--- /dev/null
+.. change::
+ :tags: usecase, schema
+ :tickets: 4894
+
+ Added DDL support for "computed columns"; these are DDL column
+ specifications for columns that have a server-computed value, either upon
+ SELECT (known as "virtual") or at the point of which they are INSERTed or
+ UPDATEd (known as "stored"). Support is established for Postgresql, MySQL,
+ Oracle SQL Server and Firebird. Thanks to Federico Caselli for lots of work
+ on this one.
+
+ .. seealso::
+
+ :ref:`computed_ddl`
+
:ref:`oracle_returning` - in the Oracle dialect documentation
+.. _computed_ddl:
+
+Computed (GENERATED ALWAYS AS) Columns
+--------------------------------------
+
+.. versionadded:: 1.3.11
+
+The :class:`.Computed` construct allows a :class:`.Column` to be declared in
+DDL as a "GENERATED ALWAYS AS" column, that is, one which has a value that is
+computed by the database server. The construct accepts a SQL expression
+typically declared textually using a string or the :func:`.text` construct, in
+a similar manner as that of :class:`.CheckConstraint`. The SQL expression is
+then interpreted by the database server in order to determine the value for the
+column within a row.
+
+Example::
+
+ from sqlalchemy import Table, Column, MetaData, Integer, Computed
+
+ metadata = MetaData()
+
+ square = Table(
+ "square",
+ metadata,
+ Column("id", Integer, primary_key=True),
+ Column("side", Integer),
+ Column("area", Integer, Computed("side * side")),
+ Column("perimeter", Integer, Computed("4 * side")),
+ )
+
+The DDL for the ``square`` table when run on a PostgreSQL 12 backend will look
+like::
+
+ CREATE TABLE square (
+ id SERIAL NOT NULL,
+ side INTEGER,
+ area INTEGER GENERATED ALWAYS AS (side * side) STORED,
+ perimeter INTEGER GENERATED ALWAYS AS (4 * side) STORED,
+ PRIMARY KEY (id)
+ )
+
+Whether the value is persisted upon INSERT and UPDATE, or if it is calculated
+on fetch, is an implementation detail of the database; the former is known as
+"stored" and the latter is known as "virtual". Some database implementations
+support both, but some only support one or the other. The optional
+:paramref:`.Computed.persisted` flag may be specified as ``True`` or ``False``
+to indicate if the "STORED" or "VIRTUAL" keyword should be rendered in DDL,
+however this will raise an error if the keyword is not supported by the target
+backend; leaving it unset will use a working default for the target backend.
+
+The :class:`.Computed` construct is a subclass of the :class:`.FetchedValue`
+object, and will set itself up as both the "server default" and "server
+onupdate" generator for the target :class:`.Column`, meaning it will be treated
+as a default generating column when INSERT and UPDATE statements are generated,
+as well as that it will be fetched as a generating column when using the ORM.
+This includes that it will be part of the RETURNING clause of the database
+for databases which support RETURNING and the generated values are to be
+eagerly fetched.
+
+.. note:: A :class:`.Column` that is defined with the :class:`.Computed`
+ construct may not store any value outside of that which the server applies
+ to it; SQLAlchemy's behavior when a value is passed for such a column
+ to be written in INSERT or UPDATE is currently that the value will be
+ ignored.
+
+"GENERATED ALWAYS AS" is currently known to be supported by:
+
+* MySQL version 5.7 and onwards
+
+* MariaDB 10.x series and onwards
+
+* PostgreSQL as of version 12
+
+* Oracle - with the caveat that RETURNING does not work correctly with UPDATE
+ (a warning will be emitted to this effect when the UPDATE..RETURNING that
+ includes a computed column is rendered)
+
+* Microsoft SQL Server
+
+* Firebird
+
+When :class:`.Computed` is used with an unsupported backend, if the target
+dialect does not support it, a :class:`.CompileError` is raised when attempting
+to render the construct. Otherwise, if the dialect supports it but the
+particular database server version in use does not, then a subclass of
+:class:`.DBAPIError`, usually :class:`.OperationalError`, is raised when the
+DDL is emitted to the database.
+
+.. seealso::
+
+ :class:`.Computed`
+
Default Objects API
-------------------
+.. autoclass:: Computed
+ :members:
+
+
.. autoclass:: ColumnDefault
from .schema import FetchedValue # noqa
from .schema import ForeignKey # noqa
from .schema import ForeignKeyConstraint # noqa
+from .schema import Computed # noqa
from .schema import Index # noqa
from .schema import MetaData # noqa
from .schema import PrimaryKeyConstraint # noqa
drop.element
)
+ def visit_computed_column(self, generated):
+ if generated.persisted is not None:
+ raise exc.CompileError(
+ "Firebird computed columns do not support a persistence "
+ "method setting; set the 'persisted' flag to None for "
+ "Firebird support."
