DBAPI returns natively the kinds of values we prefer:
- NUMBER values with positive precision + scale convert
to cx_oracle.STRING and then to Decimal. This
allows perfect precision for the Numeric type when
using cx_oracle. [ticket:1759]
- STRING/FIXED_CHAR now convert to unicode natively.
SQLAlchemy's String types then don't need to
apply any kind of conversions.
that tables with column names that overlap another column
of the form "<tablename>_<columnname>" won't produce
errors if column._label is used as a bind name during
an UPDATE. Test coverage which wasn't present in 0.5
has been added. [ticket:1755]
directly down to select().with_hint() and also accepts
entities as well as tables and aliases. See with_hint() in the
SQL section below. [ticket:921]
- Added with_hint() method to select() construct. Specify
a table/alias, hint text, and optional dialect name, and
"hints" will be rendered in the appropriate place in the
statement. Works for Oracle, Sybase, MySQL. [ticket:921]
using character counts, i.e. VARCHAR2(50 CHAR), so that
the column is sized in terms of characters and not bytes.
Column reflection of character types will also use
ALL_TAB_COLUMNS.CHAR_LENGTH instead of
ALL_TAB_COLUMNS.DATA_LENGTH. Both of these behaviors take
effect when the server version is 9 or higher - for
version 8, the old behaviors are used. [ticket:1744]
if the left side is a join, it will attempt to join the right
side to the rightmost side of the left first, and not raise
any exceptions about ambiguous join conditions if successful
even if there are further join targets across the rest of
the left. [ticket:1714]
- generalized the "freetds" / "unicode statements" behavior of MS-SQL/pyodbc
into the base Pyodbc connector, as this seems to apply to Sybase as well.
- generalized the python-sybase "use autocommit for DDL" into the pyodbc
connector. With pyodbc, the "autocommit" flag on connection is used,
as Pyodbc seems to have more database conversation than python-sybase that
can't otherwise be suppressed.
- Some platforms will now interpret certain literal values
as non-bind parameters, rendered literally into the SQL
statement. This to support strict SQL-92 rules that are
enforced by some platforms including MS-SQL and Sybase.
In this model, bind parameters aren't allowed in the
columns clause of a SELECT, nor are certain ambiguous
expressions like "?=?". When this mode is enabled, the base
compiler will render the binds as inline literals, but only across
strings and numeric values. Other types such as dates
will raise an error, unless the dialect subclass defines
a literal rendering function for those. The bind parameter
must have an embedded literal value already or an error
is raised (i.e. won't work with straight bindparam('x')).
Dialects can also expand upon the areas where binds are not
accepted, such as within argument lists of functions
(which don't work on MS-SQL when native SQL binding is used).
changes to Enum/SchemaType to re-support adaptation of string types.
This approach can be adapted by "conditional" unicode returning dialects
(i.e. pyodbc and possibly mxodbc) to remove the overhead
of isinstance(value, unicode) calls when the dialect returned type is
of dbapi.UNICODE, dbapi.NVARCHAR, etc.
Mike Bayer