self.version = version
self.tables = tables
- # Validate that all ref_tables refer to the names of tables
- # that exist.
- for table in self.tables.itervalues():
- for column in table.columns.itervalues():
- self.__check_ref_table(column, column.type.key, "key")
- self.__check_ref_table(column, column.type.value, "value")
-
# "isRoot" was not part of the original schema definition. Before it
# was added, there was no support for garbage collection. So, for
# backward compatibility, if the root set is empty then assume that
for table in self.tables.itervalues():
table.is_root = True
+ # Validate that all ref_tables refer to the names of tables
+ # that exist.
+ #
+ # Also force certain columns to be persistent, as explained in
+ # __check_ref_table(). This requires 'is_root' to be known, so this
+ # must follow the loop updating 'is_root' above.
+ for table in self.tables.itervalues():
+ for column in table.columns.itervalues():
+ self.__check_ref_table(column, column.type.key, "key")
+ self.__check_ref_table(column, column.type.value, "value")
+
def __root_set_size(self):
"""Returns the number of tables in the schema's root set."""
n_root = 0
return json
def __check_ref_table(self, column, base, base_name):
- if (base and base.type == types.UuidType and base.ref_table and
- base.ref_table not in self.tables):
+ if not base or base.type != types.UuidType or not base.ref_table:
+ return
+
+ ref_table = self.tables.get(base.ref_table)
+ if not ref_table:
raise error.Error("column %s %s refers to undefined table %s"
% (column.name, base_name, base.ref_table),
tag="syntax error")
+ if base.is_strong_ref() and not ref_table.is_root:
+ # We cannot allow a strong reference to a non-root table to be
+ # ephemeral: if it is the only reference to a row, then replaying
+ # the database log from disk will cause the referenced row to be
+ # deleted, even though it did exist in memory. If there are
+ # references to that row later in the log (to modify it, to delete
+ # it, or just to point to it), then this will yield a transaction
+ # error.
+ column.persistent = True
+
class IdlSchema(DbSchema):
def __init__(self, name, version, tables, idlPrefix, idlHeader):
DbSchema.__init__(self, name, version, tables)
return IdlSchema(schema.name, schema.version, schema.tables,
idlPrefix, idlHeader)
+def column_set_from_json(json, columns):
+ if json is None:
+ return tuple(columns)
+ elif type(json) != list:
+ raise error.Error("array of distinct column names expected", json)
+ else:
+ for column_name in json:
+ if type(column_name) not in [str, unicode]:
+ raise error.Error("array of distinct column names expected",
+ json)
+ elif column_name not in columns:
+ raise error.Error("%s is not a valid column name"
+ % column_name, json)
+ if len(set(json)) != len(json):
+ # Duplicate.
+ raise error.Error("array of distinct column names expected", json)
+ return tuple([columns[column_name] for column_name in json])
+
class TableSchema(object):
def __init__(self, name, columns, mutable=True, max_rows=sys.maxint,
- is_root=True):
+ is_root=True, indexes=[]):
self.name = name
self.columns = columns
self.mutable = mutable
self.max_rows = max_rows
self.is_root = is_root
+ self.indexes = indexes
@staticmethod
def from_json(json, name):
parser = ovs.db.parser.Parser(json, "table schema for table %s" % name)
- columnsJson = parser.get("columns", [dict])
+ columns_json = parser.get("columns", [dict])
mutable = parser.get_optional("mutable", [bool], True)
max_rows = parser.get_optional("maxRows", [int])
is_root = parser.get_optional("isRoot", [bool], False)
+ indexes_json = parser.get_optional("indexes", [list], [])
parser.finish()
if max_rows == None:
elif max_rows <= 0:
raise error.Error("maxRows must be at least 1", json)
- if not columnsJson:
+ if not columns_json:
raise error.Error("table must have at least one column", json)
columns = {}
- for columnName, columnJson in columnsJson.iteritems():
- if columnName.startswith('_'):
+ for column_name, column_json in columns_json.iteritems():
+ if column_name.startswith('_'):
raise error.Error("names beginning with \"_\" are reserved",
json)
- elif not ovs.db.parser.is_identifier(columnName):
+ elif not ovs.db.parser.is_identifier(column_name):
raise error.Error("name must be a valid id", json)
- columns[columnName] = ColumnSchema.from_json(columnJson,
- columnName)
-
- return TableSchema(name, columns, mutable, max_rows, is_root)
+ columns[column_name] = ColumnSchema.from_json(column_json,
+ column_name)
+
+ indexes = []
+ for index_json in indexes_json:
+ index = column_set_from_json(index_json, columns)
+ if not index:
+ raise error.Error("index must have at least one column", json)
+ elif len(index) == 1:
+ index[0].unique = True
+ for column in index:
+ if not column.persistent:
+ raise error.Error("ephemeral columns (such as %s) may "
+ "not be indexed" % column.name, json)
+ indexes.append(index)
+
+ return TableSchema(name, columns, mutable, max_rows, is_root, indexes)
def to_json(self, default_is_root=False):
"""Returns this table schema serialized into JSON.
if self.max_rows != sys.maxint:
json["maxRows"] = self.max_rows
+ if self.indexes:
+ json["indexes"] = []
+ for index in self.indexes:
+ json["indexes"].append([column.name for column in index])
+
return json
class ColumnSchema(object):
self.mutable = mutable
self.persistent = persistent
self.type = type
+ self.unique = False
@staticmethod
def from_json(json, name):