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| -rw-r--r-- | lib/sqlalchemy/dialects/mssql/base.py | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/lib/sqlalchemy/dialects/mssql/base.py b/lib/sqlalchemy/dialects/mssql/base.py index bc1ad5cdf..d1c7452a1 100644 --- a/lib/sqlalchemy/dialects/mssql/base.py +++ b/lib/sqlalchemy/dialects/mssql/base.py @@ -166,6 +166,26 @@ how SQLAlchemy handles this: This is an auxilliary use case suitable for testing and bulk insert scenarios. +MAX on VARCHAR / NVARCHAR +------------------------- + +SQL Server supports the special string "MAX" within the +:class:`.sqltypes.VARCHAR` and :class:`.sqltypes.NVARCHAR` datatypes, +to indicate "maximum length possible". The dialect currently handles this as +a length of "None" in the base type, rather than supplying a +dialect-specific version of these types, so that a base type +specified such as ``VARCHAR(None)`` can assume "unlengthed" behavior on +more than one backend without using dialect-specific types. + +To build a SQL Server VARCHAR or NVARCHAR with MAX length, use None:: + + my_table = Table( + 'my_table', metadata, + Column('my_data', VARCHAR(None)), + Column('my_n_data', NVARCHAR(None)) + ) + + Collation Support ----------------- |