1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
import re
from .impl import DefaultImpl
from .. import util
class SQLiteImpl(DefaultImpl):
__dialect__ = "sqlite"
transactional_ddl = False
"""SQLite supports transactional DDL, but pysqlite does not:
see: http://bugs.python.org/issue10740
"""
def requires_recreate_in_batch(self, batch_op):
"""Return True if the given :class:`.BatchOperationsImpl`
would need the table to be recreated and copied in order to
proceed.
Normally, only returns True on SQLite when operations other
than add_column are present.
"""
for op in batch_op.batch:
if op[0] not in ("add_column", "create_index", "drop_index"):
return True
else:
return False
def add_constraint(self, const):
# attempt to distinguish between an
# auto-gen constraint and an explicit one
if const._create_rule is None:
raise NotImplementedError(
"No support for ALTER of constraints in SQLite dialect"
)
elif const._create_rule(self):
util.warn(
"Skipping unsupported ALTER for "
"creation of implicit constraint"
)
def drop_constraint(self, const):
if const._create_rule is None:
raise NotImplementedError(
"No support for ALTER of constraints in SQLite dialect"
)
def compare_server_default(
self,
inspector_column,
metadata_column,
rendered_metadata_default,
rendered_inspector_default,
):
if rendered_metadata_default is not None:
rendered_metadata_default = re.sub(
r"^\((.+)\)$", r"\1", rendered_metadata_default
)
rendered_metadata_default = re.sub(
r"^\"?'(.+)'\"?$", r"\1", rendered_metadata_default
)
if rendered_inspector_default is not None:
rendered_inspector_default = re.sub(
r"^\"?'(.+)'\"?$", r"\1", rendered_inspector_default
)
return rendered_inspector_default != rendered_metadata_default
def _guess_if_default_is_unparenthesized_sql_expr(self, expr):
"""Determine if a server default is a SQL expression or a constant.
There are too many assertions that expect server defaults to round-trip
identically without parenthesis added so we will add parens only in
very specific cases.
"""
if not expr:
return False
elif re.match(r"^[0-9\.]$", expr):
return False
elif re.match(r"^'.+'$", expr):
return False
elif re.match(r"^\(.+\)$", expr):
return False
else:
return True
def autogen_column_reflect(self, inspector, table, column_info):
# SQLite expression defaults require parenthesis when sent
# as DDL
if self._guess_if_default_is_unparenthesized_sql_expr(
column_info.get("default", None)
):
column_info["default"] = "(%s)" % (column_info["default"],)
def render_ddl_sql_expr(self, expr, is_server_default=False, **kw):
# SQLite expression defaults require parenthesis when sent
# as DDL
str_expr = super(SQLiteImpl, self).render_ddl_sql_expr(
expr, is_server_default=is_server_default, **kw
)
if (
is_server_default
and self._guess_if_default_is_unparenthesized_sql_expr(str_expr)
):
str_expr = "(%s)" % (str_expr,)
return str_expr
# @compiles(AddColumn, 'sqlite')
# def visit_add_column(element, compiler, **kw):
# return "%s %s" % (
# alter_table(compiler, element.table_name, element.schema),
# add_column(compiler, element.column, **kw)
# )
# def add_column(compiler, column, **kw):
# text = "ADD COLUMN %s" % compiler.get_column_specification(column, **kw)
# need to modify SQLAlchemy so that the CHECK associated with a Boolean
# or Enum gets placed as part of the column constraints, not the Table
# see ticket 98
# for const in column.constraints:
# text += compiler.process(AddConstraint(const))
# return text
|
