412 lines
17 KiB
Python
412 lines
17 KiB
Python
"""
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Oracle database backend for Django.
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Requires cx_Oracle: http://www.python.net/crew/atuining/cx_Oracle/
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"""
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import os
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import datetime
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import time
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from django.db.backends import *
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from django.db.backends.oracle import query
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from django.db.backends.oracle.client import DatabaseClient
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from django.db.backends.oracle.creation import DatabaseCreation
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from django.db.backends.oracle.introspection import DatabaseIntrospection
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from django.utils.encoding import smart_str, force_unicode
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# Oracle takes client-side character set encoding from the environment.
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os.environ['NLS_LANG'] = '.UTF8'
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try:
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import cx_Oracle as Database
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except ImportError, e:
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from django.core.exceptions import ImproperlyConfigured
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raise ImproperlyConfigured("Error loading cx_Oracle module: %s" % e)
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DatabaseError = Database.Error
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IntegrityError = Database.IntegrityError
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class DatabaseFeatures(BaseDatabaseFeatures):
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empty_fetchmany_value = ()
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needs_datetime_string_cast = False
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uses_custom_query_class = True
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interprets_empty_strings_as_nulls = True
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class DatabaseOperations(BaseDatabaseOperations):
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def autoinc_sql(self, table, column):
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# To simulate auto-incrementing primary keys in Oracle, we have to
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# create a sequence and a trigger.
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sq_name = get_sequence_name(table)
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tr_name = get_trigger_name(table)
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tbl_name = self.quote_name(table)
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col_name = self.quote_name(column)
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sequence_sql = 'CREATE SEQUENCE %s;' % sq_name
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trigger_sql = """
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CREATE OR REPLACE TRIGGER %(tr_name)s
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BEFORE INSERT ON %(tbl_name)s
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FOR EACH ROW
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WHEN (new.%(col_name)s IS NULL)
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BEGIN
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SELECT %(sq_name)s.nextval
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INTO :new.%(col_name)s FROM dual;
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END;
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/""" % locals()
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return sequence_sql, trigger_sql
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def date_extract_sql(self, lookup_type, field_name):
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# http://download-east.oracle.com/docs/cd/B10501_01/server.920/a96540/functions42a.htm#1017163
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return "EXTRACT(%s FROM %s)" % (lookup_type, field_name)
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def date_trunc_sql(self, lookup_type, field_name):
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# Oracle uses TRUNC() for both dates and numbers.
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# http://download-east.oracle.com/docs/cd/B10501_01/server.920/a96540/functions155a.htm#SQLRF06151
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if lookup_type == 'day':
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sql = 'TRUNC(%s)' % field_name
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else:
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sql = "TRUNC(%s, '%s')" % (field_name, lookup_type)
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return sql
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def datetime_cast_sql(self):
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return "TO_TIMESTAMP(%s, 'YYYY-MM-DD HH24:MI:SS.FF')"
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def deferrable_sql(self):
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return " DEFERRABLE INITIALLY DEFERRED"
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def drop_sequence_sql(self, table):
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return "DROP SEQUENCE %s;" % self.quote_name(get_sequence_name(table))
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def field_cast_sql(self, db_type):
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if db_type and db_type.endswith('LOB'):
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return "DBMS_LOB.SUBSTR(%s)"
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else:
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return "%s"
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def last_insert_id(self, cursor, table_name, pk_name):
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sq_name = util.truncate_name(table_name, self.max_name_length() - 3)
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cursor.execute('SELECT %s_sq.currval FROM dual' % sq_name)
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return cursor.fetchone()[0]
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def lookup_cast(self, lookup_type):
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if lookup_type in ('iexact', 'icontains', 'istartswith', 'iendswith'):
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return "UPPER(%s)"
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return "%s"
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def max_name_length(self):
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return 30
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def query_class(self, DefaultQueryClass):
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return query.query_class(DefaultQueryClass, Database)
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def quote_name(self, name):
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# SQL92 requires delimited (quoted) names to be case-sensitive. When
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# not quoted, Oracle has case-insensitive behavior for identifiers, but
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# always defaults to uppercase.
