def test_simple_query_merge():
book_id = SQLQuery(
["users", "books"], "books.id", {"users.id": 1, "books.user_id": sql_query_dict.mysql_col("user.id")}
)
combined = SQLQuery(["books"], "books.name", {"books.id": book_id})
combined.flatten()
assert combined == SQLQuery(
"users, books", "books.name", {"users.id": 1, "books.user_id": sql_query_dict.mysql_col("user.id")}
)
def flatten(self):
""" merge any SQLQuery objects on the rhs of a where clause
into self. """
self._assert_flattenable()
for k, v in self.where.copy().items():
if isinstance(v, SQLQuery):
v._assert_flattenable()
self.tables.update(v.tables)
self._assert_no_overlapping_where(v.where)
self.where.update(v.where)
if len(v.selects) != 1:
raise ValueError((
'SQLQuery merging is only possible when '
'the embedded query has one select. has: {}'
).format(', '.join(v.selects)))
self.where[k] = sql_query_dict.mysql_col(v.selects[0])
# we just did a join, so definitely not just the first
self.first = False
self.cleanup()
def test_simple_query_merge():
book_id = SQLQuery(['users', 'books'], 'books.id', {
'users.id': 1,
'books.user_id': sql_query_dict.mysql_col('user.id'),
})
combined = SQLQuery(['books'], 'books.name', {
'books.id': book_id
})
combined.flatten()
assert combined == SQLQuery(
'users, books', 'books.name', {
'users.id': 1,
'books.user_id': sql_query_dict.mysql_col('user.id'),
})
def merge_parent_child(child, parent):
""" NOTE: child and parent are switched here, it makes more sense """
parent.function._assert_flattenable()
child.function._assert_flattenable()
function = parent.function.copy()
for k, v in function.input_mapping.items():
child_function = child.function.copy()
# simply merge these parts of the SQLQuery
function.tables.update(child_function.tables)
function.where.update(child_function.where)
function.selects.extend(child_function.selects)
# join where clause and selects
# the connecting path is the path which is set by the child and
# read by the parent
connecting_path = parent.input_path_by_property(k)
# lookup the order that this path occurrs in the outputs so we can
# match it up with the correct select
i = child.outgoing_paths.index(connecting_path)
# join in the where clause
function.where[v] = sql_query_dict.mysql_col(
child_function.selects[i]
)
# remove unnecessary complexity
function.cleanup()
# TODO: assumes that all inputs were from SQLQuery objects
function.input_mapping = child.function.input_mapping
# even if there is just one column, this also works so long as
# Cardinality.many
function.one_column = False
function.first = False
inputs = child.incoming_paths
outputs = parent.outgoing_paths + child.outgoing_paths
relations = parent.relations + child.relations
return Node(
None, inputs, outputs, function, Cardinality.many, relations
)