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"""
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Oracle database specific implementations of changeset classes.
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"""
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import sqlalchemy as sa
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from sqlalchemy.databases import oracle as sa_base
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from migrate import exceptions
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from migrate.changeset import ansisql, SQLA_06
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if not SQLA_06:
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OracleSchemaGenerator = sa_base.OracleSchemaGenerator
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else:
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OracleSchemaGenerator = sa_base.OracleDDLCompiler
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class OracleColumnGenerator(OracleSchemaGenerator, ansisql.ANSIColumnGenerator):
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pass
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class OracleColumnDropper(ansisql.ANSIColumnDropper):
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pass
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class OracleSchemaChanger(OracleSchemaGenerator, ansisql.ANSISchemaChanger):
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def get_column_specification(self, column, **kwargs):
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# Ignore the NOT NULL generated
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override_nullable = kwargs.pop('override_nullable', None)
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if override_nullable:
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orig = column.nullable
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column.nullable = True
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ret = super(OracleSchemaChanger, self).get_column_specification(
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column, **kwargs)
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if override_nullable:
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column.nullable = orig
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return ret
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def visit_column(self, delta):
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keys = delta.keys()
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if 'name' in keys:
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self._run_subvisit(delta,
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self._visit_column_name,
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start_alter=False)
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if len(set(('type', 'nullable', 'server_default')).intersection(keys)):
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self._run_subvisit(delta,
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self._visit_column_change,
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start_alter=False)
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def _visit_column_change(self, table, column, delta):
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# Oracle cannot drop a default once created, but it can set it
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# to null. We'll do that if default=None
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# http://forums.oracle.com/forums/message.jspa?messageID=1273234#1273234
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dropdefault_hack = (column.server_default is None \
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and 'server_default' in delta.keys())
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# Oracle apparently doesn't like it when we say "not null" if
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# the column's already not null. Fudge it, so we don't need a
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# new function
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notnull_hack = ((not column.nullable) \
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and ('nullable' not in delta.keys()))
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# We need to specify NULL if we're removing a NOT NULL
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# constraint
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null_hack = (column.nullable and ('nullable' in delta.keys()))
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if dropdefault_hack:
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column.server_default = sa.PassiveDefault(sa.sql.null())
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if notnull_hack:
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column.nullable = True
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colspec = self.get_column_specification(column,
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override_nullable=null_hack)
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if null_hack:
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colspec += ' NULL'
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if notnull_hack:
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column.nullable = False
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if dropdefault_hack:
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column.server_default = None
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self.start_alter_table(table)
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self.append("MODIFY (")
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self.append(colspec)
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self.append(")")
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class OracleConstraintCommon(object):
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def get_constraint_name(self, cons):
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# Oracle constraints can't guess their name like other DBs
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if not cons.name:
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raise exceptions.NotSupportedError(
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"Oracle constraint names must be explicitly stated")
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return cons.name
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class OracleConstraintGenerator(OracleConstraintCommon,
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ansisql.ANSIConstraintGenerator):
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pass
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class OracleConstraintDropper(OracleConstraintCommon,
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ansisql.ANSIConstraintDropper):
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pass
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class OracleDialect(ansisql.ANSIDialect):
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columngenerator = OracleColumnGenerator
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columndropper = OracleColumnDropper
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schemachanger = OracleSchemaChanger
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constraintgenerator = OracleConstraintGenerator
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constraintdropper = OracleConstraintDropper
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