Class Table

pattern/db/__init__.py:801–1004

    pass

class Table(object):
    
    class Fields(list):
        # Table.fields.append() alters the table.
        # New field() with optional=False must have a default value (can not be NOW).
        # New field() can have index=True, but not PRIMARY or UNIQUE. 
        def __init__(self, table, *args, **kwargs):
            list.__init__(self, *args, **kwargs); self.table=table
        def append(self, field):
            name, (field, index) = field[0], self.table.db._field_SQL(self.table.name, field)
            self.table.db.execute("alter table `%s` add column %s;" % (self.table.name, field))
            self.table.db.execute(index, commit=True)
            self.table._update()
        def extend(self, fields):
            [self.append(f) for f in fields]
        def __setitem__(self, *args, **kwargs):
            raise NotImplementedError, "Table.fields only supports append()"
        insert = remove = pop = __setitem__
    
    def __init__(self, name, database):
        """ A collection of rows consisting of one or more fields (i.e., table columns) 
            of a certain type (i.e., strings, numbers).
        """
        self.database    = database
        self._name       = name
        self.fields      = [] # List of field names (i.e., column names).
        self.schema      = {} # Dictionary of (field, Schema)-items.
        self.default     = {} # Default values for Table.insert().
        self.primary_key = None
        self._update()
    
    def _update(self):
        # Retrieve table column names.
        # Table column names are available in the Table.fields list.
        # Table column names should not contain unicode because they can also be function parameters.
        # Table column names should avoid " ", ".", "(" and ")".
        # The primary key column is stored in Table.primary_key.
        self.fields = Table.Fields(self)
        if self.name not in self.database.tables:
            raise TableError, "table '%s' does not exist" % (self.database.name + "." + self.name)
        if self.db.type == MYSQL:
            q = "show columns from `%s`;" % self.name
        if self.db.type == SQLITE:
            q = "pragma table_info(`%s`);" % self.name
            i = self.db.execute("pragma index_list(`%s`)" % self.name) # look up indices
            i = dict(((v[1].replace(self.name+"_", "", 1), v[2]) for v in i))
        for f in self.db.execute(q):
            # [name, type, default, index, optional, extra]
            if self.db.type == MYSQL:
                f = [f[0], f[1], f[4], f[3], f[2], f[5]] 
            if self.db.type == SQLITE:
                f = [f[1], f[2], f[4], f[5], f[3], ""]
                f[3] = f[3] == 1 and "pri" or (f[0] in i and ("1","uni")[int(i[f[0]])] or "")
            list.append(self.fields, f[0])
            self.schema[f[0]] = Schema(*f)
            if self.schema[f[0]].index == PRIMARY:
                self.primary_key = f[0]