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Drying get_sql methods

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Some updates to Nullable documentation
This commit is contained in:
Roy Belio 2019-06-24 18:54:55 +03:00
parent 3ba44608f3
commit bcc4c29d10
2 changed files with 19 additions and 29 deletions
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5
docs/field_types.md
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@ -121,8 +121,7 @@ db.select('SELECT * FROM $db.event', model_class=Event)
Working with nullable fields Working with nullable fields
---------------------------- ----------------------------
From [some time](https://github.com/yandex/ClickHouse/pull/70) ClickHouse provides a NULL value support. [ClickHouse provides a NULL value support](https://clickhouse.yandex/docs/en/data_types/nullable).
Also see some information [here](https://github.com/yandex/ClickHouse/blob/master/dbms/tests/queries/0_stateless/00395_nullable.sql).
Wrapping another field in a `NullableField` makes it possible to assign `None` to that field. For example: Wrapping another field in a `NullableField` makes it possible to assign `None` to that field. For example:
@ -148,6 +147,8 @@ to `None`.
NOTE: `ArrayField` of `NullableField` is not supported. Also `EnumField` cannot be nullable. NOTE: `ArrayField` of `NullableField` is not supported. Also `EnumField` cannot be nullable.
NOTE: Using `Nullable` almost always negatively affects performance, keep this in mind when designing your databases.
Working with field compression codecs Working with field compression codecs
------------------------------------- -------------------------------------
Besides default data compression, defined in server settings, per-field specification is also available. Besides default data compression, defined in server settings, per-field specification is also available.

29
src/infi/clickhouse_orm/fields.py
View File

@ -76,15 +76,20 @@ class Field(object):
''' '''
sql = self.db_type sql = self.db_type
if with_default_expression: if with_default_expression:
sql += self._extra_params(db)
return sql
def _extra_params(self, db):
sql = ''
if self.alias: if self.alias:
sql += ' ALIAS %s' % self.alias sql += ' ALIAS %s' % self.alias
elif self.materialized: elif self.materialized:
sql += ' MATERIALIZED %s' % self.materialized sql += ' MATERIALIZED %s' % self.materialized
else: elif self.default:
default = self.to_db_string(self.default) default = self.to_db_string(self.default)
sql += ' DEFAULT %s' % default sql += ' DEFAULT %s' % default
if self.codec and db and db.has_codec_support: if self.codec and db and db.has_codec_support:
sql+= ' CODEC(%s)' % self.codec sql += ' CODEC(%s)' % self.codec
return sql return sql
def isinstance(self, types): def isinstance(self, types):
@ -511,15 +516,7 @@ class NullableField(Field):
def get_sql(self, with_default_expression=True, db=None): def get_sql(self, with_default_expression=True, db=None):
sql = 'Nullable(%s)' % self.inner_field.get_sql(with_default_expression=False, db=db) sql = 'Nullable(%s)' % self.inner_field.get_sql(with_default_expression=False, db=db)
if with_default_expression: if with_default_expression:
if self.alias: sql += self._extra_params(db)
sql += ' ALIAS %s' % self.alias
elif self.materialized:
sql += ' MATERIALIZED %s' % self.materialized
elif self.default:
default = self.to_db_string(self.default)
sql += ' DEFAULT %s' % default
if self.codec and db and db.has_codec_support:
sql+= ' CODEC(%s)' % self.codec
return sql return sql
@ -549,13 +546,5 @@ class LowCardinalityField(Field):
sql = self.inner_field.get_sql(with_default_expression=False) sql = self.inner_field.get_sql(with_default_expression=False)
logger.warning('LowCardinalityField not supported on clickhouse-server version < 19.0 using {} as fallback'.format(self.inner_field.__class__.__name__)) logger.warning('LowCardinalityField not supported on clickhouse-server version < 19.0 using {} as fallback'.format(self.inner_field.__class__.__name__))
if with_default_expression: if with_default_expression:
if self.alias: sql += self._extra_params(db)
sql += ' ALIAS %s' % self.alias
elif self.materialized:
sql += ' MATERIALIZED %s' % self.materialized
elif self.default:
default = self.to_db_string(self.default)
sql += ' DEFAULT %s' % default
if self.codec and db and db.has_codec_support:
sql+= ' CODEC(%s)' % self.codec
return sql return sql