/bangkokhotel/lib/python2.5/site-packages/south/db/oracle.py

  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