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"""
Neo4j DB object
"""
from enum import Enum
from neo4j_cypher_parser import Cypher_Parser, e_clause__where, e_keyword,\
e_value
import logging
import neo4j_cypher_parser
import neo4j_schema
log = logging.getLogger('rhizi')
class Query_Struct_Type(Enum):
unkown = 1
r = 2
w = 3
rw = 4
def __add__(self, other):
if self == other or self == Query_Struct_Type.rw:
return self
if self == Query_Struct_Type.unkown:
return other
if self == Query_Struct_Type.r and other != Query_Struct_Type.r:
return Query_Struct_Type.rw
if self == Query_Struct_Type.w and other != Query_Struct_Type.w:
return Query_Struct_Type.rw
def __str__(self):
if self == Query_Struct_Type.unkown: return 'unkown'
if self == Query_Struct_Type.r: return 'r'
if self == Query_Struct_Type.w: return 'w'
if self == Query_Struct_Type.rw: return 'rw'
assert False
def __eq__(self, other): # allow comparing against r/w/rw strings
if other in ['r', 'w', 'rw']:
if self == Query_Struct_Type.r and other == 'r': return True
if self == Query_Struct_Type.w and other == 'w': return True
if self == Query_Struct_Type.rw and other == 'rw': return True
if not isinstance(other, Query_Struct_Type): return False
return super(Query_Struct_Type, self).__eq__(other)
class DB_Query(object):
def __init__(self, q_arr, param_set={}):
"""
@param q_str_or_array: cypher query to add - if passed as an array ' '.join(q_str_or_array)
is used to convert it to string type
"""
assert type(q_arr) is list
# establish query type
self.q_str = ' '.join(q_arr) # FIXME: rm
self.pt_root = Cypher_Parser().parse_expression(self.q_str)
self.param_set = param_set
def __str__(self):
return self.pt_root.str__cypher_query()
def __repr__(self):
return 'q: %s, params: %s\n%s' % (self.pt_root.str__cypher_query(),
self.param_set,
self.pt_root.str__struct_tree())
def __iter__(self):
for keyword, clause_set in self.pt_root.index__kw_to_clause_set().items():
yield keyword, clause_set
def t__add_node_filter__meta_label(self):
if Query_Struct_Type.w == self.query_struct_type:
return
meta_label_cond = '0 = length(filter(_lbl in labels(n) where _lbl in {meta_label_set}))' # filter nodes with meta labels
c_set__where = self.pt_root.clause_set_by_kw('where')
if not c_set__where:
c_set__match = self.pt_root.clause_set_by_kw('match')
first_match_clause = c_set__match.pop()
wc = first_match_clause.spawn_sibling__adjacent(e_clause__where)
wc.spawn_child(e_keyword, 'where')
wc.spawn_child(e_value).value = meta_label_cond
else: # where clause present
assert len(c_set__where) == 1, 't__add_node_filter__meta_label: no support for multi-where clauses query transformation'
wc = c_set__where[0]
wc_cond = wc.condition_value
wc.set_condition(meta_label_cond + ' and ' + wc_cond)
self.param_set['meta_label_set'] = neo4j_schema.meta_label_set
@property
def query_struct_type(self):
"""
calc query_structure_type: read|write|read-write
"""
r = False
w = False
for kw, _clause_set in self.pt_root.index__kw_to_clause_set().items():
if kw in neo4j_cypher_parser.tok_set__kw__write:
w = True
if kw == 'match':
r = True
if r and w: return Query_Struct_Type.rw
if r and not w: return Query_Struct_Type.r
if w and not r: return Query_Struct_Type.w
return Query_Struct_Type.unkown
def str__cypher_query(self):
return self.pt_root.str__cypher_query()
class DB_row(object):
def __init__(self, data):
self.data = data
def __iter__(self):
for column_val in self.data:
yield column_val
def items(self):
return [x for x in self]
def __str__(self):
return str(self.items())
def __repr__(self):
return repr(self.items())
class DB_result_set(object):
def __init__(self, data):
self.data = data
def __iter__(self):
for db_row_dict in self.data['data']:
# example: dict: {u'row': [{u'title': u'foo'}]}
assert None != db_row_dict['row']
yield DB_row(db_row_dict['row'])
def items(self):
return [x for x in self]
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