- Renamed (changed Remove to Delete)

[plcapi.git] / PLC / Table.py

diff --git a/PLC/Table.py b/PLC/Table.py
index ddc5f88..1300cf1 100644 (file)
--- a/PLC/Table.py
+++ b/PLC/Table.py
@@ -1,3 +1,6 @@
+from PLC.Faults import *
+from PLC.Parameter import Parameter
+
 class Row(dict):
     """
     Representation of a row in a database table. To use, optionally
@@ -5,6 +8,14 @@ class Row(dict):
     dict. Commit to the database with sync().
     """
 
+    # Set this to the name of the table that stores the row.
+    table_name = None
+
+    # Set this to the name of the primary key of the table. It is
+    # assumed that the this key is a sequence if it is not set when
+    # sync() is called.
+    primary_key = None
+
     # Set this to a dict of the valid fields of this object. Not all
     # fields (e.g., joined fields) may be updated via sync().
     fields = {}
@@ -15,8 +26,13 @@ class Row(dict):
         if a function named 'validate_[key]' exists.
         """
 
+        # Warn about mandatory fields
+        mandatory_fields = self.api.db.fields(self.table_name, notnull = True, hasdef = False)
+        for field in mandatory_fields:
+            if not self.has_key(field) or self[field] is None:
+                raise PLCInvalidArgument, field + " must be specified and cannot be unset"
+
         # Validate values before committing
-        # XXX Also truncate strings that are too long
         for key, value in self.iteritems():
             if value is not None and hasattr(self, 'validate_' + key):
                 validate = getattr(self, 'validate_' + key)
@@ -27,7 +43,59 @@ class Row(dict):
         Flush changes back to the database.
         """
 
-        pass
+        # Validate all specified fields
+        self.validate()
+
+        # Filter out fields that cannot be set or updated directly
+        all_fields = self.api.db.fields(self.table_name)
+        fields = dict(filter(lambda (key, value): \
+                             key in all_fields and \
+                             (key not in self.fields or \
+                              not isinstance(self.fields[key], Parameter) or \
+                              not self.fields[key].ro),
+                             self.items()))
+
+        # Parameterize for safety
+        keys = fields.keys()
+        values = [self.api.db.param(key, value) for (key, value) in fields.items()]
+
+        if not self.has_key(self.primary_key):
+            # Insert new row
+            sql = "INSERT INTO %s (%s) VALUES (%s);" % \
+                  (self.table_name, ", ".join(keys), ", ".join(values))
+        else:
+            # Update existing row
+            columns = ["%s = %s" % (key, value) for (key, value) in zip(keys, values)]
+            sql = "UPDATE %s SET " % self.table_name + \
+                  ", ".join(columns) + \
+                  " WHERE %s = %s" % \
+                  (self.primary_key,
+                   self.api.db.param(self.primary_key, self[self.primary_key]))
+
+        self.api.db.do(sql, fields)
+
+        if not self.has_key(self.primary_key):
+            self[self.primary_key] = self.api.db.last_insert_id(self.table_name, self.primary_key)
+
+        if commit:
+            self.api.db.commit()
+
+    def delete(self, commit = True):
+        """
+        Delete row from its primary table.
+        """
+
+        assert self.primary_key in self
+
+        sql = "DELETE FROM %s" % self.table_name + \
+              " WHERE %s = %s" % \
+              (self.primary_key,
+               self.api.db.param(self.primary_key, self[self.primary_key]))
+
+        self.api.db.do(sql, self)
+
+        if commit:
+            self.api.db.commit()
 
 class Table(dict):
     """