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[boulder-oracle-sprint] Refactoring to move some oracle conditional code
into the backend git-svn-id: http://code.djangoproject.com/svn/django/branches/boulder-oracle-sprint@4021 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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Boulder Sprinters
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@ -1,6 +1,6 @@
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# NOTE: still dependent on other code that Matt Boersma is working on, not yet tested!!! - Jim Baker
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from django.db import backend, connection
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from django.db.models.query import handle_legacy_orderlist
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from django.utils.datastructures import SortedDict
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import cx_Oracle as Database
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@ -17,14 +17,14 @@ def get_query_set_class(DefaultQuerySet):
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# undefined, so we convert it to a list of tuples.
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extra_select = self._select.items()
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cursor = connection.cursor()
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full_query = None
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select, sql, params, full_query = self._get_sql_clause()
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if not full_query:
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cursor.execute("SELECT " + (self._distinct and "DISTINCT " or "") + ",".join(select) + sql, params)
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else:
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full_query = "SELECT %s%s\n%s" % \
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((self._distinct and "DISTINCT " or ""),
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', '.join(select), sql)
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cursor = connection.cursor()
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cursor.execute(full_query, params)
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fill_cache = self._select_related
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@ -51,5 +51,111 @@ def get_query_set_class(DefaultQuerySet):
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setattr(obj, k[0], row[index_end+i])
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yield obj
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def _get_sql_clause(self):
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opts = self.model._meta
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# Construct the fundamental parts of the query: SELECT X FROM Y WHERE Z.
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select = ["%s.%s" % (backend.quote_name(opts.db_table), backend.quote_name(f.column)) for f in opts.fields]
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tables = [quote_only_if_word(t) for t in self._tables]
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joins = SortedDict()
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where = self._where[:]
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params = self._params[:]
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# Convert self._filters into SQL.
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joins2, where2, params2 = self._filters.get_sql(opts)
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joins.update(joins2)
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where.extend(where2)
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params.extend(params2)
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# Add additional tables and WHERE clauses based on select_related.
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if self._select_related:
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fill_table_cache(opts, select, tables, where, opts.db_table, [opts.db_table])
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# Add any additional SELECTs.
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if self._select:
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select.extend(['(%s) AS %s' % (quote_only_if_word(s[1]), backend.quote_name(s[0])) for s in self._select.items()])
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# Start composing the body of the SQL statement.
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sql = [" FROM", backend.quote_name(opts.db_table)]
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# Compose the join dictionary into SQL describing the joins.
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if joins:
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sql.append(" ".join(["%s %s %s ON %s" % (join_type, table, alias, condition)
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for (alias, (table, join_type, condition)) in joins.items()]))
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# Compose the tables clause into SQL.
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if tables:
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sql.append(", " + ", ".join(tables))
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# Compose the where clause into SQL.
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if where:
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sql.append(where and "WHERE " + " AND ".join(where))
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# ORDER BY clause
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order_by = []
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if self._order_by is not None:
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ordering_to_use = self._order_by
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else:
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ordering_to_use = opts.ordering
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for f in handle_legacy_orderlist(ordering_to_use):
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if f == '?': # Special case.
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order_by.append(backend.get_random_function_sql())
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else:
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if f.startswith('-'):
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col_name = f[1:]
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order = "DESC"
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else:
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col_name = f
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order = "ASC"
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if "." in col_name:
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table_prefix, col_name = col_name.split('.', 1)
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table_prefix = backend.quote_name(table_prefix) + '.'
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else:
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# Use the database table as a column prefix if it wasn't given,
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# and if the requested column isn't a custom SELECT.
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if "." not in col_name and col_name not in (self._select or ()):
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table_prefix = backend.quote_name(opts.db_table) + '.'
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else:
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table_prefix = ''
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order_by.append('%s%s %s' % (table_prefix, backend.quote_name(orderfield2column(col_name, opts)), order))
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if order_by:
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sql.append("ORDER BY " + ", ".join(order_by))
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# LIMIT and OFFSET clauses
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# To support limits and offsets, Oracle requires some funky rewriting of an otherwise normal looking query.
