1 files changed, 1 insertions, 59 deletions
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py index b1d27c6fa..a52eacd8b 100644 --- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py +++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py @@ -323,57 +323,6 @@ on the way in and coerce from bytes on the way back, using the value of the SQLAlchemy's own unicode encode/decode functionality is steadily becoming obsolete as most DBAPIs now support unicode fully. -Bound Parameter Styles ----------------------- - -The default parameter style for the psycopg2 dialect is "pyformat", where -SQL is rendered using ``%(paramname)s`` style. This format has the limitation -that it does not accommodate the unusual case of parameter names that -actually contain percent or parenthesis symbols; as SQLAlchemy in many cases -generates bound parameter names based on the name of a column, the presence -of these characters in a column name can lead to problems. - -There are two solutions to the issue of a :class:`_schema.Column` -that contains -one of these characters in its name. One is to specify the -:paramref:`.schema.Column.key` for columns that have such names:: - - measurement = Table('measurement', metadata, - Column('Size (meters)', Integer, key='size_meters') - ) - -Above, an INSERT statement such as ``measurement.insert()`` will use -``size_meters`` as the parameter name, and a SQL expression such as -``measurement.c.size_meters > 10`` will derive the bound parameter name -from the ``size_meters`` key as well. - -.. versionchanged:: 1.0.0 - SQL expressions will use - :attr:`_schema.Column.key` - as the source of naming when anonymous bound parameters are created - in SQL expressions; previously, this behavior only applied to - :meth:`_schema.Table.insert` and :meth:`_schema.Table.update` - parameter names. - -The other solution is to use a positional format; psycopg2 allows use of the -"format" paramstyle, which can be passed to -:paramref:`_sa.create_engine.paramstyle`:: - - engine = create_engine( - 'postgresql://scott:tiger@localhost:5432/test', paramstyle='format') - -With the above engine, instead of a statement like:: - - INSERT INTO measurement ("Size (meters)") VALUES (%(Size (meters))s) - {'Size (meters)': 1} - -we instead see:: - - INSERT INTO measurement ("Size (meters)") VALUES (%s) - (1, ) - -Where above, the dictionary style is converted into a tuple with positional -style. - Transactions ------------ @@ -648,14 +597,7 @@ class PGExecutionContext_psycopg2(PGExecutionContext): class PGCompiler_psycopg2(PGCompiler): - def bindparam_string(self, name, **kw): - if "%" in name and not kw.get("post_compile", False): - # psycopg2 will not allow a percent sign in a - # pyformat parameter name even if it is doubled - kw["escaped_from"] = name - name = name.replace("%", "P") - - return PGCompiler.bindparam_string(self, name, **kw) + pass class PGIdentifierPreparer_psycopg2(PGIdentifierPreparer): |