[feature] [versioning] The "multiple heads / branches" feature has now landed. This is by far the most significant change Alembic has seen since its inception; while the workflow of most commands hasn't changed, and the format of version files and the alembic_version table are unchanged as well, a new suite of features opens up in the case where multiple version files refer to the same parent, or to the "base". Merging of branches, operating across distinct named heads, and multiple independent bases are now all supported. The feature incurs radical changes to the internals of versioning and traversal, and should be treated as "beta mode" for the next several subsequent releases within 0.7.

References: #167

[feature] [versioning] In conjunction with support for multiple independent bases, the specific version directories are now also configurable to include multiple, user-defined directories. When multiple directories exist, the creation of a revision file with no down revision requires that the starting directory is indicated; the creation of subsequent revisions along that lineage will then automatically use that directory for new files.

References: #124

[feature] [operations] [sqlite] Added "move and copy" workflow, where a table to be altered is copied to a new one with the new structure and the old one dropped, is now implemented for SQLite as well as all database backends in general using the new Operations.batch_alter_table() system. This directive provides a table-specific operations context which gathers column- and constraint-level mutations specific to that table, and at the end of the context creates a new table combining the structure of the old one with the given changes, copies data from old table to new, and finally drops the old table, renaming the new one to the existing name. This is required for fully featured SQLite migrations, as SQLite has very little support for the traditional ALTER directive. The batch directive is intended to produce code that is still compatible with other databases, in that the "move and copy" process only occurs for SQLite by default, while still providing some level of sanity to SQLite's requirement by allowing multiple table mutation operations to proceed within one "move and copy" as well as providing explicit control over when this operation actually occurs. The "move and copy" feature may be optionally applied to other backends as well, however dealing with referential integrity constraints from other tables must still be handled explicitly.

References: #21

[commands] [feature] Relative revision identifiers as used with alembic upgrade, alembic downgrade and alembic history can be combined with specific revisions as well, e.g. alembic upgrade ae10+3, to produce a migration target relative to the given exact version.

[bug] [commands] The alembic revision command accepts the --sql option to suit some very obscure use case where the revision_environment flag is set up, so that env.py is run when alembic revision is run even though autogenerate isn't specified. As this flag is otherwise confusing, error messages are now raised if alembic revision is invoked with both --sql and --autogenerate or with --sql without revision_environment being set.

References: #248

[autogenerate] [bug] [postgresql] Added a rule for Postgresql to not render a "drop unique" and "drop index" given the same name; for now it is assumed that the "index" is the implicit one Postgreql generates. Future integration with new SQLAlchemy 1.0 features will improve this to be more resilient.

References: #247

[autogenerate] [bug] A change in the ordering when columns and constraints are dropped; autogenerate will now place the "drop constraint" calls before the "drop column" calls, so that columns involved in those constraints still exist when the constraint is dropped.

References: #247

[commands] [feature] New commands added: alembic show, alembic heads and alembic merge. Also, a new option --verbose has been added to several informational commands, such as alembic history, alembic current, alembic branches, and alembic heads. alembic revision also contains several new options used within the new branch management system. The output of commands has been altered in many cases to support new fields and attributes; the history command in particular now returns it's "verbose" output only if --verbose is sent; without this flag it reverts to it's older behavior of short line items (which was never changed in the docs).

[changed] [commands] The --head_only option to the alembic current command is deprecated; the current command now lists just the version numbers alone by default; use --verbose to get at additional output.

[config] [feature] Added new argument Config.config_args, allows a dictionary of replacement variables to be passed which will serve as substitution values when an API-produced Config consumes the .ini file. Pull request courtesy Noufal Ibrahim.

[bug] [oracle] The Oracle dialect sets "transactional DDL" to False by default, as Oracle does not support transactional DDL.

References: #245

[autogenerate] [bug] Fixed a variety of issues surrounding rendering of Python code that contains unicode literals. The first is that the "quoted_name" construct that SQLAlchemy uses to represent table and column names as well as schema names does not repr() correctly on Py2K when the value contains unicode characters; therefore an explicit stringification is added to these. Additionally, SQL expressions such as server defaults were not being generated in a unicode-safe fashion leading to decode errors if server defaults contained non-ascii characters.

References: #243

[bug] [operations] The Operations.add_column() directive will now additionally emit the appropriate CREATE INDEX statement if the ~sqlalchemy.schema.Column object specifies index=True. Pull request courtesy David Szotten.

References: #174

[feature] [operations] The ~sqlalchemy.schema.Table object is now returned when the Operations.create_table() method is used. This Table is suitable for use in subsequent SQL operations, in particular the Operations.bulk_insert() operation.

References: #205

[autogenerate] [feature] Indexes and unique constraints are now included in the EnvironmentContext.configure.include_object hook. Indexes are sent with type "index" and unique constraints with type "unique_constraint".

References: #203

[autogenerate] [bug] Bound parameters are now resolved as "literal" values within the SQL expression inside of a CheckConstraint(), when rendering the SQL as a text string; supported for SQLAlchemy 0.8.0 and forward.

