Python copy.update() Examples

def update(x, **entries):
    """Update a dict; or an object with slots; according to entries.
    >>> update({'a': 1}, a=10, b=20)
    {'a': 10, 'b': 20}
    >>> update(Struct(a=1), a=10, b=20)
    Struct(a=10, b=20)
    """
    if isinstance(x, dict):
        x.update(entries)   
    else:
        x.__dict__.update(entries) 
    return x 

#______________________________________________________________________________
# Functions on Sequences (mostly inspired by Common Lisp)
# NOTE: Sequence functions (count_if, find_if, every, some) take function
# argument first (like reduce, filter, and map). 

def test_date_functionality():
    "Tests different date operations that can be performed."
    # Create an orderz table to test the date type.
    orderz = Table(('OrderId', int), ('ProductName', str), ('OrderDate', date))
    orderz.insert(1, 'Geitost', date(2008, 11, 11))
    orderz.insert(2, 'Camembert Pierrot', date(2008, 11, 9))
    orderz.insert(3, 'Mozzarella di Giovanni', date(2008, 11, 11))
    orderz.insert(4, 'Mascarpone Fabioloi', date(2008, 10, 29))
    # Query the table for a specific date.
    orderz.where(ROW.OrderDate == date(2008, 11, 11)).print()
    # Update the orderz table so that times are present with the dates.
    orderz.alter_column('OrderDate', datetime)
    orderz.where(ROW.OrderId == 1) \
                        .update(OrderDate=datetime(2008, 11, 11, 13, 23, 44))
    orderz.where(ROW.OrderId == 2) \
                        .update(OrderDate=datetime(2008, 11, 9, 15, 45, 21))
    orderz.where(ROW.OrderId == 3) \
                        .update(OrderDate=datetime(2008, 11, 11, 11, 12, 1))
    orderz.where(ROW.OrderId == 4) \
                        .update(OrderDate=datetime(2008, 10, 29, 14, 56, 59))
    # Query the table with a datetime object this time.
    orderz.where(ROW.OrderDate == datetime(2008, 11, 11)).print() 

def test():
    "Runs several groups of tests of the database engine."
    # Test simple statements in SQL.
    persons = test_basic_sql()
    # Test various ways to select rows.
    test_row_selection(persons)
    # Test the four different types of joins in SQL.
    orders = test_all_joins(persons)
    # Test unstructured ways of joining tables together.
    test_table_addition(persons, orders)
    # Test creation and manipulation of databases.
    test_database_support()
    # Load and run some test on the sample Northwind database.
    northwind = test_northwind()
    # Test different date operations that can be performed.
    test_date_functionality()
    # Test various functions that operate on specified column.
    test_column_functions()
    if northwind:
        # Test ability to select columns with function processing.
        test_generic_column_functions(persons, northwind)
    # Test Database2 instances that support transactions.
    nw2 = test_transactional_database()
    # Allow for interaction at the end of the test.
    globals().update(locals()) 

def begin_transaction(self, table, wait=False):
        "Locks and copies table while optionally waiting for unlock."
        table = self.__data.where(name=table)
        assert table.first('type') is not _View, 'Views are not supported!'
        lock = table.first('lock')
        if wait:
            lock.acquire()
            with self.__lock:   # Protects Critical Section
                data = table.first('data')
                table.update(copy=copy.deepcopy(data))
        else:
            with self.__lock:
                assert lock.acquire(False), 'Table is locked in a transaction!'
                data = table.first('data')
                table.update(copy=copy.deepcopy(data))
        return data 

def update(x, **entries):
    """Update a dict, or an object with slots, according to `entries` dict.

    >>> update({'a': 1}, a=10, b=20)
    {'a': 10, 'b': 20}
    >>> update(Struct(a=1), a=10, b=20)
    Struct(a=10, b=20)
    """
    if isinstance(x, dict):
        x.update(entries)
    else:
        x.__dict__.update(entries)
    return x

#______________________________________________________________________________
# Functions on Sequences (mostly inspired by Common Lisp)
# NOTE: Sequence functions (count_if, find_if, every, some) take function
# argument first (like reduce, filter, and map). 

def __init__(self, **entries):
        self.__dict__.update(entries) 

def __init__(self, order=min, f=lambda x: x):
        update(self, A=[], order=order, f=f) 

def update(self, other):
                for e in other:
                    self.add(e)
                return self 

def __copy__(self):
        copy = DefaultDict(self.default)
        copy.update(self)
        return copy 

def __init__(self, **entries):
        self.__dict__.update(entries) 

def __copy__(self):
            copy = defaultdict(self.default)
            copy.update(self)
            return copy 

def __init__(self, order=min, f=lambda x: x):
        update(self, A=[], order=order, f=f) 

def __copy__(self):
        copy = DefaultDict(self.default)
        copy.update(self)
        return copy 

def __extend_data(self):
        "Adds columns to internal table as necessary."
        if ('type', type) not in self.__data.schema:
            self.__data.alter_add('type', type)
            for name, data in rows(self.__data('name', 'data')):
                self.__data.where(name=name).update(type=type(data))
        self.__data.alter_add('lock', _Lock)
        self.__data.alter_add('copy', object) 

def __commit(table):
        "Deletes the reserve copy of a table."
        table.update(copy=object()) 

def __rollback(table):
        "Restores table from copy and deletes the copy."
        table.update(data=table.first('copy'), copy=object())