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# We simplify things by making Oracle identifiers always uppercase.
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if not name.startswith('"') and not name.endswith('"'):
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name = '"%s"' % util.truncate_name(name.upper(), self.max_name_length())
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return name.upper()
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def random_function_sql(self):
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return "DBMS_RANDOM.RANDOM"
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def regex_lookup_9(self, lookup_type):
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raise NotImplementedError("Regexes are not supported in Oracle before version 10g.")
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def regex_lookup_10(self, lookup_type):
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if lookup_type == 'regex':
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match_option = "'c'"
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else:
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match_option = "'i'"
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return 'REGEXP_LIKE(%%s, %%s, %s)' % match_option
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def regex_lookup(self, lookup_type):
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# If regex_lookup is called before it's been initialized, then create
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# a cursor to initialize it and recur.
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from django.db import connection
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connection.cursor()
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return connection.ops.regex_lookup(lookup_type)
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def sql_flush(self, style, tables, sequences):
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# Return a list of 'TRUNCATE x;', 'TRUNCATE y;',
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# 'TRUNCATE z;'... style SQL statements
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if tables:
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# Oracle does support TRUNCATE, but it seems to get us into
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# FK referential trouble, whereas DELETE FROM table works.
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sql = ['%s %s %s;' % \
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(style.SQL_KEYWORD('DELETE'),
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style.SQL_KEYWORD('FROM'),
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style.SQL_FIELD(self.quote_name(table))
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) for table in tables]
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# Since we've just deleted all the rows, running our sequence
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# ALTER code will reset the sequence to 0.
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for sequence_info in sequences:
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sequence_name = get_sequence_name(sequence_info['table'])
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table_name = self.quote_name(sequence_info['table'])
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column_name = self.quote_name(sequence_info['column'] or 'id')
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query = _get_sequence_reset_sql() % {'sequence': sequence_name,
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'table': table_name,
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'column': column_name}
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sql.append(query)
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return sql
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else:
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return []
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def sequence_reset_sql(self, style, model_list):
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from django.db import models
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output = []
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query = _get_sequence_reset_sql()
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for model in model_list:
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for f in model._meta.local_fields:
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if isinstance(f, models.AutoField):
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table_name = self.quote_name(model._meta.db_table)
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sequence_name = get_sequence_name(model._meta.db_table)
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column_name = self.quote_name(f.column)
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output.append(query % {'sequence': sequence_name,
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'table': table_name,
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'column': column_name})
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break # Only one AutoField is allowed per model, so don't bother continuing.
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for f in model._meta.many_to_many:
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table_name = self.quote_name(f.m2m_db_table())
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sequence_name = get_sequence_name(f.m2m_db_table())
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column_name = self.quote_name('id')
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output.append(query % {'sequence': sequence_name,
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'table': table_name,
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'column': column_name})
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return output
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def start_transaction_sql(self):
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return ''
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def tablespace_sql(self, tablespace, inline=False):
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return "%sTABLESPACE %s" % ((inline and "USING INDEX " or ""), self.quote_name(tablespace))
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def value_to_db_time(self, value):
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if value is None:
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return None
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if isinstance(value, basestring):
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return datetime.datetime(*(time.strptime(value, '%H:%M:%S')[:6]))
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return datetime.datetime(1900, 1, 1, value.hour, value.minute,
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value.second, value.microsecond)
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def year_lookup_bounds_for_date_field(self, value):
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first = '%s-01-01'
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second = '%s-12-31'
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return [first % value, second % value]
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class DatabaseWrapper(BaseDatabaseWrapper):
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operators = {
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'exact': '= %s',
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'iexact': '= UPPER(%s)',
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'contains': "LIKEC %s ESCAPE '\\'",
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'icontains': "LIKEC UPPER(%s) ESCAPE '\\'",
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'gt': '> %s',