+ )
+ return "GENERATED ALWAYS AS (%s)" % self.sql_compiler.process(
+ generated.sqltext, include_table=False, literal_binds=True
+ )
+
class FBIdentifierPreparer(sql.compiler.IdentifierPreparer):
"""Install Firebird specific reserved words."""
class MSDDLCompiler(compiler.DDLCompiler):
def get_column_specification(self, column, **kwargs):
- colspec = (
- self.preparer.format_column(column)
- + " "
- + self.dialect.type_compiler.process(
+ colspec = self.preparer.format_column(column)
+
+ # type is not accepted in a computed column
+ if column.computed is not None:
+ colspec += " " + self.process(column.computed)
+ else:
+ colspec += " " + self.dialect.type_compiler.process(
column.type, type_expression=column
)
- )
if column.nullable is not None:
if (
or column.autoincrement is True
):
colspec += " NOT NULL"
- else:
+ elif column.computed is None:
+ # don't specify "NULL" for computed columns
colspec += " NULL"
if column.table is None:
text += self.define_constraint_deferrability(constraint)
return text
+ def visit_computed_column(self, generated):
+ text = "AS (%s)" % self.sql_compiler.process(
+ generated.sqltext, include_table=False, literal_binds=True
+ )
+ # explicitly check for True|False since None means server default
+ if generated.persisted is True:
+ text += " PERSISTED"
+ return text
+
class MSIdentifierPreparer(compiler.IdentifierPreparer):
reserved_words = RESERVED_WORDS
),
]
+ if column.computed is not None:
+ colspec.append(self.process(column.computed))
+
is_timestamp = isinstance(
column.type._unwrapped_dialect_impl(self.dialect),
sqltypes.TIMESTAMP,
from itertools import groupby
import re
+from ... import Computed
from ... import exc
from ... import schema as sa_schema
from ... import sql
for i, column in enumerate(
expression._select_iterables(returning_cols)
):
+ if self.isupdate and isinstance(column.server_default, Computed):
+ util.warn(
+ "Computed columns don't work with Oracle UPDATE "
+ "statements that use RETURNING; the value of the column "
+ "*before* the UPDATE takes place is returned. It is "
+ "advised to not use RETURNING with an Oracle computed "
+ "column. Consider setting implicit_returning to False on "
+ "the Table object in order to avoid implicit RETURNING "
+ "clauses from being generated for this Table."
+ )
if column.type._has_column_expression:
col_expr = column.type.column_expression(column)
else:
return "".join(table_opts)
+ def visit_computed_column(self, generated):
+ text = "GENERATED ALWAYS AS (%s)" % self.sql_compiler.process(
+ generated.sqltext, include_table=False, literal_binds=True
+ )
+ if generated.persisted is True:
+ raise exc.CompileError(
+ "Oracle computed columns do not support 'stored' persistence; "
+ "set the 'persisted' flag to None or False for Oracle support."
+ )
+ elif generated.persisted is False:
+ text += " VIRTUAL"
+ return text
+
class OracleIdentifierPreparer(compiler.IdentifierPreparer):
if default is not None:
colspec += " DEFAULT " + default
+ if column.computed is not None:
+ colspec += " " + self.process(column.computed)
+
if not column.nullable:
colspec += " NOT NULL"
return colspec
return "".join(table_opts)
+ def visit_computed_column(self, generated):
+ if generated.persisted is False:
+ raise exc.CompileError(
+ "PostrgreSQL computed columns do not support 'virtual' "
+ "persistence; set the 'persisted' flag to None or True for "
+ "PostgreSQL support."
+ )
+
+ return "GENERATED ALWAYS AS (%s) STORED" % self.sql_compiler.process(
+ generated.sqltext, include_table=False, literal_binds=True
+ )
+
class PGTypeCompiler(compiler.GenericTypeCompiler):
def visit_TSVECTOR(self, type_, **kw):
class SQLiteDDLCompiler(compiler.DDLCompiler):
def get_column_specification(self, column, **kwargs):
+ if column.computed is not None:
+ raise exc.CompileError("SQLite does not support computed columns")
+
coltype = self.dialect.type_compiler.process(
column.type, type_expression=column
)
from .sql.schema import FetchedValue # noqa
from .sql.schema import ForeignKey # noqa
from .sql.schema import ForeignKeyConstraint # noqa
+from .sql.schema import Computed # noqa
from .sql.schema import Index # noqa
from .sql.schema import MetaData # noqa
from .sql.schema import PrimaryKeyConstraint # noqa
if default is not None:
colspec += " DEFAULT " + default
+ if column.computed is not None:
+ colspec += " " + self.process(column.computed)
+
if not column.nullable:
colspec += " NOT NULL"
return colspec
text += " MATCH %s" % constraint.match
return text
+ def visit_computed_column(self, generated):
+ text = "GENERATED ALWAYS AS (%s)" % self.sql_compiler.process(
+ generated.sqltext, include_table=False, literal_binds=True
+ )
+ if generated.persisted is True:
+ text += " STORED"
+ elif generated.persisted is False:
+ text += " VIRTUAL"
+ return text
+
class GenericTypeCompiler(TypeCompiler):
def visit_FLOAT(self, type_, **kw):
:class:`.SchemaItem` derived constructs which will be applied
as options to the column. These include instances of
:class:`.Constraint`, :class:`.ForeignKey`, :class:`.ColumnDefault`,
- and :class:`.Sequence`. In some cases an equivalent keyword
- argument is available such as ``server_default``, ``default``
- and ``unique``.
