sqlalchemy/test/ext/test_compiler.py

from sqlalchemy import *
from sqlalchemy.types import TypeEngine
from sqlalchemy.sql.expression import ClauseElement, ColumnClause,\
                                    FunctionElement, Select, \
                                    BindParameter, ColumnElement

from sqlalchemy.schema import DDLElement, CreateColumn, CreateTable
from sqlalchemy.ext.compiler import compiles, deregister
from sqlalchemy import exc
from sqlalchemy.testing import eq_
from sqlalchemy.sql import table, column
from sqlalchemy.testing import assert_raises_message
from sqlalchemy.testing import fixtures, AssertsCompiledSQL


class UserDefinedTest(fixtures.TestBase, AssertsCompiledSQL):
    __dialect__ = 'default'

    def test_column(self):

        class MyThingy(ColumnClause):
            def __init__(self, arg=None):
                super(MyThingy, self).__init__(arg or 'MYTHINGY!')

        @compiles(MyThingy)
        def visit_thingy(thingy, compiler, **kw):
            return ">>%s<<" % thingy.name

        self.assert_compile(
            select([column('foo'), MyThingy()]),
            "SELECT foo, >>MYTHINGY!<<"
        )

        self.assert_compile(
            select([MyThingy('x'), MyThingy('y')]).where(MyThingy() == 5),
            "SELECT >>x<<, >>y<< WHERE >>MYTHINGY!<< = :MYTHINGY!_1"
        )

    def test_create_column_skip(self):
        @compiles(CreateColumn)
        def skip_xmin(element, compiler, **kw):
            if element.element.name == 'xmin':
                return None
            else:
                return compiler.visit_create_column(element, **kw)

        t = Table('t', MetaData(), Column('a', Integer),
                  Column('xmin', Integer),
                  Column('c', Integer))

        self.assert_compile(
            CreateTable(t),
            "CREATE TABLE t (a INTEGER, c INTEGER)"
        )

    def test_types(self):
        class MyType(TypeEngine):
            pass

        @compiles(MyType, 'sqlite')
        def visit_type(type, compiler, **kw):
            return "SQLITE_FOO"

        @compiles(MyType, 'postgresql')
        def visit_type(type, compiler, **kw):
            return "POSTGRES_FOO"

        from sqlalchemy.dialects.sqlite import base as sqlite
        from sqlalchemy.dialects.postgresql import base as postgresql

        self.assert_compile(
            MyType(),
            "SQLITE_FOO",
            dialect=sqlite.dialect()
        )

        self.assert_compile(
            MyType(),
            "POSTGRES_FOO",
            dialect=postgresql.dialect()
        )

    def test_stateful(self):
        class MyThingy(ColumnClause):
            def __init__(self):
                super(MyThingy, self).__init__('MYTHINGY!')

        @compiles(MyThingy)
        def visit_thingy(thingy, compiler, **kw):
            if not hasattr(compiler, 'counter'):
                compiler.counter = 0
            compiler.counter += 1
            return str(compiler.counter)

        self.assert_compile(
            select([column('foo'), MyThingy()]).order_by(desc(MyThingy())),
            "SELECT foo, 1 ORDER BY 2 DESC"
        )

        self.assert_compile(
            select([MyThingy(), MyThingy()]).where(MyThingy() == 5),
            "SELECT 1, 2 WHERE 3 = :MYTHINGY!_1"
        )

    def test_callout_to_compiler(self):
        class InsertFromSelect(ClauseElement):
            def __init__(self, table, select):
                self.table = table
                self.select = select

        @compiles(InsertFromSelect)
        def visit_insert_from_select(element, compiler, **kw):
            return "INSERT INTO %s (%s)" % (
                compiler.process(element.table, asfrom=True),
                compiler.process(element.select)
            )

        t1 = table("mytable", column('x'), column('y'), column('z'))
        self.assert_compile(
            InsertFromSelect(
                t1,
                select([t1]).where(t1.c.x > 5)
            ),
            "INSERT INTO mytable (SELECT mytable.x, mytable.y, mytable.z "
            "FROM mytable WHERE mytable.x > :x_1)"
        )

    def test_no_default_but_has_a_visit(self):
        class MyThingy(ColumnClause):
            pass