    ######################################################################## 

def update(self, **assignments):
        "Changes all present rows with given assignments."
        assign = []
        for name, value in assignments.items():
            data_type, index = self.__columns[name]
            assert isinstance(value, data_type), \
            'Wrong datatype: {} ({!r}, {!r})'.format(name, value, data_type)
            assign.append((index, value))
        for row in self.__data_area.values():
            for index, value in assign:
                row[index] = value 

def update(self, other):
                for e in other:
                    self.add(e)
                return self 

def __copy__(self):
        copy = DefaultDict(self.default)
        copy.update(self)
        return copy 

def test_basic_sql():
    "Tests simple statements in SQL."
    # Test create table statement.
    persons = Table(('P_Id', int), ('LastName', str), ('FirstName', str),
                    ('Address', str), ('City', str))
    # Populate the table with rows.
    persons.insert(1, 'Hansen', 'Ola', 'Timoteivn 10', 'Sandnes')
    persons.insert(2, 'Svendson', 'Tove', 'Borgvn 23', 'Sandnes')
    persons.insert(3, 'Pettersen', 'Kari', 'Storgt 20', 'Stavanger')
    persons.print()
    # Test the select statement.
    persons.select('LastName', 'FirstName').print()
    persons.select().print()
    # Test the distinct statement.
    persons.select('City').distinct().print()
    # Test the where clause.
    persons.where(ROW.City == 'Sandnes').print()
    # Test the and operator.
    persons.where((ROW.FirstName == 'Tove') &
                  (ROW.LastName == 'Svendson')).print()
    # Test the or operator.
    persons.where((ROW.FirstName == 'Tove') | (ROW.FirstName == 'Ola')).print()
    # Test both and & or operators.
    persons.where((ROW.LastName == 'Svendson') &
                  ((ROW.FirstName == 'Tove') |
                   (ROW.FirstName == 'Ola'))).print()
    # Test order by statement.
    persons.insert(4, 'Nilsen', 'Tom', 'Vingvn 23', 'Stavanger')
    persons.order_by('LastName').table().print()
    persons.order_by('LastName', True).table().print()
    # Test insert statement.
    persons.insert(5, 'Nilsen', 'Johan', 'Bakken 2', 'Stavanger')
    persons.print()
    persons.insert(P_Id=6, LastName='Tjessem', FirstName='Jakob')
    persons.print()
    # Test update statement.
    persons.where((ROW.LastName == 'Tjessem') &
                  (ROW.FirstName == 'Jakob')).update(Address='Nissestien 67',
                                                     City='Sandnes')
    persons.print()
    copy = persons.order_by('P_Id').table()
    copy.update(Address='Nissestien 67', City='Sandnes')
    copy.print()
    # Test delete statement.
    copy = persons.order_by('P_Id').table()
    copy.delete((ROW.LastName == 'Tjessem') &
                (ROW.FirstName == 'Jakob')).print()
    copy.truncate().print()
    return persons 

def test_northwind():
    "Loads and runs some test on the sample Northwind database."
    import os, imp
    # Patch the module namespace to recognize this file.
    name = os.path.splitext(os.path.basename(sys.argv[0]))[0]
    module = imp.new_module(name)
    vars(module).update(globals())
    sys.modules[name] = module
    # Load a Northwind database for various testing purposes.
    try:
        northwind = Database.load('northwind.db')
    except IOError:
        return
    # Create and test a current product list view.
    northwind.create('Current Product List', lambda db: db.Products.where(
        ROW.Discontinued.NOT).select('ProductID', 'ProductName'))
    northwind['Current Product List'].print()
    # Find all products having an above-average price.
    def above_average_price(db):
        return db.Products.where(ROW.UnitPrice > db.Products.avg('UnitPrice')) \
               .select('ProductName', 'UnitPrice')
    northwind.create('Products Above Average Price', above_average_price)
    northwind['Products Above Average Price'].print()
    # Calculate total sale per category in 1997.
    def category_sales_for_1997(db):
        result = Table(('CategoryName', str),
                       ('CategorySales', decimal.Decimal))
        for table in db['Product Sales For 1997'] \
            .group_by('Categories.CategoryName'):
            name = next(rows(table.select('Categories.CategoryName')))[0]
            total = table.sum_('ProductSales')
            result.insert(name, total)
        return result
    northwind.create('Category Sales For 1997', category_sales_for_1997)
    northwind['Category Sales For 1997'].print()
    # Show just the Beverages Category from the previous view.
    northwind['Category Sales For 1997'].where(
        ROW.CategoryName == 'Beverages').print()
    # Add the Category column to the Current Product List view.
    northwind.create_or_replace('Current Product List', lambda db: \
        db['Products View'].where(ROW.Discontinued.NOT) \
        .select('ProductID', 'ProductName', 'Category'))
    northwind['Current Product List'].print()
    # Drop the Category Sales For 1997 view.
    northwind.drop('Category Sales For 1997')
    return northwind