References: #219

[autogenerate] [bug] Added a workaround for SQLAlchemy issue #3023 (fixed in 0.9.5) where a column that's part of an explicit PrimaryKeyConstraint would not have its "nullable" flag set to False, thus producing a false autogenerate. Also added a related correction to MySQL which will correct for MySQL's implicit server default of '0' when a NULL integer column is turned into a primary key column.

References: #199

[autogenerate] [bug] [mysql] Repaired issue related to the fix for #208 and others; a composite foreign key reported by MySQL would cause a KeyError as Alembic attempted to remove MySQL's implicitly generated indexes from the autogenerate list.

References: #240

[autogenerate] [bug] If the "alembic_version" table is present in the target metadata, autogenerate will skip this also. Pull request courtesy Dj Gilcrease.

References: #28

[autogenerate] [bug] The EnvironmentContext.configure.version_table and EnvironmentContext.configure.version_table_schema arguments are now honored during the autogenerate process, such that these names will be used as the "skip" names on both the database reflection and target metadata sides.

References: #77

[autogenerate] [changed] The default value of the EnvironmentContext.configure.user_module_prefix parameter is no longer the same as the SQLAlchemy prefix. When omitted, user-defined types will now use the __module__ attribute of the type class itself when rendering in an autogenerated module.

References: #229

[bug] [templates] Revision files are now written out using the 'wb' modifier to open(), since Mako reads the templates with 'rb', thus preventing CRs from being doubled up as has been observed on windows. The encoding of the output now defaults to 'utf-8', which can be configured using a newly added config file parameter output_encoding.

References: #234

[bug] [operations] Added support for use of the ~sqlalchemy.sql.elements.quoted_name construct when using the schema argument within operations. This allows a name containing a dot to be fully quoted, as well as to provide configurable quoting on a per-name basis.

References: #230

[autogenerate] [bug] [postgresql] Added a routine by which the Postgresql Alembic dialect inspects the server default of INTEGER/BIGINT columns as they are reflected during autogenerate for the pattern nextval(<name>...) containing a potential sequence name, then queries pg_catalog to see if this sequence is "owned" by the column being reflected; if so, it assumes this is a SERIAL or BIGSERIAL column and the server default is omitted from the column reflection as well as any kind of server_default comparison or rendering, along with an INFO message in the logs indicating this has taken place. This allows SERIAL/BIGSERIAL columns to keep the SEQUENCE from being unnecessarily present within the autogenerate operation.

References: #73

[autogenerate] [bug] The system by which autogenerate renders expressions within a ~sqlalchemy.schema.Index, the server_default of ~sqlalchemy.schema.Column, and the existing_server_default of Operations.alter_column() has been overhauled to anticipate arbitrary SQLAlchemy SQL constructs, such as func.somefunction(), cast(), desc(), and others. The system does not, as might be preferred, render the full-blown Python expression as originally created within the application's source code, as this would be exceedingly complex and difficult. Instead, it renders the SQL expression against the target backend that's subject to the autogenerate, and then renders that SQL inside of a ~sqlalchemy.sql.expression.text() construct as a literal SQL string. This approach still has the downside that the rendered SQL construct may not be backend-agnostic in all cases, so there is still a need for manual intervention in that small number of cases, but overall the majority of cases should work correctly now. Big thanks to Carlos Rivera for pull requests and support on this.

References: #196, #197, #64

[feature] SQLAlchemy's testing infrastructure is now used to run tests. This system supports both nose and pytest and opens the way for Alembic testing to support any number of backends, parallel testing, and 3rd party dialect testing.

[changed] [compatibility] Minimum SQLAlchemy version is now 0.7.6, however at least 0.8.4 is strongly recommended. The overhaul of the test suite allows for fully passing tests on all SQLAlchemy versions from 0.7.6 on forward.

[bug] [operations] The "match" keyword is not sent to ForeignKeyConstraint by Operations.create_foreign_key() when SQLAlchemy 0.7 is in use; this keyword was added to SQLAlchemy as of 0.8.0.

[bug] [mssql] Fixed bug in MSSQL dialect where "rename table" wasn't using sp_rename() as is required on SQL Server. Pull request courtesy Łukasz Bołdys.

[feature] Added support for functional indexes when using the Operations.create_index() directive. Within the list of columns, the SQLAlchemy text() construct can be sent, embedding a literal SQL expression; the Operations.create_index() will perform some hackery behind the scenes to get the Index construct to cooperate. This works around some current limitations in Index which should be resolved on the SQLAlchemy side at some point.

References: #222

[bug] A file named __init__.py in the versions/ directory is now ignored by Alembic when the collection of version files is retrieved. Pull request courtesy Michael Floering.

References: #95

[bug] Fixed Py3K bug where an attempt would be made to sort None against string values when autogenerate would detect tables across multiple schemas, including the default schema. Pull request courtesy paradoxxxzero.

[bug] Autogenerate render will render the arguments within a Table construct using *[...] when the number of columns/elements is greater than 255. Pull request courtesy Ryan P. Kelly.

