338 lines
12 KiB
Python
338 lines
12 KiB
Python
"""
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DB2 database specific implementations of changeset classes.
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"""
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import logging
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from ibm_db_sa import base
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from sqlalchemy.schema import (AddConstraint,
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CreateIndex,
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DropConstraint)
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from sqlalchemy.schema import (Index,
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PrimaryKeyConstraint,
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UniqueConstraint)
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from migrate.changeset import ansisql
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from migrate.changeset import constraint
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from migrate.changeset import util
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from migrate import exceptions
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LOG = logging.getLogger(__name__)
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IBMDBSchemaGenerator = base.IBM_DBDDLCompiler
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def get_server_version_info(dialect):
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"""Returns the DB2 server major and minor version as a list of ints."""
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return [int(ver_token) for ver_token in dialect.dbms_ver.split('.')[0:2]]
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def is_unique_constraint_with_null_columns_supported(dialect):
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"""Checks to see if the DB2 version is at least 10.5.
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This is needed for checking if unique constraints with null columns
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are supported.
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"""
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return get_server_version_info(dialect) >= [10, 5]
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class IBMDBColumnGenerator(IBMDBSchemaGenerator,
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ansisql.ANSIColumnGenerator):
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def visit_column(self, column):
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nullable = True
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if not column.nullable:
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nullable = False
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column.nullable = True
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table = self.start_alter_table(column)
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self.append("ADD COLUMN ")
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self.append(self.get_column_specification(column))
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for cons in column.constraints:
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self.traverse_single(cons)
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if column.default is not None:
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self.traverse_single(column.default)
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self.execute()
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#ALTER TABLE STATEMENTS
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if not nullable:
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self.start_alter_table(column)
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self.append("ALTER COLUMN %s SET NOT NULL" %
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self.preparer.format_column(column))
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self.execute()
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self.append("CALL SYSPROC.ADMIN_CMD('REORG TABLE %s')" %
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self.preparer.format_table(table))
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self.execute()
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# add indexes and unique constraints
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if column.index_name:
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Index(column.index_name, column).create()
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elif column.unique_name:
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constraint.UniqueConstraint(column,
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name=column.unique_name).create()
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# SA bounds FK constraints to table, add manually
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for fk in column.foreign_keys:
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self.add_foreignkey(fk.constraint)
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# add primary key constraint if needed
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if column.primary_key_name:
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pk = constraint.PrimaryKeyConstraint(
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column, name=column.primary_key_name)
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pk.create()
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self.append("COMMIT")
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self.execute()
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self.append("CALL SYSPROC.ADMIN_CMD('REORG TABLE %s')" %
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self.preparer.format_table(table))
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self.execute()
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class IBMDBColumnDropper(ansisql.ANSIColumnDropper):
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def visit_column(self, column):
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"""Drop a column from its table.
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:param column: the column object
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:type column: :class:`sqlalchemy.Column`
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"""
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#table = self.start_alter_table(column)
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super(IBMDBColumnDropper, self).visit_column(column)
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self.append("CALL SYSPROC.ADMIN_CMD('REORG TABLE %s')" %
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self.preparer.format_table(column.table))
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self.execute()
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class IBMDBSchemaChanger(IBMDBSchemaGenerator, ansisql.ANSISchemaChanger):
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def visit_table(self, table):
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"""Rename a table; #38. Other ops aren't supported."""
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self._rename_table(table)
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self.append("TO %s" % self.preparer.quote(table.new_name))
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self.execute()
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self.append("COMMIT")
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self.execute()
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def _rename_table(self, table):
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self.append("RENAME TABLE %s " % self.preparer.format_table(table))
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def visit_index(self, index):
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if hasattr(self, '_index_identifier'):
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# SA >= 0.6.5, < 0.8
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old_name = self.preparer.quote(
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self._index_identifier(index.name))
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new_name = self.preparer.quote(
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self._index_identifier(index.new_name))
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else:
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# SA >= 0.8
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class NewName(object):
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"""Map obj.name -> obj.new_name"""
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def __init__(self, index):
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self.name = index.new_name
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self._obj = index
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def __getattr__(self, attr):
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if attr == 'name':
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return getattr(self, attr)
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return getattr(self._obj, attr)
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old_name = self._prepared_index_name(index)
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new_name = self._prepared_index_name(NewName(index))
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self.append("RENAME INDEX %s TO %s" % (old_name, new_name))
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self.execute()
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self.append("COMMIT")
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self.execute()
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def _run_subvisit(self, delta, func, start_alter=True):
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"""Runs visit method based on what needs to be changed on column"""
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table = delta.table
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if start_alter:
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self.start_alter_table(table)
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ret = func(table,
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self.preparer.quote(delta.current_name),
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delta)
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self.execute()
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self._reorg_table(self.preparer.format_table(delta.table))
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def _reorg_table(self, delta):
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self.append("CALL SYSPROC.ADMIN_CMD('REORG TABLE %s')" % delta)
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self.execute()
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def visit_column(self, delta):
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keys = delta.keys()
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tr = self.connection.begin()
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column = delta.result_column.copy()
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if 'type' in keys:
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try:
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self._run_subvisit(delta, self._visit_column_change, False)
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except Exception as e:
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LOG.warn("Unable to change the column type. Error: %s" % e)
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if column.primary_key and 'primary_key' not in keys:
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try:
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self._run_subvisit(delta, self._visit_primary_key)
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except Exception as e:
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LOG.warn("Unable to add primary key. Error: %s" % e)
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if 'nullable' in keys:
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self._run_subvisit(delta, self._visit_column_nullable)
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if 'server_default' in keys:
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self._run_subvisit(delta, self._visit_column_default)
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if 'primary_key' in keys:
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self._run_subvisit(delta, self._visit_primary_key)
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self._run_subvisit(delta, self._visit_unique_constraint)
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if 'name' in keys:
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try:
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self._run_subvisit(delta, self._visit_column_name, False)
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except Exception as e:
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LOG.warn("Unable to change column %(name)s. Error: %(error)s" %
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{'name': delta.current_name, 'error': e})
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self._reorg_table(self.preparer.format_table(delta.table))
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self.append("COMMIT")
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self.execute()
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tr.commit()
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def _visit_unique_constraint(self, table, col_name, delta):
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# Add primary key to the current column
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self.append("ADD CONSTRAINT %s " % col_name)
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self.append("UNIQUE (%s)" % col_name)
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def _visit_primary_key(self, table, col_name, delta):
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# Add primary key to the current column
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self.append("ADD PRIMARY KEY (%s)" % col_name)
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def _visit_column_name(self, table, col_name, delta):
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column = delta.result_column.copy()
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# Delete the primary key before renaming the column
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if column.primary_key:
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try:
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self.start_alter_table(table)
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self.append("DROP PRIMARY KEY")
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self.execute()
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except Exception:
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LOG.debug("Continue since Primary key does not exist.")
