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
|
# engine/ddl.py
# Copyright (C) 2009 Michael Bayer mike_mp@zzzcomputing.com
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Routines to handle CREATE/DROP workflow."""
from sqlalchemy import engine, schema
from sqlalchemy.sql import util as sql_util
class DDLBase(schema.SchemaVisitor):
def __init__(self, connection):
self.connection = connection
class SchemaGenerator(DDLBase):
def __init__(self, dialect, connection, checkfirst=False, tables=None, **kwargs):
super(SchemaGenerator, self).__init__(connection, **kwargs)
self.checkfirst = checkfirst
self.tables = tables and set(tables) or None
self.preparer = dialect.identifier_preparer
self.dialect = dialect
def _can_create(self, table):
self.dialect.validate_identifier(table.name)
if table.schema:
self.dialect.validate_identifier(table.schema)
return not self.checkfirst or not self.dialect.has_table(self.connection, table.name, schema=table.schema)
def visit_metadata(self, metadata):
if self.tables:
tables = self.tables
else:
tables = metadata.tables.values()
collection = [t for t in sql_util.sort_tables(tables) if self._can_create(t)]
for listener in metadata.ddl_listeners['before-create']:
listener('before-create', metadata, self.connection, tables=collection)
for table in collection:
self.traverse_single(table)
for listener in metadata.ddl_listeners['after-create']:
listener('after-create', metadata, self.connection, tables=collection)
def visit_table(self, table):
for listener in table.ddl_listeners['before-create']:
listener('before-create', table, self.connection)
for column in table.columns:
if column.default is not None:
self.traverse_single(column.default)
self.connection.execute(schema.CreateTable(table))
if hasattr(table, 'indexes'):
for index in table.indexes:
self.traverse_single(index)
for listener in table.ddl_listeners['after-create']:
listener('after-create', table, self.connection)
def visit_sequence(self, sequence):
if self.dialect.supports_sequences:
if ((not self.dialect.sequences_optional or
not sequence.optional) and
(not self.checkfirst or
not self.dialect.has_sequence(self.connection, sequence.name))):
self.connection.execute(schema.CreateSequence(sequence))
def visit_index(self, index):
self.connection.execute(schema.CreateIndex(index))
class SchemaDropper(DDLBase):
def __init__(self, dialect, connection, checkfirst=False, tables=None, **kwargs):
super(SchemaDropper, self).__init__(connection, **kwargs)
self.checkfirst = checkfirst
self.tables = tables
self.preparer = dialect.identifier_preparer
self.dialect = dialect
def visit_metadata(self, metadata):
if self.tables:
tables = self.tables
else:
tables = metadata.tables.values()
collection = [t for t in reversed(sql_util.sort_tables(tables)) if self._can_drop(t)]
for listener in metadata.ddl_listeners['before-drop']:
listener('before-drop', metadata, self.connection, tables=collection)
for table in collection:
self.traverse_single(table)
for listener in metadata.ddl_listeners['after-drop']:
listener('after-drop', metadata, self.connection, tables=collection)
def _can_drop(self, table):
self.dialect.validate_identifier(table.name)
if table.schema:
self.dialect.validate_identifier(table.schema)
return not self.checkfirst or self.dialect.has_table(self.connection, table.name, schema=table.schema)
def visit_index(self, index):
self.connection.execute(schema.DropIndex(index))
def visit_table(self, table):
for listener in table.ddl_listeners['before-drop']:
listener('before-drop', table, self.connection)
for column in table.columns:
if column.default is not None:
self.traverse_single(column.default)
self.connection.execute(schema.DropTable(table))
for listener in table.ddl_listeners['after-drop']:
listener('after-drop', table, self.connection)
def visit_sequence(self, sequence):
if self.dialect.supports_sequences:
if ((not self.dialect.sequences_optional or
not sequence.optional) and
(not self.checkfirst or
self.dialect.has_sequence(self.connection, sequence.name))):
self.connection.execute(schema.DropSequence(sequence))
|