[bug] Fixed bug where foreign key constraints would fail to render in autogenerate when a schema name was present. Pull request courtesy Andreas Zeidler.

[bug] Some deep-in-the-weeds fixes to try to get "server default" comparison working better across platforms and expressions, in particular on the Postgresql backend, mostly dealing with quoting/not quoting of various expressions at the appropriate time and on a per-backend basis. Repaired and tested support for such defaults as Postgresql interval and array defaults.

References: #212

[enhancement] When a run of Alembic command line fails due to CommandError, the output now prefixes the string with "FAILED:", and the error is also written to the log output using log.error().

References: #209

[bug] Liberalized even more the check for MySQL indexes that shouldn't be counted in autogenerate as "drops"; this time it's been reported that an implicitly created index might be named the same as a composite foreign key constraint, and not the actual columns, so we now skip those when detected as well.

References: #208

[feature] Added a new accessor MigrationContext.config, when used in conjunction with a EnvironmentContext and Config, this config will be returned. Patch courtesy Marc Abramowitz.

[autogenerate] [bug] [mysql] This releases' "autogenerate index detection" bug, when a MySQL table includes an Index with the same name as a column, autogenerate reported it as an "add" even though its not; this is because we ignore reflected indexes of this nature due to MySQL creating them implicitly. Indexes that are named the same as a column are now ignored on MySQL if we see that the backend is reporting that it already exists; this indicates that we can still detect additions of these indexes but not drops, as we cannot distinguish a backend index same-named as the column as one that is user generated or mysql-generated.

References: #202

[environment] [feature] Added new feature EnvironmentContext.configure.transaction_per_migration, which when True causes the BEGIN/COMMIT pair to incur for each migration individually, rather than for the whole series of migrations. This is to assist with some database directives that need to be within individual transactions, without the need to disable transactional DDL entirely.

References: #201

[autogenerate] [bug] Fixed bug where the include_object() filter would not receive the original Column object when evaluating a database-only column to be dropped; the object would not include the parent Table nor other aspects of the column that are important for generating the "downgrade" case where the column is recreated.

References: #200

[bug] [environment] Fixed bug where EnvironmentContext.get_x_argument() would fail if the Config in use didn't actually originate from a command line call.

References: #195

[autogenerate] [bug] Fixed another bug regarding naming conventions, continuing from #183, where add_index() drop_index() directives would not correctly render the f() construct when the index contained a convention-driven name.

References: #194

[bug] [mssql] Added quoting to the table name when the special EXEC is run to drop any existing server defaults or constraints when the drop_column.mssql_drop_check or drop_column.mssql_drop_default arguments are used.

References: #186

[bug] [mysql] Added/fixed support for MySQL "SET DEFAULT" / "DROP DEFAULT" phrases, which will now be rendered if only the server default is changing or being dropped (e.g. specify None to alter_column() to indicate "DROP DEFAULT"). Also added support for rendering MODIFY rather than CHANGE when the column name isn't changing.

References: #103

[bug] Added support for the initially, match keyword arguments as well as dialect-specific keyword arguments to Operations.create_foreign_key().

tagsfeature

tickets163

Altered the support for "sourceless" migration files (e.g. only .pyc or .pyo present) so that the flag "sourceless=true" needs to be in alembic.ini for this behavior to take effect.

References: #190

[bug] [mssql] The feature that keeps on giving, index/unique constraint autogenerate detection, has even more fixes, this time to accommodate database dialects that both don't yet report on unique constraints, but the backend does report unique constraints as indexes. The logic Alembic uses to distinguish between "this is an index!" vs. "this is a unique constraint that is also reported as an index!" has now been further enhanced to not produce unwanted migrations when the dialect is observed to not yet implement get_unique_constraints() (e.g. mssql). Note that such a backend will no longer report index drops for unique indexes, as these cannot be distinguished from an unreported unique index.

References: #185

[bug] Extensive changes have been made to more fully support SQLAlchemy's new naming conventions feature. Note that while SQLAlchemy has added this feature as of 0.9.2, some additional fixes in 0.9.4 are needed to resolve some of the issues:

-   The `Operations` object now takes into account the naming
    conventions that are present on the `MetaData` object that's
    associated using `~.EnvironmentContext.configure.target_metadata`.
    When `Operations` renders a constraint directive like
    `ADD CONSTRAINT`, it now will make use of this naming convention
    when it produces its own temporary `MetaData` object.

-   Note however that the autogenerate feature in most cases generates
    constraints like foreign keys and unique constraints with the
    final names intact; the only exception are the constraints implicit
    with a schema-type like Boolean or Enum.  In most of these cases,
    the naming convention feature will not take effect for these constraints
    and will instead use the given name as is, with one exception....