+ :class:`.Sequence`, :class:`.Computed`. In some cases an
+ equivalent keyword argument is available such as ``server_default``,
+ ``default`` and ``unique``.
:param autoincrement: Set up "auto increment" semantics for an integer
primary key column. The default value is the string ``"auto"``
self.constraints = set()
self.foreign_keys = set()
self.comment = kwargs.pop("comment", None)
+ self.computed = None
# check if this Column is proxying another column
if "_proxies" in kwargs:
c.copy(**kw) for c in self.constraints if not c._type_bound
] + [c.copy(**kw) for c in self.foreign_keys if not c.constraint]
+ server_default = self.server_default
+ server_onupdate = self.server_onupdate
+ if isinstance(server_default, Computed):
+ server_default = server_onupdate = None
+ args.append(self.server_default.copy(**kw))
+
type_ = self.type
if isinstance(type_, SchemaEventTarget):
type_ = type_.copy(**kw)
index=self.index,
autoincrement=self.autoincrement,
default=self.default,
- server_default=self.server_default,
+ server_default=server_default,
onupdate=self.onupdate,
- server_onupdate=self.server_onupdate,
+ server_onupdate=server_onupdate,
doc=self.doc,
comment=self.comment,
*args
_default_schema_map = _SchemaTranslateMap(None)
_schema_getter = _SchemaTranslateMap._schema_getter
+
+
+class Computed(FetchedValue, SchemaItem):
+ """Defines a generated column, i.e. "GENERATED ALWAYS AS" syntax.
+
+ The :class:`.Computed` construct is an inline construct added to the
+ argument list of a :class:`.Column` object::
+
+ from sqlalchemy import Computed
+
+ Table('square', meta,
+ Column('side', Float, nullable=False),
+ Column('area', Float, Computed('side * side'))
+ )
+
+ See the linked documentation below for complete details.
+
+ .. versionadded:: 1.3.11
+
+ .. seealso::
+
+ :ref:`computed_ddl`
+
+ """
+
+ __visit_name__ = "computed_column"
+
+ @_document_text_coercion(
+ "sqltext", ":class:`.Computed`", ":paramref:`.Computed.sqltext`"
+ )
+ def __init__(self, sqltext, persisted=None):
+ """Construct a GENERATED ALWAYS AS DDL construct to accompany a
+ :class:`.Column`.
+
+ :param sqltext:
+ A string containing the column generation expression, which will be
+ used verbatim, or a SQL expression construct, such as a :func:`.text`
+ object. If given as a string, the object is converted to a
+ :func:`.text` object.
+
+ :param persisted:
+ Optional, controls how this column should be persisted by the
+ database. Possible values are:
+
+ * None, the default, it will use the default persistence defined
+ by the database.
+ * True, will render ``GENERATED ALWAYS AS ... STORED``, or the
+ equivalent for the target database if supported
+ * False, will render ``GENERATED ALWAYS AS ... VIRTUAL``, or the
+ equivalent for the target database if supported.
+
+ Specifying ``True`` or ``False`` may raise an error when the DDL
+ is emitted to the target database if the databse does not support
+ that persistence option. Leaving this parameter at its default
+ of ``None`` is guaranteed to succeed for all databases that support
+ ``GENERATED ALWAYS AS``.
+
+ """
+ self.sqltext = coercions.expect(roles.DDLExpressionRole, sqltext)
+ self.persisted = persisted
+ self.column = None
+
+ def _set_parent(self, parent):
+ if not isinstance(
+ parent.server_default, (type(None), Computed)
+ ) or not isinstance(parent.server_onupdate, (type(None), Computed)):
+ raise exc.ArgumentError(
+ "A generated column cannot specify a server_default or a "
+ "server_onupdate argument"
+ )
+ self.column = parent
+ parent.computed = self
+ self.column.server_onupdate = self
+ self.column.server_default = self
+
+ def _as_for_update(self, for_update):
+ return self
+
+ def copy(self, target_table=None, **kw):
+ if target_table is not None:
+ sqltext = _copy_expression(self.sqltext, self.table, target_table)
+ else:
+ sqltext = self.sqltext
+ g = Computed(sqltext, persisted=self.persisted)
+
+ return self._schema_item_copy(g)
well as if it is included in the tokens used to create the id of the
parameter set.