        @compiles(MyThingy, 'postgresql')
        def visit_thingy(thingy, compiler, **kw):
            return "mythingy"

        eq_(str(MyThingy('x')), "x")

    def test_no_default_has_no_visit(self):
        class MyThingy(TypeEngine):
            pass

        @compiles(MyThingy, 'postgresql')
        def visit_thingy(thingy, compiler, **kw):
            return "mythingy"

        assert_raises_message(
            exc.CompileError,
            "<class 'test.ext.test_compiler..*MyThingy'> "
            "construct has no default compilation handler.",
            str, MyThingy()
        )

    def test_no_default_message(self):
        class MyThingy(ClauseElement):
            pass

        @compiles(MyThingy, 'postgresql')
        def visit_thingy(thingy, compiler, **kw):
            return "mythingy"

        assert_raises_message(
            exc.CompileError,
            "<class 'test.ext.test_compiler..*MyThingy'> "
            "construct has no default compilation handler.",
            str, MyThingy()
        )

    def test_default_subclass(self):
        from sqlalchemy.types import ARRAY

        class MyArray(ARRAY):
            pass

        @compiles(MyArray, "sqlite")
        def sl_array(elem, compiler, **kw):
            return "array"

        self.assert_compile(
            MyArray(Integer),
            "INTEGER[]",
            dialect="postgresql"
        )

    def test_annotations(self):
        """test that annotated clause constructs use the
        decorated class' compiler.

        """

        t1 = table('t1', column('c1'), column('c2'))

        dispatch = Select._compiler_dispatch
        try:
            @compiles(Select)
            def compile(element, compiler, **kw):
                return "OVERRIDE"

            s1 = select([t1])
            self.assert_compile(
                s1, "OVERRIDE"
            )
            self.assert_compile(
                s1._annotate({}),
                "OVERRIDE"
            )
        finally:
            Select._compiler_dispatch = dispatch
            if hasattr(Select, '_compiler_dispatcher'):
                del Select._compiler_dispatcher

    def test_dialect_specific(self):
        class AddThingy(DDLElement):
            __visit_name__ = 'add_thingy'

        class DropThingy(DDLElement):
            __visit_name__ = 'drop_thingy'

        @compiles(AddThingy, 'sqlite')
        def visit_add_thingy(thingy, compiler, **kw):
            return "ADD SPECIAL SL THINGY"

        @compiles(AddThingy)
        def visit_add_thingy(thingy, compiler, **kw):
            return "ADD THINGY"

        @compiles(DropThingy)
        def visit_drop_thingy(thingy, compiler, **kw):
            return "DROP THINGY"

        self.assert_compile(AddThingy(), "ADD THINGY")

        self.assert_compile(DropThingy(), "DROP THINGY")

        from sqlalchemy.dialects.sqlite import base
        self.assert_compile(AddThingy(),
                            "ADD SPECIAL SL THINGY",
                            dialect=base.dialect())

        self.assert_compile(DropThingy(),
                            "DROP THINGY",
                            dialect=base.dialect())

        @compiles(DropThingy, 'sqlite')
        def visit_drop_thingy(thingy, compiler, **kw):
            return "DROP SPECIAL SL THINGY"

        self.assert_compile(DropThingy(),
                            "DROP SPECIAL SL THINGY",
                            dialect=base.dialect())

        self.assert_compile(DropThingy(), "DROP THINGY")

    def test_functions(self):
        from sqlalchemy.dialects import postgresql

        class MyUtcFunction(FunctionElement):
            pass

        @compiles(MyUtcFunction)
        def visit_myfunc(element, compiler, **kw):
            return "utcnow()"

        @compiles(MyUtcFunction, 'postgresql')
        def visit_myfunc(element, compiler, **kw):
            return "timezone('utc', current_timestamp)"

        self.assert_compile(
            MyUtcFunction(),
            "utcnow()",
            use_default_dialect=True
        )
        self.assert_compile(
            MyUtcFunction(),
            "timezone('utc', current_timestamp)",
            dialect=postgresql.dialect()
        )

    def test_function_calls_base(self):
        from sqlalchemy.dialects import mssql

        class greatest(FunctionElement):
            type = Numeric()
            name = 'greatest'

