1 from types import StringTypes
5 from PLC.Faults import *
6 from PLC.Parameter import Parameter
10 Representation of a row in a database table. To use, optionally
11 instantiate with a dict of values. Update as you would a
12 dict. Commit to the database with sync().
15 # Set this to the name of the table that stores the row.
18 # Set this to the name of the primary key of the table. It is
19 # assumed that the this key is a sequence if it is not set when
23 # Set this to the names of tables that reference this table's
27 # Set this to a dict of the valid fields of this object and their
28 # types. Not all fields (e.g., joined fields) may be updated via
32 def __init__(self, api, fields = {}):
33 dict.__init__(self, fields)
38 Validates values. Will validate a value with a custom function
39 if a function named 'validate_[key]' exists.
42 # Warn about mandatory fields
43 mandatory_fields = self.api.db.fields(self.table_name, notnull = True, hasdef = False)
44 for field in mandatory_fields:
45 if not self.has_key(field) or self[field] is None:
46 raise PLCInvalidArgument, field + " must be specified and cannot be unset in class %s"%self.__class__.__name__
48 # Validate values before committing
49 for key, value in self.iteritems():
50 if value is not None and hasattr(self, 'validate_' + key):
51 validate = getattr(self, 'validate_' + key)
52 self[key] = validate(value)
54 def validate_timestamp(self, timestamp, check_future = False):
56 Validates the specified GMT timestamp string (must be in
57 %Y-%m-%d %H:%M:%S format) or number (seconds since UNIX epoch,
58 i.e., 1970-01-01 00:00:00 GMT). If check_future is True,
59 raises an exception if timestamp is not in the future. Returns
60 a GMT timestamp string.
63 time_format = "%Y-%m-%d %H:%M:%S"
65 if isinstance(timestamp, StringTypes):
66 # calendar.timegm() is the inverse of time.gmtime()
67 timestamp = calendar.timegm(time.strptime(timestamp, time_format))
69 # Human readable timestamp string
70 human = time.strftime(time_format, time.gmtime(timestamp))
72 if check_future and timestamp < time.time():
73 raise PLCInvalidArgument, "'%s' not in the future" % human
77 def add_object(self, classobj, join_table, columns = None):
79 Returns a function that can be used to associate this object
83 def add(self, obj, columns = None, commit = True):
85 Associate with the specified object.
88 # Various sanity checks
89 assert isinstance(self, Row)
90 assert self.primary_key in self
91 assert join_table in self.join_tables
92 assert isinstance(obj, classobj)
93 assert isinstance(obj, Row)
94 assert obj.primary_key in obj
95 assert join_table in obj.join_tables
97 # By default, just insert the primary keys of each object
98 # into the join table.
100 columns = {self.primary_key: self[self.primary_key],
101 obj.primary_key: obj[obj.primary_key]}
104 for name, value in columns.iteritems():
105 params.append(self.api.db.param(name, value))
107 self.api.db.do("INSERT INTO %s (%s) VALUES(%s)" % \
108 (join_table, ", ".join(columns), ", ".join(params)),
116 add_object = classmethod(add_object)
118 def remove_object(self, classobj, join_table):
120 Returns a function that can be used to disassociate this
124 def remove(self, obj, commit = True):
126 Disassociate from the specified object.
129 assert isinstance(self, Row)
130 assert self.primary_key in self
131 assert join_table in self.join_tables
132 assert isinstance(obj, classobj)
133 assert isinstance(obj, Row)
134 assert obj.primary_key in obj
135 assert join_table in obj.join_tables
137 self_id = self[self.primary_key]
138 obj_id = obj[obj.primary_key]
140 self.api.db.do("DELETE FROM %s WHERE %s = %s AND %s = %s" % \
142 self.primary_key, self.api.db.param('self_id', self_id),
143 obj.primary_key, self.api.db.param('obj_id', obj_id)),
151 remove_object = classmethod(remove_object)
153 def db_fields(self, obj = None):
155 Return only those fields that can be set or updated directly
156 (i.e., those fields that are in the primary table (table_name)
157 for this object, and are not marked as a read-only Parameter.
163 db_fields = self.api.db.fields(self.table_name)
164 return dict(filter(lambda (key, value): \
165 key in db_fields and \
166 (key not in self.fields or \
167 not isinstance(self.fields[key], Parameter) or \
168 not self.fields[key].ro),
176 # Filter out fields that cannot be set or updated directly
177 # (and thus would not affect equality for the purposes of
178 # deciding if we should sync() or not).
180 y = self.db_fields(y)
181 return dict.__eq__(x, y)
183 def sync(self, commit = True, insert = None):
185 Flush changes back to the database.
188 # Validate all specified fields
191 # Filter out fields that cannot be set or updated directly
192 db_fields = self.db_fields()
194 # Parameterize for safety
195 keys = db_fields.keys()
196 values = [self.api.db.param(key, value) for (key, value) in db_fields.items()]
198 # If the primary key (usually an auto-incrementing serial
199 # identifier) has not been specified, or the primary key is the
200 # only field in the table, or insert has been forced.
201 if not self.has_key(self.primary_key) or \
202 keys == [self.primary_key] or \
205 sql = "INSERT INTO %s (%s) VALUES (%s)" % \
206 (self.table_name, ", ".join(keys), ", ".join(values))
208 # Update existing row
209 columns = ["%s = %s" % (key, value) for (key, value) in zip(keys, values)]
210 sql = "UPDATE %s SET " % self.table_name + \
211 ", ".join(columns) + \
214 self.api.db.param(self.primary_key, self[self.primary_key]))
216 self.api.db.do(sql, db_fields)
218 if not self.has_key(self.primary_key):
219 self[self.primary_key] = self.api.db.last_insert_id(self.table_name, self.primary_key)
224 def delete(self, commit = True):
226 Delete row from its primary table, and from any tables that
230 assert self.primary_key in self
232 for table in self.join_tables + [self.table_name]:
233 if isinstance(table, tuple):
237 key = self.primary_key
239 sql = "DELETE FROM %s WHERE %s = %s" % \
241 self.api.db.param(self.primary_key, self[self.primary_key]))
243 self.api.db.do(sql, self)
250 Representation of row(s) in a database table.
253 def __init__(self, api, classobj, columns = None):
255 self.classobj = classobj
259 columns = classobj.fields
261 columns = filter(lambda x: x in classobj.fields, columns)
263 raise PLCInvalidArgument, "No valid return fields specified"
265 self.columns = columns
267 def sync(self, commit = True):
269 Flush changes back to the database.
275 def selectall(self, sql, params = None):
277 Given a list of rows from the database, fill ourselves with
281 for row in self.api.db.selectall(sql, params):
282 obj = self.classobj(self.api, row)
285 def dict(self, key_field = None):
287 Return ourself as a dict keyed on key_field.
290 if key_field is None:
291 key_field = self.classobj.primary_key
293 return dict([(obj[key_field], obj) for obj in self])