- If omitted, the argment combinations are passed to parametrize as is. If
+ If omitted, the argument combinations are passed to parametrize as is. If
passed, each argument combination is turned into a pytest.param() object,
mapping the elements of the argument tuple to produce an id based on a
character value in the same position within the string template using the
r - the given argument should be passed and it should be added to the
id by calling repr()
- s- the given argument should be passed and it should be added to the
+ s - the given argument should be passed and it should be added to the
id by calling str()
+ a - (argument) the given argument should be passed and it should not
+ be used to generated the id
+
e.g.::
@testing.combinations(
return True
except ImportError:
return False
+
+ @property
+ def computed_columns(self):
+ return exclusions.closed()
from ..schema import Table
from ... import bindparam
from ... import case
+from ... import Computed
from ... import false
from ... import func
from ... import Integer
col = self.tables.some_table.c.data
self._test(col.contains("b%cd", autoescape=True, escape="#"), {3})
self._test(col.contains("b#cd", autoescape=True, escape="#"), {7})
+
+
+class ComputedColumnTest(fixtures.TablesTest):
+ __backend__ = True
+ __requires__ = ("computed_columns",)
+
+ @classmethod
+ def define_tables(cls, metadata):
+ Table(
+ "square",
+ metadata,
+ Column("id", Integer, primary_key=True),
+ Column("side", Integer),
+ Column("area", Integer, Computed("side * side")),
+ Column("perimeter", Integer, Computed("4 * side")),
+ )
+
+ @classmethod
+ def insert_data(cls):
+ with config.db.begin() as conn:
+ conn.execute(
+ cls.tables.square.insert(),
+ [{"id": 1, "side": 10}, {"id": 10, "side": 42}],
+ )
+
+ def test_select_all(self):
+ with config.db.connect() as conn:
+ res = conn.execute(
+ select([text("*")])
+ .select_from(self.tables.square)
+ .order_by(self.tables.square.c.id)
+ ).fetchall()
+ eq_(res, [(1, 10, 100, 40), (10, 42, 1764, 168)])
+
+ def test_select_columns(self):
+ with config.db.connect() as conn:
+ res = conn.execute(
+ select(
+ [self.tables.square.c.area, self.tables.square.c.perimeter]
+ )
+ .select_from(self.tables.square)
+ .order_by(self.tables.square.c.id)
+ ).fetchall()
+ eq_(res, [(100, 40), (1764, 168)])
# -*- encoding: utf-8
from sqlalchemy import Column
+from sqlalchemy import Computed
from sqlalchemy import delete
from sqlalchemy import extract
from sqlalchemy import func
"SELECT TRY_CAST (t1.id AS INTEGER) AS id FROM t1",
)
+ @testing.combinations(
+ ("no_persisted", "", "ignore"),
+ ("persisted_none", "", None),
+ ("persisted_true", " PERSISTED", True),
+ ("persisted_false", "", False),
+ id_="iaa",
+ )
+ def test_column_computed(self, text, persisted):
+ m = MetaData()
+ kwargs = {"persisted": persisted} if persisted != "ignore" else {}
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", **kwargs)),
+ )
+ self.assert_compile(
+ schema.CreateTable(t),
+ "CREATE TABLE t (x INTEGER NULL, y AS (x + 2)%s)" % text,
+ )
+
class SchemaTest(fixtures.TestBase):
def setup(self):
from sqlalchemy import CheckConstraint
from sqlalchemy import CLOB
from sqlalchemy import Column
+from sqlalchemy import Computed
from sqlalchemy import DATE
from sqlalchemy import Date
from sqlalchemy import DATETIME
)
self.assert_compile(sql.delete(a1), "DELETE FROM t1 AS a1")
+ @testing.combinations(
+ ("no_persisted", "", "ignore"),
+ ("persisted_none", "", None),
+ ("persisted_true", " STORED", True),
+ ("persisted_false", " VIRTUAL", False),
+ id_="iaa",
+ )
+ def test_column_computed(self, text, persisted):
+ m = MetaData()
+ kwargs = {"persisted": persisted} if persisted != "ignore" else {}
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", **kwargs)),
+ )
+ self.assert_compile(
+ schema.CreateTable(t),
+ "CREATE TABLE t (x INTEGER, y INTEGER GENERATED "
+ "ALWAYS AS (x + 2)%s)" % text,
+ )
+
class SQLTest(fixtures.TestBase, AssertsCompiledSQL):
# coding: utf-8
from sqlalchemy import and_
from sqlalchemy import bindparam
+from sqlalchemy import Computed
+from sqlalchemy import exc