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select_clause = ",".join(select)
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distinct = (self._distinct and "DISTINCT " or "")
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if order_by:
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order_by_clause = " OVER (ORDER BY %s )" % (", ".join(order_by))
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else:
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#Oracle's row_number() function always requires an order-by clause.
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#So we need to define a default order-by, since none was provided.
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order_by_clause = " OVER (ORDER BY %s.%s)" % \
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(backend.quote_name(opts.db_table),
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backend.quote_name(opts.fields[0].db_column or opts.fields[0].column))
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# limit_and_offset_clause
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offset = self._offset and int(self._offset) or 0
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limit = self._limit and int(self._limit) or None
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limit_and_offset_clause = ''
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if limit:
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limit_and_offset_clause = "WHERE rn > %s AND rn <= %s" % (offset, limit+offset)
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elif offset:
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limit_and_offset_clause = "WHERE rn > %s" % (offset)
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if len(limit_and_offset_clause) > 0:
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full_query = """SELECT * FROM
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(SELECT %s
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%s,
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ROW_NUMBER() %s AS rn
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%s
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)
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%s
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""" % (distinct, select_clause, order_by_clause, " ".join(sql), limit_and_offset_clause)
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else:
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full_query = None
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return select, " ".join(sql), params, full_query
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return OracleQuerySet
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@ -172,15 +172,9 @@ class _QuerySet(object):
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cursor = connection.cursor()
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full_query = None
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if settings.DATABASE_ENGINE == 'oracle':
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select, sql, params, full_query = self._get_sql_clause()
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else:
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select, sql, params = self._get_sql_clause()
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if not full_query:
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cursor.execute("SELECT " + (self._distinct and "DISTINCT " or "") + ",".join(select) + sql, params)
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else:
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cursor.execute(full_query, params)
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fill_cache = self._select_related
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index_end = len(self.model._meta.fields)
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while 1:
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@ -515,48 +509,12 @@ class _QuerySet(object):
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sql.append("ORDER BY " + ", ".join(order_by))
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# LIMIT and OFFSET clauses
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if settings.DATABASE_ENGINE != 'oracle':
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if self._limit is not None:
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sql.append("%s " % backend.get_limit_offset_sql(self._limit, self._offset))
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else:
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assert self._offset is None, "'offset' is not allowed without 'limit'"
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return select, " ".join(sql), params
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else:
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# To support limits and offsets, Oracle requires some funky rewriting of an otherwise normal looking query.
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select_clause = ",".join(select)
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distinct = (self._distinct and "DISTINCT " or "")
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if order_by:
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order_by_clause = " OVER (ORDER BY %s )" % (", ".join(order_by))
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else:
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#Oracle's row_number() function always requires an order-by clause.
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#So we need to define a default order-by, since none was provided.
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order_by_clause = " OVER (ORDER BY %s.%s)" % \
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(backend.quote_name(opts.db_table),
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backend.quote_name(opts.fields[0].db_column or opts.fields[0].column))
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# limit_and_offset_clause
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offset = self._offset and int(self._offset) or 0
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limit = self._limit and int(self._limit) or None
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limit_and_offset_clause = ''
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if limit:
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limit_and_offset_clause = "WHERE rn > %s AND rn <= %s" % (offset, limit+offset)
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elif offset:
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limit_and_offset_clause = "WHERE rn > %s" % (offset)
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if len(limit_and_offset_clause) > 0:
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full_query = """SELECT * FROM
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(SELECT %s
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%s,
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ROW_NUMBER() %s AS rn
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%s
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)
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%s
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""" % (distinct, select_clause, order_by_clause, " ".join(sql), limit_and_offset_clause)
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else:
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full_query = None
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return select, " ".join(sql), params, full_query
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# Check to see if the DB backend would like to define its own QuerySet class
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# and otherwise use the default.
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