/bangkokhotel/lib/python2.5/site-packages/south/db/oracle.py
Python | 299 lines | 233 code | 30 blank | 36 comment | 31 complexity | a121643f1aed9bf98887c0ec44a7d755 MD5 | raw file
1import os.path
2import sys
3import re
4import warnings
5import cx_Oracle
6
7
8from django.db import connection, models
9from django.db.backends.util import truncate_name
10from django.core.management.color import no_style
11from django.db.models.fields import NOT_PROVIDED
12from django.db.utils import DatabaseError
13
14# In revision r16016 function get_sequence_name has been transformed into
15# method of DatabaseOperations class. To make code backward-compatible we
16# need to handle both situations.
17try:
18 from django.db.backends.oracle.base import get_sequence_name\
19 as original_get_sequence_name
20except ImportError:
21 original_get_sequence_name = None
22
23from south.db import generic
24
25warnings.warn("! WARNING: South's Oracle support is still alpha. "
26 "Be wary of possible bugs.")
27
28class DatabaseOperations(generic.DatabaseOperations):
29 """
30 Oracle implementation of database operations.
31 """
32 backend_name = 'oracle'
33
34 alter_string_set_type = 'ALTER TABLE %(table_name)s MODIFY %(column)s %(type)s %(nullity)s;'
35 alter_string_set_default = 'ALTER TABLE %(table_name)s MODIFY %(column)s DEFAULT %(default)s;'
36 add_column_string = 'ALTER TABLE %s ADD %s;'
37 delete_column_string = 'ALTER TABLE %s DROP COLUMN %s;'
38 add_constraint_string = 'ALTER TABLE %(table_name)s ADD CONSTRAINT %(constraint)s %(clause)s'
39
40 allows_combined_alters = False
41 has_booleans = False
42
43 constraints_dict = {
44 'P': 'PRIMARY KEY',
45 'U': 'UNIQUE',
46 'C': 'CHECK',
47 'R': 'FOREIGN KEY'
48 }
49
50 def get_sequence_name(self, table_name):
51 if original_get_sequence_name is None:
52 return self._get_connection().ops._get_sequence_name(table_name)
53 else:
54 return original_get_sequence_name(table_name)
55
56 #TODO: This will cause very obscure bugs if anyone uses a column name or string value
57 # that looks like a column definition (with 'CHECK', 'DEFAULT' and/or 'NULL' in it)
58 # e.g. "CHECK MATE" varchar(10) DEFAULT 'NULL'
59 def adj_column_sql(self, col):
60 # Syntax fixes -- Oracle is picky about clause order
61 col = re.sub('(?P<constr>CHECK \(.*\))(?P<any>.*)(?P<default>DEFAULT \d+)',
62 lambda mo: '%s %s%s'%(mo.group('default'), mo.group('constr'), mo.group('any')), col) #syntax fix for boolean/integer field only
63 col = re.sub('(?P<not_null>(NOT )?NULL) (?P<misc>(.* )?)(?P<default>DEFAULT.+)',
64 lambda mo: '%s %s %s'%(mo.group('default'),mo.group('not_null'),mo.group('misc') or ''), col) #fix order of NULL/NOT NULL and DEFAULT
65 return col
66
67 def check_meta(self, table_name):
68 return table_name in [ m._meta.db_table for m in models.get_models() ] #caching provided by Django
69
70 def normalize_name(self, name):
71 """