-   Naming conventions which use the `"%(constraint_name)s"` token, that
    is, produce a new name that uses the original name as a component,
    will still be pulled into the naming convention converter and be
    converted.  The problem arises when autogenerate renders a constraint
    with it's already-generated name present in the migration file's source
    code, the name will be doubled up at render time due to the combination
    of #1 and #2.  So to work around this, autogenerate now renders these
    already-tokenized names using the new `Operations.f()` component.
    This component is only generated if **SQLAlchemy 0.9.4** or greater
    is in use.

Therefore it is highly recommended that an upgrade to Alembic 0.6.4 be accompanied by an upgrade of SQLAlchemy 0.9.4, if the new naming conventions feature is used.

References: #183

[bug] Suppressed IOErrors which can raise when program output pipe is closed under a program like head; however this only works on Python 2. On Python 3, there is not yet a known way to suppress the BrokenPipeError warnings without prematurely terminating the program via signals.

References: #160

[bug] Fixed bug where Operations.bulk_insert() would not function properly when Operations.inline_literal() values were used, either in --sql or non-sql mode. The values will now render directly in --sql mode. For compatibility with "online" mode, a new flag ~.Operations.bulk_insert.multiinsert can be set to False which will cause each parameter set to be compiled and executed with individual INSERT statements.

References: #179

[bug] [py3k] Fixed a failure of the system that allows "legacy keyword arguments" to be understood, which arose as of a change in Python 3.4 regarding decorators. A workaround is applied that allows the code to work across Python 3 versions.

References: #175

[feature] The command.revision() command now returns the Script object corresponding to the newly generated revision. From this structure, one can get the revision id, the module documentation, and everything else, for use in scripts that call upon this command. Pull request courtesy Robbie Coomber.

[bug] Added a workaround for when we call fcntl.ioctl() to get at TERMWIDTH; if the function returns zero, as is reported to occur in some pseudo-ttys, the message wrapping system is disabled in the same way as if ioctl() failed.

References: #172

[feature] Added new argument EnvironmentContext.configure.user_module_prefix. This prefix is applied when autogenerate renders a user-defined type, which here is defined as any type that is from a module outside of the sqlalchemy. hierarchy. This prefix defaults to None, in which case the EnvironmentContext.configure.sqlalchemy_module_prefix is used, thus preserving the current behavior.

References: #171

[bug] Added support for autogenerate covering the use case where Table objects specified in the metadata have an explicit schema attribute whose name matches that of the connection's default schema (e.g. "public" for Postgresql). Previously, it was assumed that "schema" was None when it matched the "default" schema, now the comparison adjusts for this.

References: #170

[bug] The compare_metadata() public API function now takes into account the settings for EnvironmentContext.configure.include_object, EnvironmentContext.configure.include_symbol, and EnvironmentContext.configure.include_schemas, in the same way that the --autogenerate command does. Pull request courtesy Roman Podoliaka.

[bug] Calling bulk_insert() with an empty list will not emit any commands on the current connection. This was already the case with --sql mode, so is now the case with "online" mode.

References: #168

[bug] Enabled schema support for index and unique constraint autodetection; previously these were non-functional and could in some cases lead to attribute errors. Pull request courtesy Dimitris Theodorou.

[bug] More fixes to index autodetection; indexes created with expressions like DESC or functional indexes will no longer cause AttributeError exceptions when attempting to compare the columns.

References: #164

[feature] The ScriptDirectory system that loads migration files from a versions/ directory now supports so-called "sourceless" operation, where the .py files are not present and instead .pyc or .pyo files are directly present where the .py files should be. Note that while Python 3.3 has a new system of locating .pyc/.pyo files within a directory called __pycache__ (e.g. PEP-3147), PEP-3147 maintains support for the "source-less imports" use case, where the .pyc/.pyo are in present in the "old" location, e.g. next to the .py file; this is the usage that's supported even when running Python3.3.

References: #163

[bug] Autogenerate for op.create_table() will not include a PrimaryKeyConstraint() that has no columns.

[bug] Fixed bug in the not-internally-used ScriptDirectory.get_base() method which would fail if called on an empty versions directory.

[bug] An almost-rewrite of the new unique constraint/index autogenerate detection, to accommodate a variety of issues. The emphasis is on not generating false positives for those cases where no net change is present, as these errors are the ones that impact all autogenerate runs:

-   Fixed an issue with unique constraint autogenerate detection where
    a named `UniqueConstraint` on both sides with column changes would
    render with the "add" operation before the "drop", requiring the
    user to reverse the order manually.

-   Corrected for MySQL's apparent addition of an implicit index
    for a foreign key column, so that it doesn't show up as "removed".
    This required that the index/constraint autogen system query the
    dialect-specific implementation for special exceptions.

-   reworked the "dedupe" logic to accommodate MySQL's bi-directional
    duplication of unique indexes as unique constraints, and unique
    constraints as unique indexes.  Postgresql's slightly different
    logic of duplicating unique constraints into unique indexes
    continues to be accommodated as well.  Note that a unique index
    or unique constraint removal on a backend that duplicates these may
    show up as a distinct "remove_constraint()" / "remove_index()" pair,
    which may need to be corrected in the post-autogenerate if multiple
    backends are being supported.

