122 lines
5.0 KiB
Python
122 lines
5.0 KiB
Python
import binascii
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import copy
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import datetime
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import re
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from django.db.backends.base.schema import BaseDatabaseSchemaEditor
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from django.db.utils import DatabaseError
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from django.utils.text import force_text
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class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
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sql_create_column = "ALTER TABLE %(table)s ADD %(column)s %(definition)s"
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sql_alter_column_type = "MODIFY %(column)s %(type)s"
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sql_alter_column_null = "MODIFY %(column)s NULL"
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sql_alter_column_not_null = "MODIFY %(column)s NOT NULL"
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sql_alter_column_default = "MODIFY %(column)s DEFAULT %(default)s"
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sql_alter_column_no_default = "MODIFY %(column)s DEFAULT NULL"
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sql_delete_column = "ALTER TABLE %(table)s DROP COLUMN %(column)s"
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sql_delete_table = "DROP TABLE %(table)s CASCADE CONSTRAINTS"
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def quote_value(self, value):
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if isinstance(value, (datetime.date, datetime.time, datetime.datetime)):
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return "'%s'" % value
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elif isinstance(value, str):
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return "'%s'" % value.replace("\'", "\'\'")
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elif isinstance(value, (bytes, bytearray, memoryview)):
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return "'%s'" % force_text(binascii.hexlify(value))
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elif isinstance(value, bool):
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return "1" if value else "0"
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else:
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return str(value)
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def delete_model(self, model):
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# Run superclass action
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super().delete_model(model)
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# Clean up any autoincrement trigger
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self.execute("""
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DECLARE
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i INTEGER;
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BEGIN
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SELECT COUNT(1) INTO i FROM USER_SEQUENCES
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WHERE SEQUENCE_NAME = '%(sq_name)s';
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IF i = 1 THEN
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EXECUTE IMMEDIATE 'DROP SEQUENCE "%(sq_name)s"';
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END IF;
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END;
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/""" % {'sq_name': self.connection.ops._get_sequence_name(model._meta.db_table)})
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def alter_field(self, model, old_field, new_field, strict=False):
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try:
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super().alter_field(model, old_field, new_field, strict)
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except DatabaseError as e:
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description = str(e)
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# If we're changing type to an unsupported type we need a
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# SQLite-ish workaround
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if 'ORA-22858' in description or 'ORA-22859' in description:
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self._alter_field_type_workaround(model, old_field, new_field)
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else:
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raise
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def _alter_field_type_workaround(self, model, old_field, new_field):
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"""
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Oracle refuses to change from some type to other type.
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What we need to do instead is:
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- Add a nullable version of the desired field with a temporary name
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- Update the table to transfer values from old to new
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- Drop old column
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- Rename the new column and possibly drop the nullable property
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"""
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# Make a new field that's like the new one but with a temporary
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# column name.
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new_temp_field = copy.deepcopy(new_field)
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new_temp_field.null = True
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new_temp_field.column = self._generate_temp_name(new_field.column)
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# Add it
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self.add_field(model, new_temp_field)
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# Explicit data type conversion
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# https://docs.oracle.com/cd/B19306_01/server.102/b14200/sql_elements002.htm#sthref340
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new_value = self.quote_name(old_field.column)
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old_type = old_field.db_type(self.connection)
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if re.match('^N?CLOB', old_type):
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new_value = "TO_CHAR(%s)" % new_value
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old_type = 'VARCHAR2'
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if re.match('^N?VARCHAR2', old_type):
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new_internal_type = new_field.get_internal_type()
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if new_internal_type == 'DateField':
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new_value = "TO_DATE(%s, 'YYYY-MM-DD')" % new_value
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elif new_internal_type == 'DateTimeField':
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new_value = "TO_TIMESTAMP(%s, 'YYYY-MM-DD HH24:MI:SS.FF')" % new_value
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elif new_internal_type == 'TimeField':
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# TimeField are stored as TIMESTAMP with a 1900-01-01 date part.
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new_value = "TO_TIMESTAMP(CONCAT('1900-01-01 ', %s), 'YYYY-MM-DD HH24:MI:SS.FF')" % new_value
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# Transfer values across
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self.execute("UPDATE %s set %s=%s" % (
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self.quote_name(model._meta.db_table),
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self.quote_name(new_temp_field.column),
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new_value,
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))
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# Drop the old field
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self.remove_field(model, old_field)
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# Rename and possibly make the new field NOT NULL
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super().alter_field(model, new_temp_field, new_field)
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def normalize_name(self, name):
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"""
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Get the properly shortened and uppercased identifier as returned by
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quote_name() but without the quotes.
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"""
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nn = self.quote_name(name)
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if nn[0] == '"' and nn[-1] == '"':
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nn = nn[1:-1]
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return nn
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def _generate_temp_name(self, for_name):
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"""Generate temporary names for workarounds that need temp columns."""
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suffix = hex(hash(for_name)).upper()[1:]
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return self.normalize_name(for_name + "_" + suffix)
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def prepare_default(self, value):
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return self.quote_value(value)
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