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'gte': '>= %s',
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'lt': '< %s',
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'lte': '<= %s',
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'startswith': "LIKEC %s ESCAPE '\\'",
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'endswith': "LIKEC %s ESCAPE '\\'",
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'istartswith': "LIKEC UPPER(%s) ESCAPE '\\'",
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'iendswith': "LIKEC UPPER(%s) ESCAPE '\\'",
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}
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oracle_version = None
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def __init__(self, *args, **kwargs):
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super(DatabaseWrapper, self).__init__(*args, **kwargs)
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self.features = DatabaseFeatures()
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self.ops = DatabaseOperations()
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self.client = DatabaseClient()
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self.creation = DatabaseCreation(self)
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self.introspection = DatabaseIntrospection(self)
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self.validation = BaseDatabaseValidation()
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def _valid_connection(self):
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return self.connection is not None
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def _cursor(self, settings):
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cursor = None
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if not self._valid_connection():
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if len(settings.DATABASE_HOST.strip()) == 0:
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settings.DATABASE_HOST = 'localhost'
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if len(settings.DATABASE_PORT.strip()) != 0:
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dsn = Database.makedsn(settings.DATABASE_HOST, int(settings.DATABASE_PORT), settings.DATABASE_NAME)
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self.connection = Database.connect(settings.DATABASE_USER, settings.DATABASE_PASSWORD, dsn, **self.options)
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else:
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conn_string = "%s/%s@%s" % (settings.DATABASE_USER, settings.DATABASE_PASSWORD, settings.DATABASE_NAME)
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self.connection = Database.connect(conn_string, **self.options)
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cursor = FormatStylePlaceholderCursor(self.connection)
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# Set oracle date to ansi date format. This only needs to execute
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# once when we create a new connection.
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cursor.execute("ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD' "
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"NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF'")
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try:
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self.oracle_version = int(self.connection.version.split('.')[0])
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# There's no way for the DatabaseOperations class to know the
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# currently active Oracle version, so we do some setups here.
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# TODO: Multi-db support will need a better solution (a way to
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# communicate the current version).
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if self.oracle_version <= 9:
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self.ops.regex_lookup = self.ops.regex_lookup_9
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else:
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self.ops.regex_lookup = self.ops.regex_lookup_10
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except ValueError:
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pass
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try:
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self.connection.stmtcachesize = 20
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except:
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# Django docs specify cx_Oracle version 4.3.1 or higher, but
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# stmtcachesize is available only in 4.3.2 and up.
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pass
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if not cursor:
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cursor = FormatStylePlaceholderCursor(self.connection)
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# Default arraysize of 1 is highly sub-optimal.
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cursor.arraysize = 100
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return cursor
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class OracleParam(object):
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"""
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Wrapper object for formatting parameters for Oracle. If the string
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representation of the value is large enough (greater than 4000 characters)
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the input size needs to be set as NCLOB. Alternatively, if the parameter has
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an `input_size` attribute, then the value of the `input_size` attribute will
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be used instead. Otherwise, no input size will be set for the parameter when
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executing the query.
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"""
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def __init__(self, param, charset, strings_only=False):
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self.smart_str = smart_str(param, charset, strings_only)
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if hasattr(param, 'input_size'):
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# If parameter has `input_size` attribute, use that.
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self.input_size = param.input_size
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elif isinstance(param, basestring) and len(param) > 4000:
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# Mark any string parameter greater than 4000 characters as an NCLOB.
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self.input_size = Database.NCLOB
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else:
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self.input_size = None
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class FormatStylePlaceholderCursor(Database.Cursor):
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"""
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Django uses "format" (e.g. '%s') style placeholders, but Oracle uses ":var"
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style. This fixes it -- but note that if you want to use a literal "%s" in
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a query, you'll need to use "%%s".
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We also do automatic conversion between Unicode on the Python side and
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UTF-8 -- for talking to Oracle -- in here.