-   added another dialect-specific exception to the SQLite backend
    when dealing with unnamed unique constraints, as the backend can't
    currently report on constraints that were made with this technique,
    hence they'd come out as "added" on every run.

-   the `op.create_table()` directive will be auto-generated with
    the `UniqueConstraint` objects inline, but will not double them
    up with a separate `create_unique_constraint()` call, which may
    have been occurring.  Indexes still get rendered as distinct
    `op.create_index()` calls even when the corresponding table was
    created in the same script.

-   the inline `UniqueConstraint` within `op.create_table()` includes
    all the options like `deferrable`, `initially`, etc.  Previously
    these weren't rendering.

References: #157

[feature] [mssql] Added new argument mssql_drop_foreign_key to Operations.drop_column(). Like mssql_drop_default and mssql_drop_check, will do an inline lookup for a single foreign key which applies to this column, and drop it. For a column with more than one FK, you'd still need to explicitly use Operations.drop_constraint() given the name, even though only MSSQL has this limitation in the first place.

[bug] [mssql] The MSSQL backend will add the batch separator (e.g. "GO") in --sql mode after the final COMMIT statement, to ensure that statement is also processed in batch mode. Courtesy Derek Harland.

[bug] [mysql] Fixed bug where op.alter_column() in the MySQL dialect would fail to apply quotes to column names that had mixed casing or spaces.

References: #152

[feature] Expanded the size of the "slug" generated by "revision" to 40 characters, which is also configurable by new field truncate_slug_length; and also split on the word rather than the character; courtesy Frozenball.

[bug] Fixed the output wrapping for Alembic message output, so that we either get the terminal width for "pretty printing" with indentation, or if not we just output the text as is; in any case the text won't be wrapped too short.

References: #135

[bug] Fixes to Py3k in-place compatibity regarding output encoding and related; the use of the new io.* package introduced some incompatibilities on Py2k. These should be resolved, due to the introduction of new adapter types for translating from io.* to Py2k file types, StringIO types. Thanks to Javier Santacruz for help with this.

[bug] Fixed py3k bug where the wrong form of next() was being called when using the list_templates command. Courtesy Chris Wilkes.

References: #145

[feature] Support for autogeneration detection and rendering of indexes and unique constraints has been added. The logic goes through some effort in order to differentiate between true unique constraints and unique indexes, where there are some quirks on backends like Postgresql. The effort here in producing the feature and tests is courtesy of IJL.

References: #107

[bug] Fixed bug introduced by new include_object argument where the inspected column would be misinterpreted when using a user-defined type comparison function, causing a KeyError or similar expression-related error. Fix courtesy Maarten van Schaik.

[bug] Added the "deferrable" keyword argument to op.create_foreign_key() so that DEFERRABLE constraint generation is supported; courtesy Pedro Romano.

[bug] Ensured that strings going to stdout go through an encode/decode phase, so that any non-ASCII characters get to the output stream correctly in both Py2k and Py3k. Also added source encoding detection using Mako's parse_encoding() routine in Py2k so that the doc of a non-ascii revision file can be treated as unicode in Py2k.

References: #137

[feature] Added new kw argument to EnvironmentContext.configure() include_object. This is a more flexible version of the include_symbol argument which allows filtering of columns as well as tables from the autogenerate process, and in the future will also work for types, constraints and other constructs. The fully constructed schema object is passed, including its name and type as well as a flag indicating if the object is from the local application metadata or is reflected.

References: #101

[feature] The output of the alembic history command is now expanded to show information about each change on multiple lines, including the full top message, resembling the formatting of git log.

[feature] Added alembic.config.Config.cmd_opts attribute, allows access to the argparse options passed to the alembic runner.

[feature] Added new command line argument -x, allows extra arguments to be appended to the command line which can be consumed within an env.py script by looking at context.config.cmd_opts.x, or more simply a new method EnvironmentContext.get_x_argument().

References: #120

[bug] Added support for options like "name" etc. to be rendered within CHECK constraints in autogenerate. Courtesy Sok Ann Yap.

References: #125

[misc] Source repository has been moved from Mercurial to Git.

[bug] Repaired autogenerate rendering of ForeignKeyConstraint to include use_alter argument, if present.

[feature] Added -r argument to alembic history command, allows specification of [start]:[end] to view a slice of history. Accepts revision numbers, symbols "base", "head", a new symbol "current" representing the current migration, as well as relative ranges for one side at a time (i.e. -r-5:head, -rcurrent:+3). Courtesy Atsushi Odagiri for this feature.

[feature] Source base is now in-place for Python 2.6 through 3.3, without the need for 2to3. Support for Python 2.5 and below has been dropped. Huge thanks to Hong Minhee for all the effort on this!

References: #55

[feature] Added version_table_schema argument to EnvironmentContext.configure(), complements the version_table argument to set an optional remote schema for the version table. Courtesy Christian Blume.

References: #76

[bug] [postgresql] Fixed format of RENAME for table that includes schema with Postgresql; the schema name shouldn't be in the "TO" field.