from sqlalchemy import except_
from sqlalchemy import ForeignKey
from sqlalchemy import func
from sqlalchemy.sql import column
from sqlalchemy.sql import quoted_name
from sqlalchemy.sql import table
+from sqlalchemy.testing import assert_raises_message
from sqlalchemy.testing import AssertsCompiledSQL
from sqlalchemy.testing import eq_
from sqlalchemy.testing import fixtures
"t1.c2, t1.c3 INTO :ret_0, :ret_1",
)
+ def test_returning_insert_computed(self):
+ m = MetaData()
+ t1 = Table(
+ "t1",
+ m,
+ Column("id", Integer, primary_key=True),
+ Column("foo", Integer),
+ Column("bar", Integer, Computed("foo + 42")),
+ )
+
+ self.assert_compile(
+ t1.insert().values(id=1, foo=5).returning(t1.c.bar),
+ "INSERT INTO t1 (id, foo) VALUES (:id, :foo) "
+ "RETURNING t1.bar INTO :ret_0",
+ )
+
+ def test_returning_update_computed_warning(self):
+ m = MetaData()
+ t1 = Table(
+ "t1",
+ m,
+ Column("id", Integer, primary_key=True),
+ Column("foo", Integer),
+ Column("bar", Integer, Computed("foo + 42")),
+ )
+
+ with testing.expect_warnings(
+ "Computed columns don't work with Oracle UPDATE"
+ ):
+ self.assert_compile(
+ t1.update().values(id=1, foo=5).returning(t1.c.bar),
+ "UPDATE t1 SET id=:id, foo=:foo RETURNING t1.bar INTO :ret_0",
+ )
+
def test_compound(self):
t1 = table("t1", column("c1"), column("c2"), column("c3"))
t2 = table("t2", column("c1"), column("c2"), column("c3"))
"CREATE BITMAP INDEX idx3 ON testtbl (data)",
)
+ @testing.combinations(
+ ("no_persisted", "", "ignore"),
+ ("persisted_none", "", None),
+ ("persisted_false", " VIRTUAL", False),
+ id_="iaa",
+ )
+ def test_column_computed(self, text, persisted):
+ m = MetaData()
+ kwargs = {"persisted": persisted} if persisted != "ignore" else {}
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", **kwargs)),
+ )
+ self.assert_compile(
+ schema.CreateTable(t),
+ "CREATE TABLE t (x INTEGER, y INTEGER GENERATED "
+ "ALWAYS AS (x + 2)%s)" % text,
+ )
+
+ def test_column_computed_persisted_true(self):
+ m = MetaData()
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", persisted=True)),
+ )
+ assert_raises_message(
+ exc.CompileError,
+ r".*Oracle computed columns do not support 'stored' ",
+ schema.CreateTable(t).compile,
+ dialect=oracle.dialect(),
+ )
+
class SequenceTest(fixtures.TestBase, AssertsCompiledSQL):
def test_basic(self):
import re
from sqlalchemy import bindparam
+from sqlalchemy import Computed
from sqlalchemy import create_engine
from sqlalchemy import exc
from sqlalchemy import Float
)
+class ComputedReturningTest(fixtures.TablesTest):
+ __only_on__ = "oracle"
+ __backend__ = True
+
+ @classmethod
+ def define_tables(cls, metadata):
+ Table(
+ "test",
+ metadata,
+ Column("id", Integer, primary_key=True),
+ Column("foo", Integer),
+ Column("bar", Integer, Computed("foo + 42")),
+ )
+
+ Table(
+ "test_no_returning",
+ metadata,
+ Column("id", Integer, primary_key=True),
+ Column("foo", Integer),
+ Column("bar", Integer, Computed("foo + 42")),
+ implicit_returning=False,
+ )
+
+ def test_computed_insert(self):
+ test = self.tables.test
+ with testing.db.connect() as conn:
+ result = conn.execute(
+ test.insert().return_defaults(), {"id": 1, "foo": 5}
+ )
+
+ eq_(result.returned_defaults, (47,))
+
+ eq_(conn.scalar(select([test.c.bar])), 47)
+
+ def test_computed_update_warning(self):
+ test = self.tables.test
+ with testing.db.connect() as conn:
+ conn.execute(test.insert(), {"id": 1, "foo": 5})
+
+ with testing.expect_warnings(
+ "Computed columns don't work with Oracle UPDATE"
+ ):
+ result = conn.execute(
+ test.update().values(foo=10).return_defaults()
+ )
+
+ # returns the *old* value
+ eq_(result.returned_defaults, (47,))
+
+ eq_(conn.scalar(select([test.c.bar])), 52)
+
+ def test_computed_update_no_warning(self):
+ test = self.tables.test_no_returning
+ with testing.db.connect() as conn:
+ conn.execute(test.insert(), {"id": 1, "foo": 5})
+
+ result = conn.execute(
+ test.update().values(foo=10).return_defaults()
+ )
+
+ # no returning
+ eq_(result.returned_defaults, None)
+
+ eq_(conn.scalar(select([test.c.bar])), 52)
+
+
class OutParamTest(fixtures.TestBase, AssertsExecutionResults):