72 Get the properly shortened and uppercased identifier as returned by quote_name(), but without the actual quotes.
73 """
74 nn = self.quote_name(name)
75 if nn[0] == '"' and nn[-1] == '"':
76 nn = nn[1:-1]
77 return nn
78
79 @generic.invalidate_table_constraints
80 def create_table(self, table_name, fields):
81 qn = self.quote_name(table_name)
82 columns = []
83 autoinc_sql = ''
84
85 for field_name, field in fields:
86 col = self.column_sql(table_name, field_name, field)
87 if not col:
88 continue
89 col = self.adj_column_sql(col)
90
91 columns.append(col)
92 if isinstance(field, models.AutoField):
93 autoinc_sql = connection.ops.autoinc_sql(table_name, field_name)
94
95 sql = 'CREATE TABLE %s (%s);' % (qn, ', '.join([col for col in columns]))
96 self.execute(sql)
97 if autoinc_sql:
98 self.execute(autoinc_sql[0])
99 self.execute(autoinc_sql[1])
100
101 @generic.invalidate_table_constraints
102 def delete_table(self, table_name, cascade=True):
103 qn = self.quote_name(table_name)
104
105 # Note: PURGE is not valid syntax for Oracle 9i (it was added in 10)
106 if cascade:
107 self.execute('DROP TABLE %s CASCADE CONSTRAINTS;' % qn)
108 else:
109 self.execute('DROP TABLE %s;' % qn)
110
111 # If the table has an AutoField a sequence was created.
112 sequence_sql = """
113DECLARE
114 i INTEGER;
115BEGIN
116 SELECT COUNT(*) INTO i FROM USER_CATALOG
117 WHERE TABLE_NAME = '%(sq_name)s' AND TABLE_TYPE = 'SEQUENCE';
118 IF i = 1 THEN
119 EXECUTE IMMEDIATE 'DROP SEQUENCE "%(sq_name)s"';
120 END IF;
121END;
122/""" % {'sq_name': self.get_sequence_name(table_name)}
123 self.execute(sequence_sql)
124
125 @generic.invalidate_table_constraints
126 def alter_column(self, table_name, name, field, explicit_name=True):
127
128 if self.dry_run:
129 if self.debug:
130 print ' - no dry run output for alter_column() due to dynamic DDL, sorry'
131 return
132
133 qn = self.quote_name(table_name)
134
135 # hook for the field to do any resolution prior to it's attributes being queried
136 if hasattr(field, 'south_init'):
137 field.south_init()
138 field = self._field_sanity(field)
139
140 # Add _id or whatever if we need to
141 field.set_attributes_from_name(name)
142 if not explicit_name:
143 name = field.column
144 qn_col = self.quote_name(name)
145
146 # First, change the type
147 # This will actually also add any CHECK constraints needed,
148 # since e.g. 'type' for a BooleanField is 'NUMBER(1) CHECK (%(qn_column)s IN (0,1))'
149 params = {
150 'table_name':qn,
151 'column': qn_col,
152 'type': self._db_type_for_alter_column(field),
153 'nullity': 'NOT NULL',
154 'default': 'NULL'
155 }
156 if field.null:
157 params['nullity'] = 'NULL'
158
159 if not field.null and field.has_default():
160 params['default'] = self._default_value_workaround(field.get_default())
161
162 sql_templates = [
163 (self.alter_string_set_type, params),
164 (self.alter_string_set_default, params.copy()),
165 ]
166
167 # drop CHECK constraints. Make sure this is executed before the ALTER TABLE statements
168 # generated above, since those statements recreate the constraints we delete here.
169 check_constraints = self._constraints_affecting_columns(table_name, [name], "CHECK")
170 for constraint in check_constraints:
171 self.execute(self.delete_check_sql % {
172 'table': self.quote_name(table_name),
173 'constraint': self.quote_name(constraint),
174 })
175
176 for sql_template, params in sql_templates:
177 try:
178 self.execute(sql_template % params)
179 except DatabaseError, exc:
180 description = str(exc)
181 # Oracle complains if a column is already NULL/NOT NULL
182 if 'ORA-01442' in description or 'ORA-01451' in description:
183 # so we just drop NULL/NOT NULL part from target sql and retry
184 params['nullity'] = ''
185 sql = sql_template % params
186 self.execute(sql)
187 # Oracle also has issues if we try to change a regular column
188 # to a LOB or vice versa (also REF, object, VARRAY or nested
189 # table, but these don't come up much in Django apps)
190 elif 'ORA-22858' in description or 'ORA-22859' in description:
191 self._alter_column_lob_workaround(table_name, name, field)
192 else:
193 raise
194
195 def _alter_column_lob_workaround(self, table_name, name, field):
196 """
197 Oracle refuses to change a column type from/to LOB to/from a regular
198 column. In Django, this shows up when the field is changed from/to
199 a TextField.
