django1/django/db/backends/oracle/compiler.py

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from django.db.models.sql import compiler
class SQLCompiler(compiler.SQLCompiler):
def as_sql(self, with_limits=True, with_col_aliases=False, subquery=False):
"""
Creates the SQL for this query. Returns the SQL string and list
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of parameters. This is overridden from the original Query class
to handle the additional SQL Oracle requires to emulate LIMIT
and OFFSET.
If 'with_limits' is False, any limit/offset information is not
included in the query.
"""
# The `do_offset` flag indicates whether we need to construct
# the SQL needed to use limit/offset with Oracle.
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do_offset = with_limits and (self.query.high_mark is not None or self.query.low_mark)
if not do_offset:
sql, params = super(SQLCompiler, self).as_sql(
with_limits=False,
with_col_aliases=with_col_aliases,
subquery=subquery,
)
else:
sql, params = super(SQLCompiler, self).as_sql(
with_limits=False,
with_col_aliases=True,
subquery=subquery,
)
# Wrap the base query in an outer SELECT * with boundaries on
# the "_RN" column. This is the canonical way to emulate LIMIT
# and OFFSET on Oracle.
high_where = ''
if self.query.high_mark is not None:
high_where = 'WHERE ROWNUM <= %d' % (self.query.high_mark,)
sql = (
'SELECT * FROM (SELECT "_SUB".*, ROWNUM AS "_RN" FROM (%s) '
'"_SUB" %s) WHERE "_RN" > %d' % (sql, high_where, self.query.low_mark)
)
return sql, params
class SQLInsertCompiler(compiler.SQLInsertCompiler, SQLCompiler):
pass
class SQLDeleteCompiler(compiler.SQLDeleteCompiler, SQLCompiler):
pass
class SQLUpdateCompiler(compiler.SQLUpdateCompiler, SQLCompiler):
pass
class SQLAggregateCompiler(compiler.SQLAggregateCompiler, SQLCompiler):
pass