You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
89 lines
2.8 KiB
89 lines
2.8 KiB
3 years ago
|
class ColRef:
|
||
|
|
def __init__(self, _ty, cobj, table:'TableInfo', name, id, compound = False):
|
||
|
|
self.type = _ty
|
||
|
|
self.cobj = cobj
|
||
|
|
self.table = table
|
||
|
|
self.name = name
|
||
|
|
self.alias = set()
|
||
|
|
self.id = id # position in table
|
||
|
|
self.compound = compound # compound field (list as a field)
|
||
|
|
# e.g. order by, group by, filter by expressions
|
||
|
|
|
||
|
|
self.__arr__ = (_ty, cobj, table, name, id)
|
||
|
|
def __getitem__(self, key):
|
||
|
|
if type(key) is str:
|
||
|
|
return getattr(self, key)
|
||
|
|
else:
|
||
|
|
return self.__arr__[key]
|
||
|
|
|
||
|
|
def __setitem__(self, key, value):
|
||
|
|
self.__arr__[key] = value
|
||
|
|
|
||
|
|
|
||
|
|
class TableInfo:
|
||
|
|
def __init__(self, table_name, cols, cxt:'Context'):
|
||
|
|
# statics
|
||
|
|
self.table_name = table_name
|
||
|
|
self.alias = set([table_name])
|
||
|
|
self.columns_byname = dict() # column_name, type
|
||
|
|
self.columns = []
|
||
|
|
self.cxt = cxt
|
||
|
|
# keep track of temp vars
|
||
|
|
self.rec = None
|
||
|
|
self.add_cols(cols)
|
||
|
|
# runtime
|
||
|
|
self.order = [] # assumptions
|
||
|
|
|
||
|
|
cxt.tables_byname[self.table_name] = self # construct reverse map
|
||
|
|
|
||
|
|
def add_cols(self, cols, new = True):
|
||
|
|
for i, c in enumerate(cols):
|
||
|
|
self.add_col(c, new, i)
|
||
|
|
def add_col(self, c, new = True, i = 0):
|
||
|
|
_ty = c['type']
|
||
|
|
if new:
|
||
|
|
_ty = _ty if type(c) is ColRef else list(_ty.keys())[0]
|
||
|
|
col_object = ColRef(_ty, c, self, c['name'], len(self.columns))
|
||
|
|
else:
|
||
|
|
col_object = c
|
||
|
|
c.table = self
|
||
|
|
self.columns_byname[c['name']] = col_object
|
||
|
|
self.columns.append(col_object)
|
||
|
|
|
||
|
|
def add_alias(self, alias):
|
||
|
|
if alias in self.cxt.tables_byname.keys():
|
||
|
|
print("Error: table alias already exists")
|
||
|
|
return
|
||
|
|
self.cxt.tables_byname[alias] = self
|
||
|
|
self.alias.add(alias)
|
||
|
|
def parse_col_names(self, colExpr) -> ColRef:
|
||
|
|
parsedColExpr = colExpr.split('.')
|
||
|
|
if len(parsedColExpr) <= 1:
|
||
|
|
return self.columns_byname[colExpr]
|
||
|
|
else:
|
||
|
|
datasource = self.cxt.tables_byname[parsedColExpr[0]]
|
||
|
|
if datasource is None:
|
||
|
|
raise ValueError(f'Table name/alias not defined{parsedColExpr[0]}')
|
||
|
|
else:
|
||
|
|
return datasource.parse_col_names(parsedColExpr[1])
|
||
|
|
|
||
|
|
|
||
|
|
class Context:
|
||
|
|
def __init__(self):
|
||
|
|
self.sql = ''
|
||
|
|
self.tables_byname = dict()
|
||
|
|
self.col_byname = dict()
|
||
|
|
self.tables = []
|
||
|
|
self.cols = []
|
||
|
|
self.datasource = None
|
||
|
|
self.udf_map = dict()
|
||
|
|
|
||
|
|
def emit(self, sql:str):
|
||
|
|
self.sql += sql + ' '
|
||
|
|
|
||
|
|
def add_table(self, table_name, cols):
|
||
|
|
tbl = TableInfo(table_name, cols, self)
|
||
|
|
self.tables.append(tbl)
|
||
|
|
return tbl
|
||
|
|
|
||
|
|
|