__only_on__ = "oracle+cx_oracle"
__backend__ = True
from sqlalchemy import and_
from sqlalchemy import cast
from sqlalchemy import Column
+from sqlalchemy import Computed
from sqlalchemy import delete
from sqlalchemy import Enum
from sqlalchemy import exc
q, "DELETE FROM t1 AS a1 USING t2 WHERE a1.c1 = t2.c1"
)
+ @testing.combinations(
+ ("no_persisted", " STORED", "ignore"),
+ ("persisted_none", " STORED", None),
+ ("persisted_true", " STORED", True),
+ id_="iaa",
+ )
+ def test_column_computed(self, text, persisted):
+ m = MetaData()
+ kwargs = {"persisted": persisted} if persisted != "ignore" else {}
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", **kwargs)),
+ )
+ self.assert_compile(
+ schema.CreateTable(t),
+ "CREATE TABLE t (x INTEGER, y INTEGER GENERATED "
+ "ALWAYS AS (x + 2)%s)" % text,
+ )
+
+ def test_column_computed_persisted_false(self):
+ m = MetaData()
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", persisted=False)),
+ )
+ assert_raises_message(
+ exc.CompileError,
+ "PostrgreSQL computed columns do not support 'virtual'",
+ schema.CreateTable(t).compile,
+ dialect=postgresql.dialect(),
+ )
+
class InsertOnConflictTest(fixtures.TestBase, AssertsCompiledSQL):
__dialect__ = postgresql.dialect()
from sqlalchemy import Column
+from sqlalchemy import Computed
from sqlalchemy import exc
from sqlalchemy import Float
from sqlalchemy import func
self.assert_compile(column("_somecol"), '"_somecol"')
self.assert_compile(column("$somecol"), '"$somecol"')
+ @testing.combinations(
+ ("no_persisted", "ignore"), ("persisted_none", None), id_="ia"
+ )
+ def test_column_computed(self, persisted):
+ m = MetaData()
+ kwargs = {"persisted": persisted} if persisted != "ignore" else {}
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", **kwargs)),
+ )
+ self.assert_compile(
+ schema.CreateTable(t),
+ "CREATE TABLE t (x INTEGER, y INTEGER GENERATED "
+ "ALWAYS AS (x + 2))",
+ )
+
+ @testing.combinations(
+ ("persisted_true", True), ("persisted_false", False), id_="ia"
+ )
+ def test_column_computed_raises(self, persisted):
+ m = MetaData()
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", persisted=persisted)),
+ )
+ assert_raises_message(
+ exc.CompileError,
+ "Firebird computed columns do not support a persistence method",
+ schema.CreateTable(t).compile,
+ dialect=firebird.dialect(),
+ )
+
class TypesTest(fixtures.TestBase):
__only_on__ = "firebird"
from sqlalchemy import CheckConstraint
from sqlalchemy import Column
from sqlalchemy import column
+from sqlalchemy import Computed
from sqlalchemy import create_engine
from sqlalchemy import DefaultClause
from sqlalchemy import event
url = make_url(url)
eq_(d.create_connect_args(url), expected)
+ @testing.combinations(
+ ("no_persisted", "ignore"),
+ ("persisted_none", None),
+ ("persisted_true", True),
+ ("persisted_false", False),
+ id_="ia",
+ )
+ def test_column_computed(self, persisted):
+ m = MetaData()
+ kwargs = {"persisted": persisted} if persisted != "ignore" else {}
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", **kwargs)),
+ )
+ assert_raises_message(
+ exc.CompileError,
+ "SQLite does not support computed columns",
+ schema.CreateTable(t).compile,
+ dialect=sqlite.dialect(),
+ )
+
class AttachedDBTest(fixtures.TestBase):
__only_on__ = "sqlite"
import sqlalchemy as sa
+from sqlalchemy import Computed
from sqlalchemy import event
from sqlalchemy import Integer
from sqlalchemy import String
+from sqlalchemy import testing
from sqlalchemy.orm import create_session
from sqlalchemy.orm import mapper
+from sqlalchemy.orm import Session
from sqlalchemy.testing import eq_
from sqlalchemy.testing import fixtures
+from sqlalchemy.testing.assertsql import assert_engine
+from sqlalchemy.testing.assertsql import CompiledSQL
from sqlalchemy.testing.schema import Column
from sqlalchemy.testing.schema import Table
sess.add(f1)
sess.flush()
eq_(dt.select().execute().fetchall(), [(1, "hello")])
+
+
+class ComputedDefaultsOnUpdateTest(fixtures.MappedTest):
+ """test that computed columns are recognized as server
+ oninsert/onupdate defaults."""
