def rewrite(self, sql):
try:
# silently fail index creation; indexes are passe
if sql.startswith("CREATE INDEX"):
return None
self.parser = SqlParser()
analysis = self.parser.parse(sql)
if isinstance(analysis, InsertRow):
return self.rewrite_INSERT(analysis)
if isinstance(analysis, UpdateAnalysis):
return self.rewrite_UPDATE(analysis)
if isinstance(analysis, DeleteAnalysis):
return self.rewrite_DELETE(analysis)
if isinstance(analysis, SelectAnalysis):
return self.rewrite_SELECT(analysis)
if isinstance(analysis, TableSchema):
return self.rewrite_CREATE_TABLE(analysis)
except ParseException, err:
raise SqlSyntaxError(err.message, line=err.line)
class rewriter:
"""Rewrites SQL queries as SPARQL queries, using the dbns base uri for anything not explicitly aliased
>>> sql = rewriter("urn:ponga:example/")
>>> print sql.pk_uri("Story", 1)
urn:ponga:example/story/1/
"""
def __init__(self, dbns_uri, schema={}):
self.base_uri = dbns_uri
self.schema = schema
def table_uri(self, table_name):
"""
Convert a table name to a URI that represents that table.
Tables that are not otherwise aliased become:
BASE_URI/table
>>> sql = rewriter("urn:ponga:example/")
>>> print sql.table_uri("Story")
urn:ponga:example/story
"""
return self.base_uri + table_name.lower()
def column_uri(self, table_name, column_name):
"""
Convert a table and column name to a URI that represents that column.
Columns that are not otherwise aliased become:
BASE_URI/table.column
>>> sql = rewriter("urn:ponga:example/")
>>> print sql.column_uri("Story", "title")
urn:ponga:example/story.title
"""
return self.table_uri(table_name) + "." + column_name.lower()
def pk_uri(self, table_name, pk_id):
"""
Given a table and simple PK, work out the URI
BASE_URI/table/id/
"""
return "%s/%s/" % (self.table_uri(table_name), pk_id)
def rewrite(self, sql):
try:
# silently fail index creation; indexes are passe
if sql.startswith("CREATE INDEX"):
return None
self.parser = SqlParser()
analysis = self.parser.parse(sql)
if isinstance(analysis, InsertRow):
return self.rewrite_INSERT(analysis)
if isinstance(analysis, UpdateAnalysis):
return self.rewrite_UPDATE(analysis)
if isinstance(analysis, DeleteAnalysis):
return self.rewrite_DELETE(analysis)
if isinstance(analysis, SelectAnalysis):
return self.rewrite_SELECT(analysis)
if isinstance(analysis, TableSchema):
return self.rewrite_CREATE_TABLE(analysis)
except ParseException, err:
raise SqlSyntaxError(err.message, line=err.line)
except Exception:
print "-" * 20
print sql
print "-" * 20
raise
