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
|
"""
Firebird database specific implementations of changeset classes.
"""
from sqlalchemy.databases import firebird as sa_base
from sqlalchemy.schema import PrimaryKeyConstraint
from migrate import exceptions
from migrate.changeset import ansisql
FBSchemaGenerator = sa_base.FBDDLCompiler
class FBColumnGenerator(FBSchemaGenerator, ansisql.ANSIColumnGenerator):
"""Firebird column generator implementation."""
class FBColumnDropper(ansisql.ANSIColumnDropper):
"""Firebird column dropper implementation."""
def visit_column(self, column):
"""Firebird supports 'DROP col' instead of 'DROP COLUMN col' syntax
Drop primary key and unique constraints if dropped column is referencing it."""
if column.primary_key:
if column.table.primary_key.columns.contains_column(column):
column.table.primary_key.drop()
# TODO: recreate primary key if it references more than this column
for index in column.table.indexes:
# "column in index.columns" causes problems as all
# column objects compare equal and return a SQL expression
if column.name in [col.name for col in index.columns]:
index.drop()
# TODO: recreate index if it references more than this column
for cons in column.table.constraints:
if isinstance(cons,PrimaryKeyConstraint):
# will be deleted only when the column its on
# is deleted!
continue
should_drop = column.name in cons.columns
if should_drop:
self.start_alter_table(column)
self.append("DROP CONSTRAINT ")
self.append(self.preparer.format_constraint(cons))
self.execute()
# TODO: recreate unique constraint if it refenrences more than this column
self.start_alter_table(column)
self.append('DROP %s' % self.preparer.format_column(column))
self.execute()
class FBSchemaChanger(ansisql.ANSISchemaChanger):
"""Firebird schema changer implementation."""
def visit_table(self, table):
"""Rename table not supported"""
raise exceptions.NotSupportedError(
"Firebird does not support renaming tables.")
def _visit_column_name(self, table, column, delta):
self.start_alter_table(table)
col_name = self.preparer.quote(delta.current_name, table.quote)
new_name = self.preparer.format_column(delta.result_column)
self.append('ALTER COLUMN %s TO %s' % (col_name, new_name))
def _visit_column_nullable(self, table, column, delta):
"""Changing NULL is not supported"""
# TODO: http://www.firebirdfaq.org/faq103/
raise exceptions.NotSupportedError(
"Firebird does not support altering NULL bevahior.")
class FBConstraintGenerator(ansisql.ANSIConstraintGenerator):
"""Firebird constraint generator implementation."""
class FBConstraintDropper(ansisql.ANSIConstraintDropper):
"""Firebird constaint dropper implementation."""
def cascade_constraint(self, constraint):
"""Cascading constraints is not supported"""
raise exceptions.NotSupportedError(
"Firebird does not support cascading constraints")
class FBDialect(ansisql.ANSIDialect):
columngenerator = FBColumnGenerator
columndropper = FBColumnDropper
schemachanger = FBSchemaChanger
constraintgenerator = FBConstraintGenerator
constraintdropper = FBConstraintDropper
|