        @compiles(greatest)
        def default_greatest(element, compiler, **kw):
            return compiler.visit_function(element)

        @compiles(greatest, 'mssql')
        def case_greatest(element, compiler, **kw):
            arg1, arg2 = list(element.clauses)
            return "CASE WHEN %s > %s THEN %s ELSE %s END" % (
                compiler.process(arg1),
                compiler.process(arg2),
                compiler.process(arg1),
                compiler.process(arg2),
            )

        self.assert_compile(
            greatest('a', 'b'),
            'greatest(:greatest_1, :greatest_2)',
            use_default_dialect=True
        )
        self.assert_compile(
            greatest('a', 'b'),
            "CASE WHEN :greatest_1 > :greatest_2 "
            "THEN :greatest_1 ELSE :greatest_2 END",
            dialect=mssql.dialect()
        )

    def test_subclasses_one(self):
        class Base(FunctionElement):
            name = 'base'

        class Sub1(Base):
            name = 'sub1'

        class Sub2(Base):
            name = 'sub2'

        @compiles(Base)
        def visit_base(element, compiler, **kw):
            return element.name

        @compiles(Sub1)
        def visit_base(element, compiler, **kw):
            return "FOO" + element.name

        self.assert_compile(
            select([Sub1(), Sub2()]),
            'SELECT FOOsub1, sub2',
            use_default_dialect=True
        )

    def test_subclasses_two(self):
        class Base(FunctionElement):
            name = 'base'

        class Sub1(Base):
            name = 'sub1'

        @compiles(Base)
        def visit_base(element, compiler, **kw):
            return element.name

        class Sub2(Base):
            name = 'sub2'

        class SubSub1(Sub1):
            name = 'subsub1'

        self.assert_compile(
            select([Sub1(), Sub2(), SubSub1()]),
            'SELECT sub1, sub2, subsub1',
            use_default_dialect=True
        )

        @compiles(Sub1)
        def visit_base(element, compiler, **kw):
            return "FOO" + element.name

        self.assert_compile(
            select([Sub1(), Sub2(), SubSub1()]),
            'SELECT FOOsub1, sub2, FOOsubsub1',
            use_default_dialect=True
        )


class DefaultOnExistingTest(fixtures.TestBase, AssertsCompiledSQL):
    """Test replacement of default compilation on existing constructs."""
    __dialect__ = 'default'

    def teardown(self):
        for cls in (Select, BindParameter):
            deregister(cls)

    def test_select(self):
        t1 = table('t1', column('c1'), column('c2'))

        @compiles(Select, 'sqlite')
        def compile(element, compiler, **kw):
            return "OVERRIDE"

        s1 = select([t1])
        self.assert_compile(
            s1, "SELECT t1.c1, t1.c2 FROM t1",
        )

        from sqlalchemy.dialects.sqlite import base as sqlite
        self.assert_compile(
            s1, "OVERRIDE",
            dialect=sqlite.dialect()
        )

    def test_binds_in_select(self):
        t = table('t',
                  column('a'),
                  column('b'),
                  column('c'))

        @compiles(BindParameter)
        def gen_bind(element, compiler, **kw):
            return "BIND(%s)" % compiler.visit_bindparam(element, **kw)

        self.assert_compile(
            t.select().where(t.c.c == 5),
            "SELECT t.a, t.b, t.c FROM t WHERE t.c = BIND(:c_1)",
            use_default_dialect=True
        )

    def test_binds_in_dml(self):
        t = table('t',
                  column('a'),
                  column('b'),
                  column('c'))

        @compiles(BindParameter)
        def gen_bind(element, compiler, **kw):
            return "BIND(%s)" % compiler.visit_bindparam(element, **kw)

        self.assert_compile(
            t.insert(),
            "INSERT INTO t (a, b) VALUES (BIND(:a), BIND(:b))",
            {'a': 1, 'b': 2},
            use_default_dialect=True
        )