References: #32

[feature] Added output_encoding option to EnvironmentContext.configure(), used with --sql mode to apply an encoding to the output stream.

References: #90

[feature] Added Operations.create_primary_key() operation, will genenerate an ADD CONSTRAINT for a primary key.

References: #93

[bug] [mssql] Fixed bug whereby double quoting would be applied to target column name during an sp_rename operation.

References: #109

[bug] [mysql] [sqlite] transactional_ddl flag for SQLite, MySQL dialects set to False. MySQL doesn't support it, SQLite does but current pysqlite driver does not.

References: #112

[feature] upgrade and downgrade commands will list the first line of the docstring out next to the version number. Courtesy Hong Minhee.

References: #115

[feature] Added --head-only option to "alembic current", will print current version plus the symbol "(head)" if this version is the head or not. Courtesy Charles-Axel Dein.

[bug] Autogenerate will render additional table keyword arguments like "mysql_engine" and others within op.create_table().

References: #110

[feature] The rendering of any construct during autogenerate can be customized, in particular to allow special rendering for user-defined column, constraint subclasses, using new render_item argument to EnvironmentContext.configure().

References: #108

[bug] Fixed bug whereby create_index() would include in the constraint columns that are added to all Table objects using events, externally to the generation of the constraint. This is the same issue that was fixed for unique constraints in version 0.3.2.

[bug] Worked around a backwards-incompatible regression in Python3.3 regarding argparse; running "alembic" with no arguments now yields an informative error in py3.3 as with all previous versions. Courtesy Andrey Antukh.

[change] SQLAlchemy 0.6 is no longer supported by Alembic - minimum version is 0.7.3, full support is as of 0.7.9.

[bug] A host of argument name changes within migration operations for consistency. Keyword arguments will continue to work on the old name for backwards compatibility, however required positional arguments will not:

Operations.alter_column() - name -> new_column_name - old name will work for backwards compatibility.

Operations.create_index() - tablename -> table_name - argument is positional.

Operations.drop_index() - tablename -> table_name - old name will work for backwards compatibility.

Operations.drop_constraint() - tablename -> table_name - argument is positional.

Operations.drop_constraint() - type -> type_ - old name will work for backwards compatibility

References: #104

[autogenerate] [bug] Fixed bug where autogenerate would fail if a Column to be added to a table made use of the ".key" paramter.

References: #99

[bug] [sqlite] The "implicit" constraint generated by a type such as Boolean or Enum will not generate an ALTER statement when run on SQlite, which does not support ALTER for the purpose of adding/removing constraints separate from the column def itself. While SQLite supports adding a CHECK constraint at the column level, SQLAlchemy would need modification to support this. A warning is emitted indicating this constraint cannot be added in this scenario.

References: #98

[bug] Added a workaround to setup.py to prevent "NoneType" error from occuring when "setup.py test" is run.

References: #96

[bug] Added an append_constraint() step to each condition within test_autogenerate:AutogenRenderTest.test_render_fk_constraint_kwarg if the SQLAlchemy version is less than 0.8, as ForeignKeyConstraint does not auto-append prior to 0.8.

References: #96

[feature] Added a README.unittests with instructions for running the test suite fully.

References: #96

[bug] Added support for autogenerate render of ForeignKeyConstraint options onupdate, ondelete, initially, and deferred.

References: #92

[bug] Autogenerate will include "autoincrement=False" in the rendered table metadata if this flag was set to false on the source Column object.

References: #94

[feature] Explicit error message describing the case when downgrade --sql is used without specifying specific start/end versions.

References: #66

[bug] Removed erroneous "emit_events" attribute from operations.create_table() documentation.

References: #81

[bug] Fixed the minute component in file_template which returned the month part of the create date.

[feature] Support for tables in alternate schemas has been added fully to all operations, as well as to the autogenerate feature. When using autogenerate, specifying the flag include_schemas=True to Environment.configure() will also cause autogenerate to scan all schemas located by Inspector.get_schema_names(), which is supported by some (but not all) SQLAlchemy dialects including Postgresql. Enormous thanks to Bruno Binet for a huge effort in implementing as well as writing tests. .

References: #33

[feature] The command line runner has been organized into a reusable CommandLine object, so that other front-ends can re-use the argument parsing built in.

References: #70

[feature] Added "stdout" option to Config, provides control over where the "print" output of commands like "history", "init", "current" etc. are sent.

References: #43

[bug] Fixed the "multidb" template which was badly out of date. It now generates revision files using the configuration to determine the different upgrade_<xyz>() methods needed as well, instead of needing to hardcode these. Huge thanks to BryceLohr for doing the heavy lifting here.

References: #71

[bug] Fixed the regexp that was checking for .py files in the version directory to allow any .py file through. Previously it was doing some kind of defensive checking, probably from some early notions of how this directory works, that was prohibiting various filename patterns such as those which begin with numbers.

References: #72

[bug] Fixed MySQL rendering for server_default which didn't work if the server_default was a generated SQL expression. Courtesy Moriyoshi Koizumi.