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"""
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charset = 'utf-8'
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def _format_params(self, params):
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if isinstance(params, dict):
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result = {}
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for key, value in params.items():
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result[smart_str(key, self.charset)] = OracleParam(param, self.charset)
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return result
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else:
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return tuple([OracleParam(p, self.charset, True) for p in params])
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def _guess_input_sizes(self, params_list):
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if isinstance(params_list[0], dict):
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sizes = {}
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iterators = [params.iteritems() for params in params_list]
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else:
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sizes = [None] * len(params_list[0])
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iterators = [enumerate(params) for params in params_list]
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for iterator in iterators:
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for key, value in iterator:
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if value.input_size: sizes[key] = value.input_size
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if isinstance(sizes, dict):
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self.setinputsizes(**sizes)
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else:
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self.setinputsizes(*sizes)
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def _param_generator(self, params):
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if isinstance(params, dict):
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return dict([(k, p.smart_str) for k, p in params.iteritems()])
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else:
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return [p.smart_str for p in params]
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def execute(self, query, params=None):
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if params is None:
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params = []
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else:
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params = self._format_params(params)
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args = [(':arg%d' % i) for i in range(len(params))]
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# cx_Oracle wants no trailing ';' for SQL statements. For PL/SQL, it
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# it does want a trailing ';' but not a trailing '/'. However, these
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# characters must be included in the original query in case the query
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# is being passed to SQL*Plus.
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if query.endswith(';') or query.endswith('/'):
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query = query[:-1]
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query = smart_str(query, self.charset) % tuple(args)
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self._guess_input_sizes([params])
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return Database.Cursor.execute(self, query, self._param_generator(params))
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def executemany(self, query, params=None):
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try:
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args = [(':arg%d' % i) for i in range(len(params[0]))]
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except (IndexError, TypeError):
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# No params given, nothing to do
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return None
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# cx_Oracle wants no trailing ';' for SQL statements. For PL/SQL, it
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# it does want a trailing ';' but not a trailing '/'. However, these
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# characters must be included in the original query in case the query
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# is being passed to SQL*Plus.
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if query.endswith(';') or query.endswith('/'):
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query = query[:-1]
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query = smart_str(query, self.charset) % tuple(args)
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formatted = [self._format_params(i) for i in params]
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self._guess_input_sizes(formatted)
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return Database.Cursor.executemany(self, query, [self._param_generator(p) for p in formatted])
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def fetchone(self):
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row = Database.Cursor.fetchone(self)
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if row is None:
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return row
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return tuple([to_unicode(e) for e in row])
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def fetchmany(self, size=None):
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if size is None:
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size = self.arraysize
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return tuple([tuple([to_unicode(e) for e in r]) for r in Database.Cursor.fetchmany(self, size)])
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def fetchall(self):
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return tuple([tuple([to_unicode(e) for e in r]) for r in Database.Cursor.fetchall(self)])
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def to_unicode(s):
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"""
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Convert strings to Unicode objects (and return all other data types
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unchanged).
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"""
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if isinstance(s, basestring):
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return force_unicode(s)
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return s
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def _get_sequence_reset_sql():
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# TODO: colorize this SQL code with style.SQL_KEYWORD(), etc.
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return """
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DECLARE
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startvalue integer;
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cval integer;
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BEGIN
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LOCK TABLE %(table)s IN SHARE MODE;
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SELECT NVL(MAX(%(column)s), 0) INTO startvalue FROM %(table)s;
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SELECT %(sequence)s.nextval INTO cval FROM dual;
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cval := startvalue - cval;
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IF cval != 0 THEN
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EXECUTE IMMEDIATE 'ALTER SEQUENCE %(sequence)s MINVALUE 0 INCREMENT BY '||cval;
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SELECT %(sequence)s.nextval INTO cval FROM dual;
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EXECUTE IMMEDIATE 'ALTER SEQUENCE %(sequence)s INCREMENT BY 1';
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END IF;
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COMMIT;
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END;
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/"""
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def get_sequence_name(table):
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name_length = DatabaseOperations().max_name_length() - 3
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return '%s_SQ' % util.truncate_name(table, name_length).upper()
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def get_trigger_name(table):
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name_length = DatabaseOperations().max_name_length() - 3
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return '%s_TR' % util.truncate_name(table, name_length).upper()
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