+
+ __backend__ = True
+ __requires__ = ("computed_columns",)
+
+ @classmethod
+ def define_tables(cls, metadata):
+ Table(
+ "test",
+ metadata,
+ Column("id", Integer, primary_key=True),
+ Column("foo", Integer),
+ Column("bar", Integer, Computed("foo + 42")),
+ )
+
+ @classmethod
+ def setup_classes(cls):
+ class Thing(cls.Basic):
+ pass
+
+ class ThingNoEager(cls.Basic):
+ pass
+
+ @classmethod
+ def setup_mappers(cls):
+ Thing = cls.classes.Thing
+
+ mapper(Thing, cls.tables.test, eager_defaults=True)
+
+ ThingNoEager = cls.classes.ThingNoEager
+ mapper(ThingNoEager, cls.tables.test, eager_defaults=False)
+
+ @testing.combinations(("eager", True), ("noneager", False), id_="ia")
+ def test_insert_computed(self, eager):
+ if eager:
+ Thing = self.classes.Thing
+ else:
+ Thing = self.classes.ThingNoEager
+
+ s = Session()
+
+ t1, t2 = (Thing(id=1, foo=5), Thing(id=2, foo=10))
+
+ s.add_all([t1, t2])
+
+ with assert_engine(testing.db) as asserter:
+ s.flush()
+ eq_(t1.bar, 5 + 42)
+ eq_(t2.bar, 10 + 42)
+
+ if eager and testing.db.dialect.implicit_returning:
+ asserter.assert_(
+ CompiledSQL(
+ "INSERT INTO test (id, foo) VALUES (%(id)s, %(foo)s) "
+ "RETURNING test.bar",
+ [{"foo": 5, "id": 1}],
+ dialect="postgresql",
+ ),
+ CompiledSQL(
+ "INSERT INTO test (id, foo) VALUES (%(id)s, %(foo)s) "
+ "RETURNING test.bar",
+ [{"foo": 10, "id": 2}],
+ dialect="postgresql",
+ ),
+ )
+ else:
+ asserter.assert_(
+ CompiledSQL(
+ "INSERT INTO test (id, foo) VALUES (:id, :foo)",
+ [{"foo": 5, "id": 1}, {"foo": 10, "id": 2}],
+ ),
+ CompiledSQL(
+ "SELECT test.bar AS test_bar FROM test "
+ "WHERE test.id = :param_1",
+ [{"param_1": 1}],
+ ),
+ CompiledSQL(
+ "SELECT test.bar AS test_bar FROM test "
+ "WHERE test.id = :param_1",
+ [{"param_1": 2}],
+ ),
+ )
+
+ @testing.requires.computed_columns_on_update_returning
+ def test_update_computed_eager(self):
+ self._test_update_computed(True)
+
+ def test_update_computed_noneager(self):
+ self._test_update_computed(False)
+
+ def _test_update_computed(self, eager):
+ if eager:
+ Thing = self.classes.Thing
+ else:
+ Thing = self.classes.ThingNoEager
+
+ s = Session()
+
+ t1, t2 = (Thing(id=1, foo=1), Thing(id=2, foo=2))
+
+ s.add_all([t1, t2])
+ s.flush()
+
+ t1.foo = 5
+ t2.foo = 6
+
+ with assert_engine(testing.db) as asserter:
+ s.flush()
+ eq_(t1.bar, 5 + 42)
+ eq_(t2.bar, 6 + 42)
+
+ if eager and testing.db.dialect.implicit_returning:
+ asserter.assert_(
+ CompiledSQL(
+ "UPDATE test SET foo=%(foo)s "
+ "WHERE test.id = %(test_id)s "
+ "RETURNING test.bar",
+ [{"foo": 5, "test_id": 1}],
+ dialect="postgresql",
+ ),
+ CompiledSQL(
+ "UPDATE test SET foo=%(foo)s "
+ "WHERE test.id = %(test_id)s "
+ "RETURNING test.bar",
+ [{"foo": 6, "test_id": 2}],
+ dialect="postgresql",
+ ),
+ )
+ elif eager:
+ asserter.assert_(
+ CompiledSQL(
+ "UPDATE test SET foo=:foo WHERE test.id = :test_id",
+ [{"foo": 5, "test_id": 1}],
+ ),
+ CompiledSQL(
+ "UPDATE test SET foo=:foo WHERE test.id = :test_id",
+ [{"foo": 6, "test_id": 2}],
+ ),
+ CompiledSQL(
+ "SELECT test.bar AS test_bar FROM test "
+ "WHERE test.id = :param_1",
+ [{"param_1": 1}],
+ ),
+ CompiledSQL(
+ "SELECT test.bar AS test_bar FROM test "
+ "WHERE test.id = :param_1",
+ [{"param_1": 2}],
+ ),
+ )
+ else:
+ asserter.assert_(
+ CompiledSQL(
+ "UPDATE test SET foo=:foo WHERE test.id = :test_id",
+ [{"foo": 5, "test_id": 1}, {"foo": 6, "test_id": 2}],
+ ),
+ CompiledSQL(
+ "SELECT test.bar AS test_bar FROM test "
+ "WHERE test.id = :param_1",
+ [{"param_1": 1}],
+ ),
+ CompiledSQL(
+ "SELECT test.bar AS test_bar FROM test "
+ "WHERE test.id = :param_1",
+ [{"param_1": 2}],
+ ),
+ )
def sql_expressions_inserted_as_primary_key(self):
return only_if([self.returning, self.sqlite])
+ @property
+ def computed_columns_on_update_returning(self):
+ return self.computed_columns + skip_if("oracle")
+
@property
def correlated_outer_joins(self):
"""Target must support an outer join to a subquery which
@property
def nullsordering(self):
"""Target backends that support nulls ordering."""
