Brewery2 Example: using kernel function added_keys and added_rows. The added_rows will be called with two flavours: one as (sql, sql) the other will be retried with (rows, sql).

brewery2-added_rows.py

from brewery2 import k, open_store, FieldList

DATA_TARGET = [
            [1, "Janko",    "Bratislava"],
            [2, "Marienka", "Bratislava"],
            [3, "Jaga",     "Zvolen"]
        ]

DATA_SRC = [
            [1, "Janko",    "Bratislava"],
            [2, "Marienka", "Bratislava"],
            [3, "Jaga",     "Bratislava"],
            [4, "Vlk",      "Zvolen"]
        ]

# Open database store
store = open_store("sql", "sqlite:///")

# Create some example tables ...
src = store.create("src_customers", FieldList(("id", "integer"),
                                            ("name", "string"),
                                            ("city", "string")))
src.append_from_iterable(DATA_SRC)

target = store.create("dim_customers", FieldList(("id", "integer"),
                                                ("name", "string"),
                                                ("city", "string")))
target.append_from_iterable(DATA_TARGET)

# Some fun stuff

def try_added_keys():
    """Show all added keys"""
    diff = k.added_keys(src,target,"id")

    print("difference:")
    for row in diff:
        print(row)

def try_added_rows_composable():
    """Show all added rows using one nested SQL statement - because we can compose within one store"""

    diff = k.added_rows(src,target,"id")

    print("difference:")
    for row in diff:
        print(row)

def try_added_rows_noncomposable():
    """Show all added rows using an iterator - we can not compose, because data are in two stores"""
    
    another_store = open_store("sql", "sqlite:///")
    target = another_store.create("dim_customers", FieldList(("id", "integer"),
                                                    ("name", "string"),
                                                    ("city", "string")))
    target.append_from_iterable(DATA_TARGET)

    diff = k.added_rows(src,target,"id")

    print("difference:")
    for row in diff:
        print(row)