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self.start_alter_table(table)
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new_name = self.preparer.format_column(delta.result_column)
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self.append("RENAME COLUMN %s TO %s" % (col_name, new_name))
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if column.primary_key:
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# execute the rename before adding primary key back
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self.execute()
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self.start_alter_table(table)
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self.append("ADD PRIMARY KEY (%s)" % new_name)
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def _visit_column_nullable(self, table, col_name, delta):
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self.append("ALTER COLUMN %s " % col_name)
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nullable = delta['nullable']
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if nullable:
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self.append("DROP NOT NULL")
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else:
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self.append("SET NOT NULL")
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def _visit_column_default(self, table, col_name, delta):
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default_text = self.get_column_default_string(delta.result_column)
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self.append("ALTER COLUMN %s " % col_name)
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if default_text is None:
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self.append("DROP DEFAULT")
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else:
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self.append("SET WITH DEFAULT %s" % default_text)
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def _visit_column_change(self, table, col_name, delta):
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column = delta.result_column.copy()
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# Delete the primary key before
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if column.primary_key:
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try:
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self.start_alter_table(table)
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self.append("DROP PRIMARY KEY")
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self.execute()
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except Exception:
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LOG.debug("Continue since Primary key does not exist.")
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# Delete the identity before
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try:
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self.start_alter_table(table)
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self.append("ALTER COLUMN %s DROP IDENTITY" % col_name)
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self.execute()
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except Exception:
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LOG.debug("Continue since identity does not exist.")
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column.default = None
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if not column.table:
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column.table = delta.table
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self.start_alter_table(table)
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self.append("ALTER COLUMN %s " % col_name)
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self.append("SET DATA TYPE ")
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type_text = self.dialect.type_compiler.process(
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delta.result_column.type)
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self.append(type_text)
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class IBMDBConstraintGenerator(ansisql.ANSIConstraintGenerator):
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def _visit_constraint(self, constraint):
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constraint.name = self.get_constraint_name(constraint)
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if (isinstance(constraint, UniqueConstraint) and
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is_unique_constraint_with_null_columns_supported(
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self.dialect)):
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for column in constraint:
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if column.nullable:
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constraint.exclude_nulls = True
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break
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if getattr(constraint, 'exclude_nulls', None):
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index = Index(constraint.name,
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*(column for column in constraint),
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unique=True)
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sql = self.process(CreateIndex(index))
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sql += ' EXCLUDE NULL KEYS'
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else:
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sql = self.process(AddConstraint(constraint))
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self.append(sql)
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self.execute()
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class IBMDBConstraintDropper(ansisql.ANSIConstraintDropper,
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ansisql.ANSIConstraintCommon):
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def _visit_constraint(self, constraint):
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constraint.name = self.get_constraint_name(constraint)
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if (isinstance(constraint, UniqueConstraint) and
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is_unique_constraint_with_null_columns_supported(
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self.dialect)):
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for column in constraint:
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if column.nullable:
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constraint.exclude_nulls = True
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break
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if getattr(constraint, 'exclude_nulls', None):
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if hasattr(self, '_index_identifier'):
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# SA >= 0.6.5, < 0.8
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index_name = self.preparer.quote(
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self._index_identifier(constraint.name))
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else:
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# SA >= 0.8
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index_name = self._prepared_index_name(constraint)
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sql = 'DROP INDEX %s ' % index_name
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else:
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sql = self.process(DropConstraint(constraint,
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cascade=constraint.cascade))
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self.append(sql)
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self.execute()
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def visit_migrate_primary_key_constraint(self, constraint):
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self.start_alter_table(constraint.table)
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self.append("DROP PRIMARY KEY")
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self.execute()
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class IBMDBDialect(ansisql.ANSIDialect):
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columngenerator = IBMDBColumnGenerator
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columndropper = IBMDBColumnDropper
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schemachanger = IBMDBSchemaChanger
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constraintgenerator = IBMDBConstraintGenerator
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constraintdropper = IBMDBConstraintDropper
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