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Diffstat (limited to 'doc/build/changelog/migration_11.rst')
| -rw-r--r-- | doc/build/changelog/migration_11.rst | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/doc/build/changelog/migration_11.rst b/doc/build/changelog/migration_11.rst index 81c438e06..ca6c44165 100644 --- a/doc/build/changelog/migration_11.rst +++ b/doc/build/changelog/migration_11.rst @@ -831,5 +831,41 @@ the same thing. :ticket:`3504` +.. _change_3434: + +The legacy_schema_aliasing flag is now set to False +--------------------------------------------------- + +SQLAlchemy 1.0.5 introduced the ``legacy_schema_aliasing`` flag to the +MSSQL dialect, allowing so-called "legacy mode" aliasing to be turned off. +This aliasing attempts to turn schema-qualified tables into aliases; +given a table such as:: + + account_table = Table( + 'account', metadata, + Column('id', Integer, primary_key=True), + Column('info', String(100)), + schema="customer_schema" + ) + +The legacy mode of behavior will attempt to turn a schema-qualified table +name into an alias:: + + >>> eng = create_engine("mssql+pymssql://mydsn", legacy_schema_aliasing=True) + >>> print(account_table.select().compile(eng)) + SELECT account_1.id, account_1.info + FROM customer_schema.account AS account_1 + +However, this aliasing has been shown to be unnecessary and in many cases +produces incorrect SQL. + +In SQLAlchemy 1.1, the ``legacy_schema_aliasing`` flag now defaults to +False, disabling this mode of behavior and allowing the MSSQL dialect to behave +normally with schema-qualified tables. For applications which may rely +on this behavior, set the flag back to True. + + +:ticket:`3434` + Dialect Improvements and Changes - Oracle ============================================= |