200 What we need to do instead is:
201 - Rename the original column
202 - Add the desired field as new
203 - Update the table to transfer values from old to new
204 - Drop old column
205 """
206 renamed = self._generate_temp_name(name)
207 self.rename_column(table_name, name, renamed)
208 self.add_column(table_name, name, field, keep_default=False)
209 self.execute("UPDATE %s set %s=%s" % (
210 self.quote_name(table_name),
211 self.quote_name(name),
212 self.quote_name(renamed),
213 ))
214 self.delete_column(table_name, renamed)
215
216 def _generate_temp_name(self, for_name):
217 suffix = hex(hash(for_name)).upper()[1:]
218 return self.normalize_name(for_name + "_" + suffix)
219
220 @generic.copy_column_constraints #TODO: Appears to be nulled by the delete decorator below...
221 @generic.delete_column_constraints
222 def rename_column(self, table_name, old, new):
223 if old == new:
224 # Short-circuit out
225 return []
226 self.execute('ALTER TABLE %s RENAME COLUMN %s TO %s;' % (
227 self.quote_name(table_name),
228 self.quote_name(old),
229 self.quote_name(new),
230 ))
231
232 @generic.invalidate_table_constraints
233 def add_column(self, table_name, name, field, keep_default=True):
234 sql = self.column_sql(table_name, name, field)
235 sql = self.adj_column_sql(sql)
236
237 if sql:
238 params = (
239 self.quote_name(table_name),
240 sql
241 )
242 sql = self.add_column_string % params
243 self.execute(sql)
244
245 # Now, drop the default if we need to
246 if not keep_default and field.default is not None:
247 field.default = NOT_PROVIDED
248 self.alter_column(table_name, name, field, explicit_name=False)
249
250 def delete_column(self, table_name, name):
251 return super(DatabaseOperations, self).delete_column(self.quote_name(table_name), name)
252
253 def lookup_constraint(self, db_name, table_name, column_name=None):
254 if column_name:
255 # Column names in the constraint cache come from the database,
256 # make sure we use the properly shortened/uppercased version
257 # for lookup.
258 column_name = self.normalize_name(column_name)
259 return super(DatabaseOperations, self).lookup_constraint(db_name, table_name, column_name)
260
261 def _constraints_affecting_columns(self, table_name, columns, type="UNIQUE"):
262 if columns:
263 columns = [self.normalize_name(c) for c in columns]
264 return super(DatabaseOperations, self)._constraints_affecting_columns(table_name, columns, type)
265
266 def _field_sanity(self, field):
267 """
268 This particular override stops us sending DEFAULTs for BooleanField.
269 """
270 if isinstance(field, models.BooleanField) and field.has_default():
271 field.default = int(field.to_python(field.get_default()))
272 return field
273
274 def _default_value_workaround(self, value):
275 from datetime import date,time,datetime
276 if isinstance(value, (date,time,datetime)):
277 return "'%s'" % value
278 else:
279 return super(DatabaseOperations, self)._default_value_workaround(value)
280
281 def _fill_constraint_cache(self, db_name, table_name):
282 self._constraint_cache.setdefault(db_name, {})
283 self._constraint_cache[db_name][table_name] = {}
284
285 rows = self.execute("""
286 SELECT user_cons_columns.constraint_name,
287 user_cons_columns.column_name,
288 user_constraints.constraint_type
289 FROM user_constraints
290 JOIN user_cons_columns ON
291 user_constraints.table_name = user_cons_columns.table_name AND
292 user_constraints.constraint_name = user_cons_columns.constraint_name
293 WHERE user_constraints.table_name = '%s'
294 """ % self.normalize_name(table_name))
295
296 for constraint, column, kind in rows:
297 self._constraint_cache[db_name][table_name].setdefault(column, set())
298 self._constraint_cache[db_name][table_name][column].add((self.constraints_dict[kind], constraint))
299 return