[feature] Added support for alteration of MySQL columns that have AUTO_INCREMENT, as well as enabling this flag. Courtesy Moriyoshi Koizumi.

[feature] Added include_symbol option to EnvironmentContext.configure(), specifies a callable which will include/exclude tables in their entirety from the autogeneration process based on name.

References: #27

[feature] Added year, month, day, hour, minute, second variables to file_template.

References: #59

[feature] Added 'primary' to the list of constraint types recognized for MySQL drop_constraint().

[feature] Added --sql argument to the "revision" command, for the use case where the "revision_environment" config option is being used but SQL access isn't desired.

[bug] Repaired create_foreign_key() for self-referential foreign keys, which weren't working at all.

[bug] 'alembic' command reports an informative error message when the configuration is missing the 'script_directory' key.

References: #63

[bug] Fixes made to the constraints created/dropped alongside so-called "schema" types such as Boolean and Enum. The create/drop constraint logic does not kick in when using a dialect that doesn't use constraints for these types, such as postgresql, even when existing_type is specified to alter_column(). Additionally, the constraints are not affected if existing_type is passed but type_ is not, i.e. there's no net change in type.

References: #62

[bug] Improved error message when specifiying non-ordered revision identifiers to cover the case when the "higher" rev is None, improved message overall.

References: #66

[bug] Fixed issue whereby reflected server defaults wouldn't be quoted correctly; uses repr() now.

References: #31

[bug] Fixed issue whereby when autogenerate would render create_table() on the upgrade side for a table that has a Boolean type, an unnecessary CheckConstraint() would be generated.

References: #58

[feature] Implemented SQL rendering for CheckConstraint() within autogenerate upgrade, including for literal SQL as well as SQL Expression Language expressions.

[feature] Basic support for Oracle added, courtesy shgoh.

References: #40

[feature] Added support for UniqueConstraint in autogenerate, courtesy Atsushi Odagiri

[bug] Fixed support of schema-qualified ForeignKey target in column alter operations, courtesy Alexander Kolov.

[bug] Fixed bug whereby create_unique_constraint() would include in the constraint columns that are added to all Table objects using events, externally to the generation of the constraint.

[bug] bulk_insert() fixes:

-   bulk_insert() operation was
    not working most likely since the 0.2 series
    when used with an engine.

-   Repaired bulk_insert() to complete when
    used against a lower-case-t table and executing
    with only one set of parameters, working
    around SQLAlchemy bug #2461 in this regard.

-   bulk_insert() uses "inline=True" so that phrases
    like RETURNING and such don't get invoked for
    single-row bulk inserts.

-   bulk_insert() will check that you're passing
    a list of dictionaries in, raises TypeError
    if not detected.

References: #41

[general] The focus of 0.3 is to clean up and more fully document the public API of Alembic, including better accessors on the MigrationContext and ScriptDirectory objects. Methods that are not considered to be public on these objects have been underscored, and methods which should be public have been cleaned up and documented, including:

MigrationContext.get_current_revision() ScriptDirectory.iterate_revisions() ScriptDirectory.get_current_head() ScriptDirectory.get_heads() ScriptDirectory.get_base() ScriptDirectory.generate_revision()

[feature] Added a bit of autogenerate to the public API in the form of the function alembic.autogenerate.compare_metadata.

[feature] Informative error message when op.XYZ directives are invoked at module import time.

[bug] Fixed inappropriate direct call to util.err() and therefore sys.exit() when Config failed to locate the config file within library usage.

References: #35

[bug] Autogenerate will emit CREATE TABLE and DROP TABLE directives according to foreign key dependency order.

[bug] implement 'tablename' parameter on drop_index() as this is needed by some backends.

[feature] Added execution_options parameter to op.execute(), will call execution_options() on the Connection before executing.

The immediate use case here is to allow access to the new no_parameters option in SQLAlchemy 0.7.6, which allows some DBAPIs (psycopg2, MySQLdb) to allow percent signs straight through without escaping, thus providing cross-compatible operation with DBAPI execution and static script generation.

[bug] setup.py won't install argparse if on Python 2.7/3.2

[feature] script_location can be interpreted by pkg_resources.resource_filename(), if it is a non-absolute URI that contains colons. This scheme is the same one used by Pyramid.

References: #29

[feature] added missing support for onupdate/ondelete flags for ForeignKeyConstraint, courtesy Giacomo Bagnoli

[bug] fixed a regression regarding an autogenerate error message, as well as various glitches in the Pylons sample template. The Pylons sample template requires that you tell it where to get the Engine from now. courtesy Marcin Kuzminski

References: #30

[bug] drop_index() ensures a dummy column is added when it calls "Index", as SQLAlchemy 0.7.6 will warn on index with no column names.

[bug] Fixed the generation of CHECK constraint, regression from 0.2.0

References: #26

[feature] API rearrangement allows everything Alembic does to be represented by contextual objects, including EnvironmentContext, MigrationContext, and Operations. Other libraries and applications can now use things like "alembic.op" without relying upon global configuration variables. The rearrangement was done such that existing migrations should be OK, as long as they use the pattern of "from alembic import context" and "from alembic import op", as these are now contextual objects, not modules.

