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import logging
from django.contrib.gis.db.models.fields import GeometryField
from django.db.backends.mysql.schema import DatabaseSchemaEditor
from django.db.utils import OperationalError
logger = logging.getLogger('django.contrib.gis')
class MySQLGISSchemaEditor(DatabaseSchemaEditor):
sql_add_spatial_index = 'CREATE SPATIAL INDEX %(index)s ON %(table)s(%(column)s)'
sql_drop_spatial_index = 'DROP INDEX %(index)s ON %(table)s'
def __init__(self, *args, **kwargs):
super(MySQLGISSchemaEditor, self).__init__(*args, **kwargs)
self.geometry_sql = []
def skip_default(self, field):
return (
super(MySQLGISSchemaEditor, self).skip_default(field) or
# Geometry fields are stored as BLOB/TEXT and can't have defaults.
isinstance(field, GeometryField)
)
def column_sql(self, model, field, include_default=False):
column_sql = super(MySQLGISSchemaEditor, self).column_sql(model, field, include_default)
# MySQL doesn't support spatial indexes on NULL columns
if isinstance(field, GeometryField) and field.spatial_index and not field.null:
qn = self.connection.ops.quote_name
db_table = model._meta.db_table
self.geometry_sql.append(
self.sql_add_spatial_index % {
'index': qn(self._create_spatial_index_name(model, field)),
'table': qn(db_table),
'column': qn(field.column),
}
)
return column_sql
def create_model(self, model):
super(MySQLGISSchemaEditor, self).create_model(model)
self.create_spatial_indexes()
def add_field(self, model, field):
super(MySQLGISSchemaEditor, self).add_field(model, field)
self.create_spatial_indexes()
def remove_field(self, model, field):
if isinstance(field, GeometryField) and field.spatial_index:
qn = self.connection.ops.quote_name
sql = self.sql_drop_spatial_index % {
'index': qn(self._create_spatial_index_name(model, field)),
'table': qn(model._meta.db_table),
}
try:
self.execute(sql)
except OperationalError:
logger.error(
"Couldn't remove spatial index: %s (may be expected "
"if your storage engine doesn't support them).", sql
)
super(MySQLGISSchemaEditor, self).remove_field(model, field)
def _create_spatial_index_name(self, model, field):
return '%s_%s_id' % (model._meta.db_table, field.column)
def create_spatial_indexes(self):
for sql in self.geometry_sql:
try:
self.execute(sql)
except OperationalError:
logger.error(
"Cannot create SPATIAL INDEX %s. Only MyISAM and (as of "
"MySQL 5.7.5) InnoDB support them.", sql
)
self.geometry_sql = []
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