- return fails_on_everything_except("postgresql", "oracle", "firebird",
- "sqlite >= 3.30.0")
+ return fails_on_everything_except(
+ "postgresql", "oracle", "firebird", "sqlite >= 3.30.0"
+ )
@property
def reflects_pk_names(self):
lambda config: against(config, "oracle+cx_oracle")
and config.db.dialect.cx_oracle_ver < (6,)
)
+
+ @property
+ def computed_columns(self):
+ return skip_if(["postgresql < 12", "sqlite", "mysql < 5.7"])
--- /dev/null
+# coding: utf-8
+from sqlalchemy import Column
+from sqlalchemy import Computed
+from sqlalchemy import Integer
+from sqlalchemy import MetaData
+from sqlalchemy import Table
+from sqlalchemy.exc import ArgumentError
+from sqlalchemy.schema import CreateTable
+from sqlalchemy.testing import assert_raises_message
+from sqlalchemy.testing import AssertsCompiledSQL
+from sqlalchemy.testing import combinations
+from sqlalchemy.testing import fixtures
+from sqlalchemy.testing import is_
+from sqlalchemy.testing import is_not_
+
+
+class DDLComputedTest(fixtures.TestBase, AssertsCompiledSQL):
+ __dialect__ = "default"
+
+ @combinations(
+ ("no_persisted", "", "ignore"),
+ ("persisted_none", "", None),
+ ("persisted_true", " STORED", True),
+ ("persisted_false", " VIRTUAL", False),
+ id_="iaa",
+ )
+ def test_column_computed(self, text, persisted):
+ m = MetaData()
+ kwargs = {"persisted": persisted} if persisted != "ignore" else {}
+ t = Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2", **kwargs)),
+ )
+ self.assert_compile(
+ CreateTable(t),
+ "CREATE TABLE t (x INTEGER, y INTEGER GENERATED "
+ "ALWAYS AS (x + 2)%s)" % text,
+ )
+
+ def test_server_default_onupdate(self):
+ text = (
+ "A generated column cannot specify a server_default or a "
+ "server_onupdate argument"
+ )
+
+ def fn(**kwargs):
+ m = MetaData()
+ Table(
+ "t",
+ m,
+ Column("x", Integer),
+ Column("y", Integer, Computed("x + 2"), **kwargs),
+ )
+
+ assert_raises_message(ArgumentError, text, fn, server_default="42")
+ assert_raises_message(ArgumentError, text, fn, server_onupdate="42")
+
+ def test_tometadata(self):
+ comp1 = Computed("x + 2")
+ m = MetaData()
+ t = Table("t", m, Column("x", Integer), Column("y", Integer, comp1))
+ is_(comp1.column, t.c.y)
+ is_(t.c.y.server_onupdate, comp1)
+ is_(t.c.y.server_default, comp1)
+
+ m2 = MetaData()
+ t2 = t.tometadata(m2)
+ comp2 = t2.c.y.server_default
+
+ is_not_(comp1, comp2)
+
+ is_(comp1.column, t.c.y)
+ is_(t.c.y.server_onupdate, comp1)
+ is_(t.c.y.server_default, comp1)
+
+ is_(comp2.column, t2.c.y)
+ is_(t2.c.y.server_onupdate, comp2)
+ is_(t2.c.y.server_default, comp2)
class ToMetaDataTest(fixtures.TestBase, ComparesTables):
@testing.requires.check_constraints
def test_copy(self):
+ # TODO: modernize this test
+
from sqlalchemy.testing.schema import Table
meta = MetaData()
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