References: #19

[feature] The naming of revision files can now be customized to be some combination of "rev id" and "slug", the latter of which is based on the revision message. By default, the pattern "<rev>_<slug>" is used for new files. New script files should include the "revision" variable for this to work, which is part of the newer script.py.mako scripts.

References: #24

[bug] env.py templates call connection.close() to better support programmatic usage of commands; use NullPool in conjunction with create_engine() as well so that no connection resources remain afterwards.

References: #25

[bug] fix the config.main() function to honor the arguments passed, remove no longer used "scripts/alembic" as setuptools creates this for us.

References: #22

[bug] Fixed alteration of column type on MSSQL to not include the keyword "TYPE".

[feature] Can create alembic.config.Config with no filename, use set_main_option() to add values. Also added set_section_option() which will add sections.

References: #23

[bug] Clean up file write operations so that file handles are closed.

[feature] PyPy is supported.

[feature] Python 2.5 is supported, needs future.with_statement

[bug] Fix autogenerate so that "pass" is generated between the two comments if no net migrations were present.

[bug] Fix autogenerate bug that prevented correct reflection of a foreign-key referenced table in the list of "to remove".

References: #16

[bug] Fix bug where create_table() didn't handle self-referential foreign key correctly

References: #17

[bug] Default prefix for autogenerate directives is "op.", matching the mako templates.

References: #18

[feature] Add alembic_module_prefix argument to configure() to complement sqlalchemy_module_prefix.

References: #18

[bug] fix quotes not being rendered in ForeignKeConstraint during autogenerate

References: #14

Initial release. Status of features:

Alembic is used in at least one production environment, but should still be considered ALPHA LEVEL SOFTWARE as of this release, particularly in that many features are expected to be missing / unimplemented. Major API changes are not anticipated but for the moment nothing should be assumed.

The author asks that you please report all issues, missing features, workarounds etc. to the bugtracker.

Python 3 is supported and has been tested.

The "Pylons" and "MultiDB" environment templates have not been directly tested - these should be considered to be samples to be modified as needed. Multiple database support itself is well tested, however.

Postgresql and MS SQL Server environments have been tested for several weeks in a production environment. In particular, some involved workarounds were implemented to allow fully-automated dropping of default- or constraint-holding columns with SQL Server.

MySQL support has also been implemented to a basic degree, including MySQL's awkward style of modifying columns being accommodated.

Other database environments not included among those three have not been tested, at all. This includes Firebird, Oracle, Sybase. Adding support for these backends should be straightforward. Please report all missing/ incorrect behaviors to the bugtracker! Patches are welcome here but are optional - please just indicate the exact format expected by the target database.

SQLite, as a backend, has almost no support for schema alterations to existing databases. The author would strongly recommend that SQLite not be used in a migration context - just dump your SQLite database into an intermediary format, then dump it back into a new schema. For dev environments, the dev installer should be building the whole DB from scratch. Or just use Postgresql, which is a much better database for non-trivial schemas. Requests for full ALTER support on SQLite should be reported to SQLite's bug tracker at http://www.sqlite.org/src/wiki?name=Bug+Reports, as Alembic will not be implementing the "rename the table to a temptable then copy the data into a new table" workaround. Note that Alembic will at some point offer an extensible API so that you can implement commands like this yourself.

Well-tested directives include add/drop table, add/drop column, including support for SQLAlchemy "schema" types which generate additional CHECK constraints, i.e. Boolean, Enum. Other directives not included here have not been strongly tested in production, i.e. rename table, etc.

Both "online" and "offline" migrations, the latter being generated SQL scripts to hand off to a DBA, have been strongly production tested against Postgresql and SQL Server.

Modify column type, default status, nullable, is functional and tested across PG, MSSQL, MySQL, but not yet widely tested in production usage.

Many migrations are still outright missing, i.e. create/add sequences, etc. As a workaround, execute() can be used for those which are missing, though posting of tickets for new features/missing behaviors is strongly encouraged.

Autogenerate feature is implemented and has been tested, though only a little bit in a production setting. In particular, detection of type and server default changes are optional and are off by default; they can also be customized by a callable. Both features work but can have surprises particularly the disparity between BIT/TINYINT and boolean, which hasn't yet been worked around, as well as format changes performed by the database on defaults when it reports back. When enabled, the PG dialect will execute the two defaults to be compared to see if they are equivalent. Other backends may need to do the same thing.

The autogenerate feature only generates "candidate" commands which must be hand-tailored in any case, so is still a useful feature and is safe to use. Please report missing/broken features of autogenerate! This will be a great feature and will also improve SQLAlchemy's reflection services.

Support for non-ASCII table, column and constraint names is mostly nonexistent. This is also a straightforward feature add as SQLAlchemy itself supports unicode identifiers; Alembic itself will likely need fixes to logging, column identification by key, etc. for full support here.